Blackwell′s Five–Minute Veterinary Consult Clinical Companion: Small Animal Dentistry [3 ed.] 1119584337, 9781119584339
The newly revised Third Edition of Blackwell's Five-Minute Veterinary Consult Clinical Companion: Small Animal Dent
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Blackwell’s Five‐Minute Veterinary Consult Clinical Clinical Companion Companion
Small Animal Dentistry
Blackwell’s Blackwell’s Five‐Minute Five‐Minute Veterinary Veterinary Consult Consult Clinical Clinical Companion Companion
Small Animal Dentistry Third Edition Edited by Heidi B. Lobprise, DVM, DAVDC Main Street Veterinary Hospital and Dental Clinic Flower Mound, Texas, USA Cibolo Creek Veterinary Hospital Boerne, Texas, USA
iii
This edition first published 2021 © 2021 John Wiley & Sons, Inc. Edition History 1st edition © Blackwell Publishing; 2nd edition © 2012 by John Wiley and Sons, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions. The right of Heidi B. Lobprise to be identified as the author of the editorial material in this work has been asserted in accordance with law. Registered Office John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA Editorial Office 111 River Street, Hoboken, NJ 07030, USA For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com. Wiley also publishes its books in a variety of electronic formats and by print‐on‐demand. Some content that appears in standard print versions of this book may not be available in other formats. Limit of Liability/Disclaimer of Warranty The contents of this work are intended to further general scientific research, understanding, and discussion only and are not intended and should not be relied upon as recommending or promoting scientific method, diagnosis, or treatment by physicians for any particular patient. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of medicines, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each medicine, equipment, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/ or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Library of Congress Cataloging‐in‐Publication Data Names: Lobprise, Heidi B., editor. Title: Blackwell’s five-minute veterinary consult clinical companion : small animal dentistry / edited by Heidi B. Lobprise. Description: Third edition. | Hoboken, NJ : Wiley, 2021. | Series: Blackwell’s five-minute veterinary consult | Includes bibliographical references and index. Identifiers: LCCN 2021014070 (print) | LCCN 2021014071 (ebook) | ISBN 9781119584339 (paperback) | ISBN 9781119584384 (adobe pdf) | ISBN 9781119584391 (epub) Subjects: LCSH: Veterinary dentistry–Handbooks, manuals, etc. Classification: LCC SF867 .L62 2021 (print) | LCC SF867 (ebook) | DDC 636.08976–dc23 LC record available at https://lccn.loc.gov/2021014070 LC ebook record available at https://lccn.loc.gov/2021014071 Cover Design: Wiley Cover Images: © Heidi B. Lobprise Set in 10/12pts Berkeley by SPi Global, Pondicherry, India 10 9 8 7 6 5 4 3 2 1
To the late Robert B. Wiggs, for getting me started in dentistry. To the amazing dental team at Main Street Veterinary Dental Clinic – I will miss you!
Contents
Contributors������������������������������������������������������������������������������������������������ x Preface�������������������������������������������������������������������������������������������������������xii Acknowledgments ������������������������������������������������������������������������������������ xiii About the Companion Website������������������������������������������������������������������ xiv Section
I
Diagnostics
1
Chapter 1
Oral Examination and Charting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2
Periodontal Probing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Chapter 3
Intraoral Radiology and Advanced Imaging . . . . . . . . . . . . . . . . . . . . . . . . 21
Section
II
Techniques
47
Chapter 4
Complete Dental Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Chapter 5
Periodontal Pocket Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Chapter 6
Gingival Flaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Chapter 7
Extraction Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Chapter 8
Oral Pain Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Chapter 9
Equipment, Instruments and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 97
Section
III
Oral/Dental Diseases: Developmental Oral/Dental Problems
111
Chapter 10
Persistent (Retained) Deciduous Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Chapter 11
Craniomandibular Osteopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Chapter 12
Enamel Hypocalcification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Chapter 13
Eruption Disruption/Abnormalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Chapter 14
Abnormal Number of Teeth (Decreased) . . . . . . . . . . . . . . . . . . . . . . . . . 131
Chapter 15
Abnormal Number of Teeth (Increased) . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Chapter 16
Abnormal Tooth Formation/Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Chapter 17
Dentigerous Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Chapter 18
Palatal Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Chapter 19
Malocclusions: Skeletal and Dental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 vii
viii Contents
Section
IV
Acquired Oral/Dental Diseases: Periodontal Problems
165
Chapter 20
Periodontal Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Chapter 21
Gingival Enlargement/Hyperplasia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Chapter 22
Oronasal Fistula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Chapter 23
Stomatitis and Oral Ulceration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Section
V
Acquired Oral/Dental Diseases: Enamel and Dentin Problems
193
Chapter 24
Discolored Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Chapter 25
Dental Caries (Cavities) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Chapter 26
Attrition/Abrasion/Wear of Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Section
VI
Chapter 27
Acquired Oral/Dental Diseases: Endodontic Problems
211
Tooth Root Abscess (Apical Abscess) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Chapter 28 Pulpitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Section
VII
Chapter 29
Acquired Oral/Dental Diseases: Neoplasia
225
Odontogenic Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Chapter 30 Odontoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 Chapter 31
Papillomatosis (Oral) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Chapter 32
Melanocytic Tumors (Oral) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Chapter 33 Fibrosarcoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 Chapter 34
Squamous Cell Carcinoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Chapter 35
Other Malignant Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Chapter 36
Benign Masses and Lesions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Section
VIII
Acquired Oral/Dental Diseases: Trauma
273
Chapter 37
Traumatic Dentoalveolar Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Chapter 38
Maxillary and Mandibular Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
Chapter 39
Temporomandibular Joint Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Section
IX
Feline Oral/Dental Disease
299
Chapter 40
Tooth Resorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Chapter 41
Feline Chronic Gingivostomatitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Contents
ix
Chapter 42
Chronic Osteitis/Alveolitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Chapter 43
Oral Manifestations of Feline Infectious Diseases . . . . . . . . . . . . . . . . . . . 321
Section
X
Special Categories
329
Chapter 44
Salivary Gland Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
Chapter 45
Other Soft Tissue Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Appendices345 Appendix A
The Use of Antibiotics in Veterinary Dentistry�������������������������������������������� 347
Appendix B
Companion Animal Dental Scaling Without Anesthesia���������������������������� 348
Appendix C
American Veterinary Dental College Nomenclature���������������������������������� 350
Appendix D
Internet Resources������������������������������������������������������������������������������������ 367
Appendix E
Dental Home Care������������������������������������������������������������������������������������ 368 Index�������������������������������������������������������������������������������������������������������� 376
Contributors
Kristin Bannon, DVM, FAVD, DAVDC Veterinary Dentistry and Oral Surgery of New Mexico, LLC Algodones, NM, USA Jan Bellows, DVM, DAVDC, ABVP (canine and feline) All Pets Dental Weston, FL, USA Randi Brannan, DVM, FAVD, DAVDC Animal Dental Clinic Lake Oswego, OR, USA Fraser A. Hale, DVM, FAVD, DAVDC Hale Veterinary Clinic Guelph, Ontario, Canada Jessica Johnson, DVM Main Street Veterinary Dental Clinic Flower Mound, TX, USA Laura Kempf, BS Lead Dentistry Technician Main Street Veterinary Dental Clinic Flower Mound, TX, USA Matthew S. Lemmons, DVM, DAVDC MedVet Medical and Cancer Centers for Pets Indianapolis, IN, USA John R. Lewis, VMD, FAVD, DAVDC Veterinary Dentistry Specialists Chadds Ford, PA, USA Heidi Lobprise, DVM, DAVDC Main Street Veterinary Dental Clinic Flower Mound, TX, USA Jennifer R. Mathis, DVM, CVPP Animal Dentistry Referral Services Norwalk, IA, USA
x
Contributors
Michael Peak, DVM, DAVDC The Pet Dentist at Tampa Bay Clearwater, FL, USA Alexander M. Reiter, Dipl. Tzt., Dr. med. vet., DAVDC, Dipl. EVDC, FF‐AVDC‐OMFS Professor of Dentistry and Oral Surgery School of Veterinary Medicine University of Pennsylvania Philadelphia, PA, USA Mark M. Smith, DVM, DAVDC, DACVS Founding Fellow, AVDC Oral and Maxillofacial Surgery Founding Fellow, ACVS Oral and Maxillofacial Surgery Center for Veterinary Dentistry and Oral Surgery Gaithersburg, MD, USA Christopher J. Snyder, DVM, DAVDC School of Veterinary Medicine University of Wisconsin‐Madison Madison, WI, USA Jason Soukup, DVM, DAVDC Clinical Associate Professor, Veterinary Dentistry and Oral Surgery School of Veterinary Medicine University of Wisconsin‐Madison Madison, WI, USA Kevin S. Stepaniuk, DVM, FAVD, DAVDC Veterinary Dentistry Education and Consulting Services, LLC Ridgefield, WA, USA Kendall Taney, DVM, DAVDC Center for Veterinary Dentistry and Oral Surgery Gaithersburg, MD, USA Shannon Van Trease Director of Veterinary Dentistry Main Street Veterinary Dental Clinic Flower Mound, TX, USA
xi
Preface
This updated third edition of Five‐Minute Veterinary Consult Clinical Companion: Small Animal Dentistry has undergone a moderate reorganization to keep it practical and up‐to‐date for general practitioners looking for a helpful reference guide in daily practice. Some changes include an enhanced pain management chapter with additional images for local blocks, an equipment and instrument chapter with tips on sharpening and maintenance, and two chapters coalescing pertinent data on less common malignant and benign masses. The epulis chapter has been replaced by one on odontogenic tumors, to provide a better understanding of this group of diseases. The tooth fracture chapter has been upgraded to encompass tooth–dentoalveolar injuries, while the chapters on squamous cell carcinoma and salivary gland disorders have been condensed into one chapter for each broader topic. The feline chapters include the updated nomenclature of tooth resorption and feline chronic gingivostomatitis, with a separate chapter for more general stomatitis and oral ulceration that includes canine issues as well. Some less common or integral subjects will only be found in the second edition, as transillumination, tight lip syndrome, bird tongue (microglossia), and halitosis have been covered in other topics. The chapter on other soft tissue disorders has brought in information from masticatory muscle myositis, trigeminal neuritis, and eosinophilic granuloma complex while adding other areas not covered previously. I have also deleted the “Business of Dentistry” section to concentrate on specific clinical issues frequently encountered. The appendices have been expanded to include a position statement and resources to help respond to the issue of anesthesia‐free dental procedures. There is also a listing of internet resources including the 2019 AAHA Dental Care Guidelines for Dogs and Cats and the WSAVA Global Dental Guidelines. Links to videos of some procedures will be available on the website. Overall, I hope this new edition will continue to be a well‐used resource for technicians and veterinarians alike. I am very thankful for all the contributors, past and present. Thanks also to Drs. Frank Smith and Larry Tilley for continuing their support of the Five‐Minute Veterinary Consult Clinical Companion series and the staff of John Wiley & Sons for their limitless patience in helping me with “rounding up all the cats.” I have been so blessed throughout the years with the opportunities God has given me, including my wonderfully patient husband, Joe. Heidi B. Lobprise
xii
Acknowledgments
Portions of chapters of this book have been provided by material contributed in previous editions and from related topics in Blackwell’s Five‐Minute Veterinary Consult: Canine and Feline by the following authors: James Anthony Larry Baker Don Beebe Susan Berryhill Bonnie Bloom William Gengler Cecelia Gorrel Barron Hall Thomas Klein Annie Mills Sunny Ruth Margaret C. Barr Matthew R. Berry Jenna H. Burton Elizabeth R. Drake Timothy M. Fan
xiii
About the Companion Website
The companion website for this book is at www.wiley.com/go/lobprise/dentistry The website contains: Handouts ■■ Dental Charts ■■ Anesthesia Charts ■■ Video Clips ■■
Scan this QR code to visit the companion website.
xiv
Section
I
Diagnostics
1
Chapter
1
Oral Examination and Charting INDICATIONS ■■
■■
■■
■■ ■■
“Every mouth, every time”: a complete oral examination should be performed whenever possible to detect lesions as early as possible. Make it a part of puppy and kitten exams to start a lifetime of oral care: •• Deciduous occlusion. •• Broken or damaged teeth. •• Proper eruption sequence. •• Brushing/home care instruction. Continue with oral examinations at each visit, making oral care a cornerstone of a wellness program. An alert oral exam can give a quick overview of oral conditions in most patients. A complete oral examination can only be performed under general anesthesia and will include physical examination of the oral and dental structures, periodontal probing, transillumination, and intraoral radiography.
EQUIPMENT AND RESOURCES (see Chapter 9) Alert Examination ■■ ■■ ■■ ■■
Adequate but gentle restraint Good lighting Charts Gloves
Complete Examination ■■ ■■ ■■
■■ ■■ ■■ ■■ ■■
General anesthetic components, including monitoring Good lighting Soft mouth blocks (gauze, spiral perm rollers): do not use spring‐loaded mouth gags, which can damage teeth or strain the temporomandibular joint unnecessarily, and can cause blindness in cats when they compress the maxillary artery Magnification (usually needed): loupes Periodontal probe/explorer Mirror (Figure 1.1) Transilluminator Charts
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 3
4
SECTION I DIAGNOSTICS
■■ Figure 1.1 A dental mirror allows you to examine the distal aspects of molars during therapy.
■■ Figure 1.2 Before looking inside the mouth, examine the entire head for abnormalities, such as the generalized swelling of the face of this dog (oral mass).
PROCEDURE Alert Examination ■■
■■
Use great caution with anxious or aggressive animals or those in pain; examination may have to be accomplished under sedation (carefully) or when the patient is anesthetized. With the patient gently restrained on the table or floor, first observe the external structures of the head for any irregularities: symmetry, swelling (Figure 1.2), discoloration, discharge; note any malodor (halitosis).
■■
■■
■■
CHAPTER 1 ORAL EXAMINATION AND CHARTING
5
Gently hold the muzzle closed with your nondominant hand, and lift up the lips to observe the buccal/labial surfaces of the teeth. Note and record: •• Accumulations of plaque and/or calculus (Figure 1.3). •• Missing teeth (circle on chart). •• Supernumerary teeth. •• Worn (AT for attrition), chipped, broken (FX for fractured) or discolored teeth. •• Gingival inflammation, overgrowth or recession. ◦◦ Red or bleeding gingiva: draining tract (parulis), purulent discharge. ◦◦ Gingival enlargement. ◦◦ Possible presence of tooth resorption (TR) – feline and canine. •• Position of teeth (occlusion). ◦◦ Incisors should be in “scissor bite” (Figure 1.4). ◦◦ Lower canine should be spaced equally between upper third incisor and upper canine. ◦◦ Premolars should interdigitate in a “pinking shear” configuration. ◦◦ Individual teeth in proper position. •• Oral soft tissues. ◦◦ Any fistula or defects. ◦◦ Note if any unusual masses are present; press up in the intermandibular space to lift tongue to view sublingual area (Figure 1.5). If the patient is not in pain, and will allow it, briefly open the mouth: •• Assess palate. •• Look at tongue, and even raise the tongue pushing with your finger in the intermandibular space. •• Caudal mouth: assess inflammation in any possible stomatitis case. With discolored teeth, occasionally a patient will allow you to transilluminate the tooth during the initial exam.
■■ Figure 1.3 During the alert exam in anxious patients, caution may be needed to carefully lift the lips with gentle restraint (use a tongue depressor to preserve your fingers), so the extent of calculus and plaque can be estimated (significant accumulations in this patient).
6
SECTION I DIAGNOSTICS
■■ Figure 1.4 This patient shows a variation from a correct “scissors” bite, with the left maxillary first incisor positioned behind the mandibular incisors (rostral crossbite).
■■ Figure 1.5 With a cooperative patient, the tongue can be elevated by pushing up with a finger in the intermandibular space.
Complete Examination Under General Anesthesia ■■ ■■
■■
Reevaluate occlusion before intubation. Initial identification of significant lesions to help treatment planning and inform owner of unexpected problems (“red flag check”). Continue more extensive evaluation of above indices (Table 1.1): •• Plaque index. •• Calculus index (Figure 1.6). •• Gingival index.
CHAPTER 1 ORAL EXAMINATION AND CHARTING
7
TABLE 1.1 Periodontal indices. Plaque index (PI) PI 0
No observable plaque
PI 1
Plaque covers less than one‐third of buccal surface
PI 2
Plaque covers between one‐ and two‐thirds of buccal surface
PI 3
Plaque covers greater than two‐thirds of buccal tooth surface
Calculus index (CI) CI 0
No observable calculus
CI 1
Calculus covering less than one‐third of the buccal tooth surface
CI 2
Calculus covering between one‐ and two‐thirds of the buccal surface with minimal subgingival extension
CI 3
Calculus covering greater than two‐thirds of the buccal surface and extending subgingivally
Gingival index (GI) GI 0
Normal healthy gingiva with sharp, noninflamed edges
GI 1
Marginal gingivitis; minimal inflammation at the free margin; no bleeding on probing
GI 2
Moderate gingivitis; wider band of inflammation; bleeding on probing
GI 3
Advanced gingivitis; inflammation clinically reaching mucogingival junction; spontaneous bleeding sometimes present
■■ Figure 1.6 A more accurate assessment of the extent of plaque and calculus accumulation can be determined under anesthesia. This patient shows moderate calculus accumulation (CI 2) and plaque accumulation (PI 2, covering the calculus). ■■ ■■ ■■ ■■
Missing teeth: radiograph for embedded or unerupted teeth (see Chapter 14). Supernumerary teeth: evaluate for potential interference, crowding (see Chapter 15). Abnormal teeth: aberration in size, structure; evaluate for vitality (see Chapter 16). Worn, chipped or fractured teeth; discolored teeth (see Chapters 24, 26 and 37).
8
SECTION I DIAGNOSTICS
•• Evaluate surface and determine if canal exposed (use periodontal explorer) (Figure 1.7). •• Transilluminate to assess pulp vitality: ◦◦ Place the transillumination beam behind the tooth being observed, and examine the extent of light transmitted through the tooth. ◦◦ Vital teeth should transilluminate well, allowing light to pass through the tooth structure, even showing the pink of the pulp (Figure 1.8).
■■ Figure 1.7 Explorer used to detect pulpal exposure of this left mandibular canine (complicated crown fracture).
■■ Figure 1.8 Transillumination of this maxillary left second incisor shows good light transmission: the pulp is apparently vital.
■■
CHAPTER 1 ORAL EXAMINATION AND CHARTING
9
◦◦ Nonvital teeth will not transilluminate well, appearing dark or dull, especially in the chamber portion (central), though the light will sometimes shine through the peripheral dentin to some degree (Figure 1.9). Note that the great majority of discolored teeth are nonvital and should be treated (Figure 1.10). ◦◦ Further evaluate with radiographs. •• Radiograph to evaluate periapical bone, canal size. Mobile teeth: assess periodontal status and/or root fractures (Table 1.2).
■■ Figure 1.9 Transillumination of this maxillary right canine shows poor light transmission: the pulp is apparently nonvital and warrants further diagnostic evaluation (radiography).
■■ Figure 1.10 Assessing the open canal and apical bone loss on this radiograph confirms that the canine shown in Figure 1.9 is nonvital and requires therapy (root canal or extraction).
10
SECTION I DIAGNOSTICS
TABLE 1.2 Tooth mobility (M) index. M0
Physiologic mobility up to 0.2 mm
M1
The mobility is increased in any direction other than axial over a distance of more than 0.2 mm and up to 0.5 mm
M2
The mobility is increased in any direction other than axial over a distance of more than 0.5 mm and up to 1.0 mm
M3
The mobility is increased in any direction other than axial over a distance exceeding 1.0 mm or any axial movement
TABLE 1.3 Common dental abbreviations. AL
Attachment loss
OM
Oral mass
AT
Attrition (wear)
ONF
Oronasal fistula
CA
Caries
PE
Pulp exposure
CWD
Crowding
PP
Periodontal pocket
ED
Enamel defect
RD
Retained (persistent) deciduous
EP
Epulis
RE
Root exposure
FE
Furcation exposure
ROT
Rotated tooth
FX
Fracture
RPC
Root planing, closed
GH
Gingival hyperplasia
RPO
Root planing, open
GV/GVP
Gingivectomy/plasty
RTR
Retained root
LPS
Lymphocytic plasmacytic (caudal) stomatitis
TR
Tooth resorption
M
Mobile tooth
X
Extraction
(.) (circled)
Missing tooth
XS
Extraction, surgical
OP
Odontoplasty
XSS
Extraction, surgical, with sectioning
■■
■■ ■■
Oral soft tissues: •• Oral masses: early detection is critical (see Chapters 29–36). •• Ulceration, depigmentation (see Chapters 23 and 41). Periodontal probing (see Chapter 2). Intraoral radiographs (see Chapter 3).
Charting ■■
■■
■■
Accurately record all variations from normal on chart (Table 1.3). See also Figures 1.11 and 1.12 Dental formulas: •• Canine permanent: 2 × (I 3/3; C 1/1; P 4/4; M 3/2) = 42 •• Canine deciduous: 2 × (I 3/3; C 1/1; P 3/3) = 28 •• Feline permanent: 2 × (I 3/3; C 1/1; P 3/2; M 1/1) = 30 •• Feline deciduous: 2 × (I 3/3; C 1/1; P 3/2) = 26 Modified Triadan system can be used to identify teeth: •• Quadrant numbering ◦◦ “100”: upper right quadrant ◦◦ “200”: upper left quadrant
CHAPTER 1 ORAL EXAMINATION AND CHARTING
11
Main Street Veterinary Dental Clinic - Canine Dental Chart Client name: Patient name: Date: Breed: Assessment : Radiographs: ___Full ___Partial ___None
Client #: Patient #:
Chief Complaint:
Treatment: Clean/Polish/Dental Exam____ Periodontics Endodontics Exodontics Orthodontics Comments:
Post tx instructions: Antibiotics: Pain meds: Diet: ___Normal ___Soft Prevention: ____ Oral hygiene rinse ______ Daily Brushing ______ SANOS dental sealant ______Healthymouth ______ Dental Diet Recheck exam scheduled:__________ Next oral procedure scheduled: __________
AB abrasion
DTC dentigerous cyst
MAL malocclusion
PE pulp exposure
SE extrinsic staining
AT attrition
ED enamel defect
MN mandible
PP periodontal pocket
SI intrinsic staining
B/E biopsy excisional
E/H enam. hypoplasia
MX maxilla
PRO peridontal prohylaxi SN supernumerary
B/I biopsy incisional
FB foreign body
NE near exposure
R/C restoration w/ comp ST stomatitis
BG bone graft
FX fracture (tooth /jaw)
NV non-vital tooth
RC root canal therapy
SYM/S symphseal sep
CA caries
FE furcation exposure
OM oral mass
RD retained deciduous
T/I tooth impaction
CAO chron alv osteitis GH gingival hyperplasia ONF oronasal fistula
RE root exposure
TR tooth resorption
CFP Cleft palate
RPC root planing closed UE under erupted
GR gingival recession
PD1 gingivitis only
CRA crown amputation GP/GV gingivoplasty/ectoPD2 50% attach loss
RTR retained tooth root XSS extraction surgical
■■ Figure 1.11 Canine dental chart. Source: courtesy of Main Street Veterinary Dental Clinic – SVP.
◦◦ “300”: lower left quadrant ◦◦ “400”: lower right quadrant •• Tooth numbering ◦◦ Start at central incisor: “_01” ◦◦ Canines: “_04”
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SECTION I DIAGNOSTICS
Main Street Veterinary Dental Clinic - Feline Dental Chart Client name: Patient name: Date: Breed: Assessment : Radiographs: ___Full ___Partial ___None
Client #: Patient #:
Chief Complaint:
Treatment: Clean/Polish/Dental Exam ___ Periodontics Endodontics Exodontics Orthodontics Comments:
Post tx instructions: Antibiotics: Pain meds: Diet: ___Normal ___Soft Prevention:
AB abrasion
DTC dentigerous cyst
MAL malocclusion
PE pulp exposure
SE extrinsic staining
___Oral Rinse ___Daily Brushing ___SANOS ___t/d Dental Diet ___Healthy Mouth
AT attrition
ED enamel defect
MN mandible
PP periodontal pocket
SI intrinsic staining
B/E biopsy excisional
E/H enam. hypoplasia
MX maxilla
PRO peridontal prohylaxis
SN supernumerary
B/I biopsy incisional
FB foreign body
NE near exposure
R/C restoration w/ comp
ST stomatitis
BG bone graft
FX fracture (tooth /jaw)
NV non-vital tooth
RC root canal therapy
SYM/S symphseal sep
CA caries
FE furcation exposure
OM oral mass
RD retained deciduous
T/I tooth impaction
Recheck exam :__________
CAO chron alv osteitis
GH gingival hyperplasia
ONF oronasal fistula
RE root exposure
TR tooth resorption
CFP Cleft palate
GR gingival recession
PD1 gingivitis only
RPC root planing closed
UE under erupted
Next oral procedure : _______
CRA crown amputation
GP/GV gingivoplasty/ectomy PD2 50% attach loss
RTR retained tooth root
XSS extraction surgical
X extraction
■■ Figure 1.12 Feline dental chart. Source: courtesy of Main Street Veterinary Dental Clinic – SVP.
◦◦ Fourth premolar: “_08” ◦◦ Example: right upper fourth premolar, “108” ◦◦ Example: left lower first molar, “309” •• Variations ◦◦ Feline: no maxillary first premolar or mandibular first and second premolars, so “first” premolars are “106” and “206” in the maxilla, and “307” and “407” in the maxilla; only first molar present all four quadrants
CHAPTER 1 ORAL EXAMINATION AND CHARTING
13
◦◦ Canine: no maxillary third premolar ◦◦ Deciduous teeth: “add” 400 to quadrant number – 500 to 800, no deciduous molars, only premolars
COMMENTS ■■
A thorough examination can be performed on every patient in a reasonable amount of time and is essential to detect any abnormalities that may be present.
See also the following chapters: Chapter 2 ■■ Chapter 3 ■■ Chapter 9 ■■ Chapter 14 ■■ Chapter 15 ■■ Chapter 16 ■■ Chapter 24 ■■ Chapter 26 ■■ Chapter 23 ■■ Chapters 29–36 ■■ Chapter 37 ■■ Chapter 41 ■■ Appendix C ■■
Abbreviations See Table 1.3.
Internet Resources https://avdc.org/avdc‐nomenclature/ Authors: Laura Kempf, BS and Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
2 Periodontal Probing
INDICATIONS ■■
Every patient that is anesthetized for any dental procedure should have a complete dental examination performed, including periodontal probing of every tooth surface.
EQUIPMENT (see Chapter 9) Periodontal Probe ■■ ■■
■■
Round, flat. Marked in millimeters, various markings (Figure 2.1). •• Some marked with indentations at 1, 2, 3, 5, 7, 8, 9, and 10 mm. •• Some marked in alternating 3‐mm bands of black and silver. Pressure‐sensitive: plastic probe with additional indicator that is depressed when too much pressure is applied.
■■ Figure 2.1 Each periodontal probe has markings in millimeters to allow measurement of pocket depth and root exposure/gingival recession.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 14
chapter 2 Periodontal Probing
15
■■ Figure 2.2 Explorer tip (shepherd’s hook).
Periodontal Explorer (Other End of Many Probes) ■■
■■
“Shepherd’s hook”: sharp, slender tip used as tactile instrument to detect soft enamel (pre‐carious), open canals and enamel defects, especially feline resorptive lesions (Figure 2.2). Can be gently used subgingivally to detect calculus deposits.
PROCEDURE ■■
■■
■■
■■
■■
■■
Initial assessment with probe in the early stages of dental therapy to identify specific areas of concern (“red flag check”) for better treatment planning and to inform owner of unexpected problems: •• Palatal pockets of maxillary canines. •• Pockets between mandibular canines and incisors. •• Pockets at mesial or distal surface of mandibular molars. •• Any chipped or broken teeth to assess pulp exposure. Complete probing and charting must be done after plaque and calculus is removed because some areas will be occluded with the debris. After cleaning (in lateral positioning) each “half‐mouth” examine and probe the buccal/ facial surfaces of the “upside” and the lingual/palatal surfaces of the “downside.” Gently insert the probe into the gingival sulcus, advancing to the depth of the sulcus or pocket until touching the base (Figure 2.3). Note: with inflamed pockets, the probe can easily be pushed past the base attachment because the tissue is delicate – use great care! “6‐points” refers to gently placing the probe at the six line angles of the tooth (in human dentistry with interproximal contact points, the probe cannot be advanced circumferentially around the tooth). Alternatively, probe circumferentially around the tooth. Measure and record abnormalities encountered: •• The base of the sulcus or pocket is the level of attachment; any abnormality is an indication of attachment loss. •• Periodontal pocket (PP): pathologic depth greater than normal sulcus. ◦◦ Greater than 2–3 mm in the dog (more critical in smaller dogs). ◦◦ Greater than 0.5 mm in the cat (Figure 2.4).
16
SECTION I DIAGNOSTICS
■■ Figure 2.3 The tip of a periodontal probe is gently inserted into the gingival sulcus or pocket and advanced carefully to the base (without penetrating tissue further).
■■ Figure 2.4 Normal sulcus depth in a cat is usually less than 0.5 mm, so 3 mm the pocket on the distal/palatal aspect of the right maxillary canine (104) is significant for this cat.
◦◦ Mark “PP” and millimeter depth on chart: there may be several measurements recorded around an individual tooth. •• Gingival recession (GR) or root exposure (RE): area of exposed root now visible due to gingival and alveolar bone loss (Figure 2.5). ◦◦ Mark “GR” or “RE” and mm depth on chart. ◦◦ If additional pocket formation, mark that as well. •• Attachment loss (AL) (see Chapter 26). ◦◦ Any decrease or apical “movement” of the attachment level. ◦◦ Combination of RE and PP depths.
chapter 2 Periodontal Probing
17
■■ Figure 2.5 Total attachment loss (AL) on the right maxillary canine (104) of this cat is the summation of root exposure (3 mm) and pocket depth (3 mm), a significant level of loss.
■■
■■
◦◦ Total AL is the measurement from original site of attachment at the neck of the tooth (cementoenamel junction, CEJ) to the depth of the pocket. •• Furcation exposure (FE): space between roots of multirooted teeth are exposed due to gingiva and bone loss. ◦◦ F1: stage 1 exists when a periodontal probe extends less than halfway under the crown in any direction of a multirooted tooth with AL. ◦◦ F2: stage 2 exists when a periodontal probe extends greater than halfway under the crown of a multirooted tooth with AL but not through and through. ◦◦ F3: stage 3 exists when a periodontal probe extends under the crown of a multirooted tooth, through and through from one side of the furcation out the other. Areas of note: while every tooth surface should be probed and examined, there are specific areas that demand special attention or can often be accompanied by minimal outward indications (see “red flag check” above). •• Palatal surface of maxillary canines (Figure 2.6): an inapparent deep infra‐bony pocket may be present and, if advanced, the bone loss can form a communication into the nasal cavity, which would then necessitate extraction of the canine and special closure of the oronasal fistula (ONF) (see Chapter 22). Early intervention before fistula formation is essential. •• Rostral/mesial surface of mandibular canines (Figure 2.7): a significant pocket beside the lower third incisor can significantly compromise the lower canine, and advanced procedures may be used to save the incisor or more thoroughly treat the lower canine and soft tissues once the incisor is extracted. •• Lower first molar, mesial and distal surfaces (Figure 2.8): deep pockets at either aspect of this tooth can lead to further compromise of the mandible itself, especially in small‐breed dogs. Gingival margins may indicate no external problems, so careful probing is essential. Periodontal explorer •• Sharp tip is very tactile: ◦◦ Evaluate areas of tooth wear or fracture to determine if canal is exposed (Figure 2.9) (see Chapter 26). ◦ ◦ Evaluate areas of potential resorptive lesions in cats (Figure 2.10) (see Chapter 40).
■■ Figure 2.6 Probing the palatal surface of this left maxillary canine (204) reveals extensive pocket depth that may be indicative of oronasal fistulation.
■■ Figure 2.7 Increased pocket depth at the mesial aspect of the mandibular canine (304) can often be treated with periodontal therapy.
■■ Figure 2.8 A pocket at the distal aspect of the right mandibular first molar (409) indicates significant attachment loss.
chapter 2 Periodontal Probing
19
■■ Figure 2.9 The explorer should be used on worn tooth surfaces to determine if a canal is exposed or, as in this case, if the explorer glides along the very smooth surface of the worn tooth manifesting reparative dentin (brown appearance); gradual wear may keep the pulp protected.
■■ Figure 2.10 The explorer tip can be used to detect resorptive lesions, especially those hidden under inflamed gingiva.
COMMENTS ■■
Every clinic should provide sufficient instrumentation and sufficient time to thoroughly examine and probe the periodontal tissues around every tooth. It is a simple procedure that is often overlooked or underperformed.
See also the following chapters: Chapter 1 ■■ Chapter 9 ■■ Chapter 20 ■■ Chapter 26 ■■ Chapter 40 ■■ Appendix C (Furcation Involvement/Exposure) ■■
20
SECTION I DIAGNOSTICS
Abbreviations ■■ ■■ ■■
AL = attachment loss CEJ = cementoenamel junction FE = furcation exposure
■■ ■■ ■■
ONF = oronasal fistula PP = periodontal pocket RE = root exposure.
Internet Resources https://avdc.org/avdc‐nomenclature/ Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
3
Intraoral Radiology and Advanced Imaging INDICATIONS Intraoral radiology is an integral part of veterinary dentistry, from diagnostics to therapy to evaluation of response to therapy. ■■ Necessary: full mouth radiographs on every patient, each dental visit. ■■ Survey: assess normal anatomy, use as baseline. ■■ Tooth abnormalities: size, structure, variation in number (absence or multiple). ■■ Periodontal disease: assess extent and nature of periodontal bone loss. It is critical to assess prior to treatment to recognize potential for iatrogenic fracture before tooth exfoliation. ■■ Endodontic disease: assess pulpal vitality (canal width and any periapical bone loss). ■■ Acquired diseases (caries, resorptive lesions). Feline root resorption and neck lesions are often undetected until late in the disease when radiographs have not been taken. ■■ Trauma: evaluate extent of osseous and dental damage. ■■ Neoplasia: evaluate extent of osseous involvement. ■■ Post procedure: document complete extraction for medical record. •• One study [1] has shown that 86% of extracted dog and cat carnassials with expected complete extraction left behind retained roots, sources of infection and pain. Use post‐ extraction radiographs to confirm the entire tooth has been removed. •• Showing radiographs and images to clients improves patient care and acceptance of treatment plans [2].
EQUIPMENT ■■
Radiographic unit (Figure 3.1) •• A dental radiographic unit at the dental station provides convenience to take intraoral radiographs of every patient: this can be wall‐mounted, on a movable stand, or hand‐ held units. •• Cone beam computed tomography (CBCT) ◦◦ Three‐dimensional view (voxels) of the hard tissues with less patient and operator radiation exposure [3]. ◦◦ Soft tissues imaged with high‐definition volumetric imaging (HDVI).* ◦◦ 90–1000 μm resolution depending on selected system capability.
Vimago™ Pico, Epica Animal Health, San Clemente, CA, USA.
*
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 21
22
SECTION I DIAGNOSTICS
■■ Figure 3.1 Radiographic generators: examples of wall‐mounted (left) and hand‐held (center) dental radiographic generators. Always stand at least 6 feet (2 meters) away from the beam and/or 270° to the side. (Right) Example of a cone beam computed tomography (CBCT) unit. Some units allow only extremities to be imaged. Others can image all body areas and more than hard tissue. ■■
■■
■■
Intraoral films (no. 2 and no. 4 common sizes) •• Require development: chairside or automatic developer. •• Time lapse before images can be viewed on view box. •• Retakes due to inexperience or exposure adds to anesthetic time. Digital intraoral radiography (Figure 3.2) •• Direct digital radiography with solid‐state sensor: ◦◦ Sensor typically size no. 2, similar to no. 2 periapical intraoral film. ◦◦ Allows immediate review of image for adjustments. ◦◦ Sopix sensor has widest latitude of exposure, minimizing retakes [4]. ◦◦ Sensor may be expensive to replace. •• Indirect digital radiography: ◦◦ Phosphor plates allow for additional sizes such as no. 4 for larger view. ◦◦ Takes additional time to scan the phosphor plate in order to view the image and retake to adjust for positioning or exposure. Cone beam computed tomography (three‐dimensional imaging) (Figure 3.3) •• Complete a full mouth (skull) scan in as little as 24 seconds, minimizing anesthesia [3]. •• Visualize three‐dimensional structures without obstruction such as maxillary architecture. •• Confirm periapical changes, tooth resorption, and temporomandibular joint (TMJ) architecture earlier, with 50% more sensitivity [5,6]. •• Image pulmonary nodules as small as 1 mm, which is up to nine times smaller than nodule detection using three‐dimensional thoracic radiography [7]. •• Find twice as many traumatic injuries as missed with conventional radiology [8].
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
23
■■ Figure 3.2 (Left) No. 4 (occlusal) and no. 2 (periapical) phosphor plates for use in indirect digital radiology. The sizes are similar to commonly used nondigital intraoral films. (Right) Sopix digital sensor, similar to no. 2 size of intraoral dental film.
(a)
(b)
(c)
(e)
(d)
■■ Figure 3.3 Example images acquired in a CBCT scan: (a) sagittal, (b) axial, and (c) coronal “slices”; (d, e) three‐ dimensional reconstructions for viewing. Maxillary obscured periapical and periodontal disease in the 200 quadrant is revealed.
24
SECTION I DIAGNOSTICS
PROCEDURE Taking Radiographs ■■
■■
■■
For intraoral films, the patients must be under general anesthesia: all considerations should be met (preoperative diagnostics, patient monitoring and support). Some tools that can help in taking images include the following (Figure 3.4): •• Flexible spiral perm roller (from beauty supply stores): can be used to keep sensor in proper position and as a soft mouth gag or wedge. Spring‐loaded mouth gags are inappropriate for veterinary dentistry, are known to cause blindness in cats, [9] and are also risky for dogs. •• Two tongue depressors joined with a push pin: simple device to help position radiographic beam for intraoral films. •• Roll of tape: to visually estimate the direction from which the radiographic beam should be aimed. Positioning of the film within the oral cavity and positioning of the radiographic beam can be a challenge. •• Place flat aspect of sensor or white side of film towards X‐ray source. •• Place film so image of roots will be captured, not crown (Figure 3.5). With a larger dog, this may involve placing the sensor or film further onto the palate or deeper in the intermandibular space. If the periodontal bone margin needs to be evaluated, place sensor centered at the neck of the tooth.
Parallel Technique (Sandwich Technique) Intraoral film or sensor placed lingual and parallel to (just inside and flat against) the mandibular premolars and molars: place the diagonal of the film across the position of the roots, with a corner sticking into the intermandibular space (Figure 3.6). ■■ Radiographic beam aimed perpendicular to both film and teeth. ■■
Shadow Technique (Modified “Bisecting Angle” Technique) In all other teeth, the sensor/film cannot be placed parallel to the teeth; there will be some space between the tooth/root and film. ■■ Position film as close to the tooth/root to be imaged as possible: you need to evaluate the roots, not the crown. ■■
■■ Figure 3.4 Three tools to help with taking radiographs: spiral perm roller for keeping sensor/film in place; two tongue depressors attached with a push‐pin; and roll of tape.
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
25
■■ Figure 3.5 Intraoral films should be placed such that the image of the roots, not the crown, will be seen on the film; this film was placed against the palate to image the roots of the upper fourth premolar.
■■ Figure 3.6 Parallel placement of an intraoral film to image the mandibular premolars and molars, as demonstrated on this cat skull. Note the corner is pushed into the intermandibular space.
■■
■■
■■
If the beam was aimed perpendicular to the film (Figure 3.7): •• This would result in a “shadow” or image of the tooth on the film that would be too short (think of a tree at noon). •• Therefore, perpendicular to film: too short (of an image). If the beam was aimed perpendicular to tooth root(s) (Figure 3.8): •• This would result in a “shadow” or image of the tooth on the film that would be too long (think of a tree at daybreak). •• Therefore, perpendicular to tooth: too long (of an image). Split the difference: come halfway between the two positions (Figure 3.9): •• The resulting “shadow” or image will be a compromise between the foreshortened and elongated images, with the image the approximate length of the tooth itself. •• In some of the images, a positioning device was made of two tongue depressors. The blue portion is aimed perpendicular to the film, and the red portion is aimed
26
SECTION I DIAGNOSTICS
■■ Figure 3.7 When imaging these maxillary incisors and canines, if the beam were aimed perpendicular to the film, the images would be foreshortened.
■■ Figure 3.8 If the beam were aimed perpendicular to the teeth (roots), the images would be elongated.
■■
erpendicular to the tooth root. The X‐ray beam/source is then positioned midway p between the two. •• The positioning tool made of regular tongue depressors (see Figure 3.4) has the terms “Perpendicular to film – too short” and “Perpendicular to tooth – too long” printed on them to help determine the proper angles. Other teeth: •• Mandibular incisors/canines ◦◦ Perpendicular to film (Figure 3.10): too short. ◦◦ Perpendicular to teeth (Figure 3.11): too long. ◦◦ Split the difference (Figure 3.12). •• Maxillary upper fourth premolar in dog ◦◦ Perpendicular to film (Figure 3.13): too short. ◦◦ Perpendicular to teeth (Figure 3.14): too long. ◦◦ Split the difference (Figure 3.15).
■■ Figure 3.9 By “splitting the difference” between the two positions, the images will be closer to the actual size of the structures, minimizing distortion. The radiographic aid is placed with the green stick perpendicular to the film and the red stick perpendicular to the tooth (root). The beam is aimed midway between the two sticks.
■■ Figure 3.10 Mandibular incisors/canines: beam perpendicular to film.
■■ Figure 3.11 Mandibular incisors/canines: beam perpendicular to teeth (roots).
■■ Figure 3.12 Mandibular incisors/canines: split the difference.
■■ Figure 3.13 Maxillary premolars/molars: perpendicular to film.
■■ Figure 3.14 Maxillary premolars/molars: perpendicular to teeth (roots).
■■
■■
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
29
•• Maxillary incisors/canines in cat ◦◦ Perpendicular to film (blue positioning guide). ◦◦ Perpendicular to teeth (red positioning guide). ◦◦ Split the difference (Figure 3.16). When positioning the beam, make sure it is aimed directly over the tooth (maxillary fourth premolar) or at midline (mandibular or maxillary incisors and canines for symmetry) (Figure 3.17). Adjust beam (laterally or obliquely for canines or mesially or distally for premolars) to “move” the superimposed apices away from each other (Figure 3.18). Hint. Maxillary incisors and canines: on most dogs and cats (not brachycephalic breeds), aim the beam perpendicular to the ventral aspect of the nasal fold (or haired portion of muzzle just under the nares); in most cases, the positioning will closely approximate the correct beam alignment (Figure 3.19). Position the beam initially based on the nares, and confirm the angle.
■■ Figure 3.15 Maxillary premolars/molars: split the difference.
■■ Figure 3.16 Maxillary incisors/canines in cat: positioning aids illustrating perpendicular to the film (blue) and perpendicular to the teeth roots (red); split the difference with the beam.
30
SECTION I DIAGNOSTICS
■■ Figure 3.17 Maxillary canines in dog: beam aimed initially at midline; roots of canines will be superimposed over premolar roots.
■■ Figure 3.18 Maxillary canines in dog: adjust beam away from midline to separate image of canine apex from premolars.
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
31
■■ Figure 3.19 In most dogs (not brachycephalic) and even some cats, by aiming the beam perpendicular to the ventral aspect of the nasal fold, the positioning will be adequate (approximates the split the difference position).
Challenging Radiographs Dog: maxillary canine apex (Figure 3.20). •• Place sensor/film centered at the second premolar and palpate apex of canine tooth. •• Aim beam towards palpated apex, slight oblique off midline (see Figure 3.18). ■■ Differentiation of mesial (towards the front of the tooth) and palatal roots of the upper fourth premolar (Figure 3.21). •• Shift the generator tube distally (towards the back of the tooth) to image the entire tooth without superimposition of the distal root over the first molar. •• Classically called SLOB (same lingual/opposite buccal) [4]. This means that the root that is more lingual (or palatal) will be imaged in the same direction. The root that moves in the opposite direction as the tube is the buccal root. •• If the distal root of the upper fourth premolar is imaged well (distal tube shift), the palatal root will move distally (the same direction as the tube) in comparison to the buccal root. The palatal root is in the middle of the distal and mesial roots (Figure 3.21). ■■ Dog: maxillary molars. •• Place sensor/film lengthwise palatally, lined up with the two molars. •• Aim beam from above and slightly behind, almost directly aimed at film (Figure 3.22). ■■ Dog: mandibular first premolars. It is challenging to place sensor far enough rostral in the intermandibular space for true parallel image. •• Intraoral: with sensor/film in place, aim beam from a position below (ventral) and rostral; this will “push” the image onto the film (Figure 3.23). ■■ Dog: mandibular second and third molars. •• Pull the patient’s tongue out to allow the sensor/film to slide by the oral soft tissues. •• Position sensor/film further caudally, but also dorsally. Usually the caudal aspect of the sensor/film is angled and above the rostral half of the sensor/film (keep in place with perm roller). ■■
■■ Figure 3.20 Maxillary canine apex in dog: aim beam towards palpated apex, slight oblique off midline. (a)
(b)
■■ Figure 3.21 (a) Standard beam positioning for the upper fourth premolar and its radiograph. (b) Beam position with distal tube shift and SLOB technique radiograph showing the palatal root in the middle.
■■ Figure 3.22 Maxillary molars in dog: place sensor/film lengthwise palatally, lined up with the two molars. Aim beam from above and slightly behind, almost directly at film.
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
33
■■ Figure 3.23 Mandibular first premolars in dog: with sensor/film in place intraorally, aim beam from a position below (ventral) and rostral. This will “cast the shadow” or “push” the image onto the film.
■■ Figure 3.24 Mandibular second and third molars in dog: position sensor/film further caudally, but also dorsally; don’t let it slide ventrally (keep in place with perm roller). Aim beam from a position caudal and dorsal to the film, using the tape roll to assist; this will “cast the shadow” or “push” the teeth onto the image.
■■
•• Aim beam from a position caudal and dorsal to the film. This will “push” the teeth onto the image, using the tape roll to assist (cast the shadow onto the film) (Figure 3.24). Maxillary premolars of cats and brachycephalic dogs. •• Keep mouth open with perm roller or 30‐mm clear mouth gag [9], place sensor/film under the maxillary premolars on the downside, slightly dorsal to the teeth (Figure 3.25). •• Aim beam from above and caudally, at a slight oblique, so the image of the “downside” maxillary premolars will be projected on the film underneath (follow the beam), and the “upside” maxillary teeth will not be superimposed (Figure 3.26). Mark the image as extraoral for later identification purposes. •• Note: since the beam is further from the film than in an intraoral method, additional exposure time may be necessary.
34
SECTION I DIAGNOSTICS
■■ Figure 3.25 Maxillary premolars of cats and brachycephalic dogs: keep mouth open with perm roller or 30‐mm clear mouth gag. Place sensor/film under the maxillary premolars on the “downside,” more dorsal to the teeth.
■■ Figure 3.26 Aim beam from above and caudally, at a slight oblique, so the image of the “downside” maxillary premolars will be projected on the film underneath (follow the beam), and the “upside” maxillary teeth will not be superimposed. Note or mark the film as extraoral for later identification purposes.
Preparing Images and Films An additional advantage of direct digital radiography is being able to immediately adjust the positioning of an image, or to adjust the amount of exposure. ■■ For images through the maxilla, of apical regions, or extraoral views, higher exposure times might be necessary to get sufficient clarity. ■■ For images through thinner bone, or to accurately assess the extent of periodontal bone loss, shorter exposure times might be necessary (Figure 3.27). ■■ The Sopix digital dental sensor has the widest latitude of exposure, minimizing the need for exposure adjustments [4].
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
(a)
35
(b)
■■ Figure 3.27 (a) Radiograph of right maxillary fourth premolar and first molar shows apparent significant periodontal bone loss, but crown density is also light, an indication of possible overexposure. (b) Repeat radiograph of maxillary premolar with decreased exposure shows moderate bone loss, a more accurate assessment. The Sopix sensor often accommodates to account for exposure issues.
RADIOGRAPHIC INTERPRETATION STEPS (Figure 3.28) Orientation of Films ■■
■■
■■
■■
Standard intraoral film positioning and viewing (nondigital films will have the embossed “dot” coming out towards you). Decide if the image is maxillary or mandibular. •• Maxillary: is there a white line formed by the dorsal plate of the alveolar process of the maxilla (see Figure 3.30)? (Remember, typically the only three rooted teeth are in the maxilla.) •• Mandibular: is the mandibular canal seen? Position the image with the crowns “in the mouth” like a Cheshire cat grin (mandibular roots pointing down, maxillary roots pointing up) (Figure 3.29). Identify side: •• For canines and incisors: “shake hands” – image’s right is on your left and image’s left is on your right (see Figure 3.28). •• For premolars: determine “which way is the nose”; is the rostral aspect of the image toward your right or toward your left (Figure 3.30)? •• Exception: for any extraoral film, right and left will be opposite as compared to an intraoral film (Figure 3.31).
Evaluation of Films Note Any Missing or Deciduous Teeth Utilizing the Triadan numbering system, the mouth is divided into quadrants. •• Remembering the mantras, “Do it right the first time” and “Always do your best/Be on top,” the top right quadrant is the 100s. •• As you look at the patient, the quadrants proceed clockwise (see Figure 3.29): ◦◦ Maxillary left quadrant is the 200s. ◦◦ Mandibular left quadrant is the 300s. ◦◦ Mandibular right quadrant is the 400s. ■■ Number from midline in each quadrant proceeding to the last molar: •• Incisors are _01 through _03. ■■
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SECTION I DIAGNOSTICS
SIMPLE STEPS FOR EACH FILM 1. Orient 2. Number teeth 3. PDL 4. Apex 5. Pulp width 6. Alveolar bone/Furcation 7. Crowns ■■ Figure 3.28 A summary of the simple steps to complete when interpreting radiographic film. The image shows dog mandibular incisors and canines, with missing lower right first incisor (401) and both first premolars (305, 405).
■■ Figure 3.29 Orient films with the crowns “in the mouth” like a Cheshire cat grin, with mandibular roots pointing down, maxillary roots pointing up. Triadan quadrant numbering begins in the top right and proceeds clockwise.
•• Canines are always _04. •• Premolars are _05 through _08: ◦◦ The large upper carnassial tooth is the fourth premolar = 1/208. ◦◦ Cats do not have any _05s nor lower _06s. •• Molars are _09 up to _11 when present: ◦◦ The large lower carnassial tooth is the first molar = 3/409. ◦◦ Normally the last maxillary tooth in the dog is 1/210.
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■■ Figure 3.30 Reading a radiograph. With premolars and molars, determine “where is the nose”; if the rostral aspect of the image is to the left, then the teeth are from a left quadrant. Images show left maxilla in a dog: note the white line formed by the dorsal plate of the alveolar process, present only in the maxilla.
■■ Figure 3.31 An extraoral film is read in the opposite way: right and left will be reversed compared to an intraoral film. Image shows left maxillary premolars in a cat (even though the nose is to the right).
■■
◦◦ Normally the last mandibular tooth in the dog is 3/411. ◦◦ There is only M1 in each quadrant of the cat = _09. Deciduous teeth without permanent successors can be assessed as any other tooth periodontally and endodontically. They typically have finer/thinner crowns and roots and are designated by adding 400 to the normal permanent Triadan number.
Identify Tooth Structures Identify normal anatomical tooth structures, noting abnormal as you diagnose each tooth “patient” present. Consider comparing to the same teeth of the opposite side. ■■ Periodontal ligament (PDL) (the black line surrounding the root): •• A widened PDL can indicate tooth subluxation or periodontal disease, though changes may be subtle. •• More commonly, a missing or moth‐eaten pattern to the PDL can be noted with replacement tooth resorption (see later bullet point on tooth resorption and Chapter 40).
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SECTION I DIAGNOSTICS
◦◦ Typical extraction with periodontal ligament elevation may not be possible (Figure 3.32). •• Evaluate any abnormalities, such as extra roots, abnormally shaped roots (dilacerated), fused roots, or compromised bone (see Chapter 16). Apex (tip of the root) •• Extension of disease into the periapical region can cause a “mushroom cloud”‐like lesion as one sign of endodontic (internal tooth) disease (Figure 3.33) (see Chapter 27).
■■ Figure 3.32 If there is extensively ankylosis or resorption of the roots, as in this dog’s left maxillary premolars, there is no periodontal ligament left to elevate, so the extraction procedure will be altered.
■■ Figure 3.33 Periapical bone loss (halo of osteolucency around an apex) is generally a reliable indication of a periapical abscess due to the loss of the pulp’s vitality. Image shows right mandibular molars in a dog.
CHAPTER 3 INTRAORAL RADIOLOGY AND ADVANCED IMAGING
■■
39
•• Do not mistake this for the chevron sign, a possible artifact of healthy teeth. ◦◦ May be a normal PDL thickening of mandibular M1. ◦◦ Contrasting trabecular bone with dense alveolar bone wall is commonly mistaken for a problem in the upper incisors and canines (Figure 3.34). Look for a continuous lamina dura, the white line continuing as if an extension of the PDL. Pulp width (see Figure 3.34) •• Teeth age inversely to the way trees do – as the tooth ages, dentin is laid down. ◦◦ Younger patients have wider pulp chambers. ◦◦ Older patients have narrower pulp chambers. •• Cessation of dentin deposition indicates the tooth has died and is endodontically compromised, requiring root canal therapy or extraction. •• Compare to the opposite side; look for discoloration (Figure 3.35b). ◦◦ Transilluminate to look for vitality, like candling an egg. Vital tooth transillumination is shown in Figure 3.35a. The right maxillary canine does not transilluminate and is nonvital (Figure 3.35c) (see Chapter 1).
■■ Figure 3.34 The pulp width of 104 (right) is wide compared to the same tooth in a dog of a similar age and breed (left). The other sign indicating a nonvital tooth is periapical lucency. A normal chevron sign, as indicated by the presence of the lamina dura, is seen on the healthy tooth.
(a)
(b)
(c)
DISCOLORED OR FRACTURED TEETH The only appropriate choices are root canal therapy or extraction. ■■ Figure 3.35 Note the pink/purple hue of this dog’s right maxillary canine as compared to the opposite side (b). Transillumination shows a vital tooth (a), whereas the right maxillary canine does not transilluminate and is nonvital (c).
40
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SECTION I DIAGNOSTICS
◦◦ The majority (92%) of discolored teeth have pulp necrosis while only 57% show radiographic signs. This means that 43% appear discolored/dull but still have pulp necrosis [10]. Pulp necrosis leads to periodontitis, osteomyelitis and/or systemic infection. These teeth are or will be painful. Alveolar bone levels surrounding the tooth and the furcation (periodontal disease). •• Assess the extent: ◦◦ Estimate percent of attachment loss to determine stage of periodontal disease (see Chapter 20). ◦◦ Extensive bone loss may alert you to compromised jaw strength if extractions planned. •• Assess the pattern of bone loss: ◦◦ Horizontal bone loss: pattern of bone loss across several roots or teeth showing a flattened or scalloped loss; if accompanied by gingival recession, this will result in root and/or furcation exposure (Figure 3.36). ◦◦ Vertical bone loss: pattern of bone loss extending down the axis of a root or roots and often associated with a deep infra‐bony pocket; if this extends to the periapical region, pulp can be compromised. If sufficient bony walls remain, guided tissue regeneration can be performed to return the bone to the height of the lowest bone wall (Figure 3.37). Crowns •• While not the focus of most intraoral radiographs, noting crown fractures and pulp chamber exposure is important. ◦◦ Endodontic disease is present if the pulp is exposed or the tooth is discolored. The only appropriate treatments are root canal therapy or extraction. As it can take six months [4,7] for enough mineral density change to be evident radiographically, a normal radiograph of an endodontically compromised tooth needs treatment, not watching and waiting. ◦◦ Other signs of endodontic disease, as illustrated in Figure 3.34, are periapical bone loss and a larger pulp chamber.
■■ Figure 3.36 Horizontal bone loss occurs with a linear pattern of bone height loss over several roots or several teeth. Image shows left mandible of a cat.
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■■ Figure 3.37 Vertical bone loss down a tooth root often results in deep infra‐bony pockets and can even extend to involve the root’s apex, which would compromise the tooth’s vitality, as shown in the distal root of the right mandibular first molar and mesial root of the second molar of this dog.
Additional Considerations ■■
■■
■■
Pre‐extraction (see Chapter 7) •• Ensure the mandibles and symphysis are intact and have sufficient bone supporting prior to extraction. •• Check for root dilaceration and resorption. Tooth resorption (TR): primarily cats, but also dogs (see Chapter 40). •• The decision on the methods of extraction in the case of TR is dependent on the visibility of the periodontal ligament. ◦◦ A focal lucency with visible PDL represents inflammatory (type 1) TR requiring traditional elevation to extract the tooth and its root (Figure 3.38). ◦◦ A ghosting appearance of the tooth root in which the PDL is not discernible is replacement resorption (type 2) (Figure 3.39). A modified extraction technique (MET) in which the crown is amputated to the level of alveolar bone and the area smoothed with a diamond bur is indicated. This results with intentional root retention (IRR). Follow‐up with annual radiographs is necessary to ensure the replacement resorption completes so that the retained portion is indistinguishable from alveolar bone. ◦◦ Removal of retained tooth root pieces using a high‐speed bur through root pulverization is contraindicated. Root pulverization is known to result in bone necrosis, air embolism, and sublingual/subcutaneous emphysema [4]. •• Root resorption (common in dogs) (Figure 3.40) ◦◦ When resorption occurs on the external surface and involves only the tooth root but not the neck or crown of the tooth, as is commonly seen in large‐breed dogs, no treatment is needed. Annual anesthetic preventive dental procedures with intraoral radiographs are needed for monitoring. If the resorption extends to the neck or crown of the tooth, and has access to the oral cavity or gingival sulcus, it is painful requiring extraction. Trauma (see Chapters 37 and 38) •• Intraoral films can target specific areas of traumatic damage. •• Sometimes, full skull radiographs give a broader picture of the extent of damage.
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■■ Figure 3.38 Some teeth that appear to have classic resorptive lesions display no odontoclastic activity (no replacement resorption) on radiographs. These teeth are more periodontally involved, with root exposure due to attachment loss (gingiva and bone loss) and subsequent erosion of the exposed portion of the root, but the submerged root remains intact, along with a distinct periodontal ligament space.
■■ Figure 3.39 Odontoclastic lesions (replacement resorption) of feline teeth need to be assessed radiographically. Often seen is the presence of root resorption with indistinguishable root, periodontal ligament space, and alveolar bone.
■■
•• Patients with trauma have 1.6–2 times more injuries as noted by CT which are missed with conventional radiology [8]. That is an average of three injuries per patient missed when three‐dimensional imaging is not utilized. Neoplasia •• Any suspicious lesion should be radiographed and biopsied (Figure 3.41). •• Be cautious with gingival enlargement: many benign‐looking changes are actually invasive painful growths, while not all show radiographic changes (Figure 3.42). All types of oral biopsies should be sent to an oral pathologist† for more definitive identification.
Specialty Oral Pathology for Animals, Geneseo, IL, USA.
†
■■ Figure 3.40 When resorption is on the external surface and involving only the tooth root but not the neck or crown of the tooth, as seen here in a dog, no treatment is needed. If the resorption extends to the neck or crown of the tooth, and has access to the oral cavity, it is painful requiring extraction.
■■ Figure 3.41 Radiographs may give an indication as to the severity of oral masses, particularly their osseous involvement, as in this aggressive squamous cell carcinoma in a feline mandible.
(a)
(b)
■■ Figure 3.42 (a) Presumed gingival enlargement and periodontal disease. (b) Four months later, the mass effect has become apparent. Radiographic signs of neoplasia were not present on initial presentation. Other cases may progress much faster than four months.
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•• While conventional radiographs are fine (80% accurate) at detecting bone invasion with maxillary masses, they are three times less sensitive than CBCT in detecting invasion of adjacent structures, an important prognostic indicator [11]. Post‐procedure: it is essential to have pre‐ and post‐extraction radiographs [2]. A study of reported complete carnassial extractions in dogs and cats showed that tooth fragments remained in place 82–92% of the time [1].
COMMENTS ■■
It is not possible to practice appropriate veterinary dentistry without utilizing dental radiography.
See also the following chapters: Chapter 1 ■■ Chapter 7 ■■ Chapter 9 ■■ Chapter 16 ■■ Chapter 20 ■■ Chapter 27 ■■ Chapter 37 ■■ Chapter 40 ■■
Abbreviations ■■
■■
■■
CBCT = cone beam computed tomography HDVI = high‐definition volumetric imaging IRR = intentional (resorbing) root retention
■■ ■■ ■■ ■■ ■■
MET = modified extraction technique PDL = periodontal ligament SLOB = same lingual, opposite buccal TMJ = temporomandibular joint; TR = tooth resorption
References 1. Moore JI, Niemiec BA. Evaluation of extraction sites for evidence of retained tooth roots and periapical pathology. J Am Anim Hosp Assoc 2014;50:77–82. 2. Bellows J, Berg ML, Dennis S, et al. 2019 AAHA Dental Care Guidelines for Dogs and Cats. J Am Anim Hosp Assoc 2019;55(2):49–69. 3. Roza MR, Silva LAF, Barriviera M, et al. Cone beam computed tomography and intraoral radiography for diagnosis of dental abnormalities in dogs and cats. J Vet Sci 2011;12(4):387–392. 4. Niemiec BA. Oral radiology and imaging. In: Lobprise HB, Dodd JR, eds. Wiggs’s Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019:46, 48, 133, 240. 5. Heney CM, Arzi B, Kass PH, et al. The diagnostic yield of dental radiography and cone‐beam computed tomography for the identification of dentoalveolar lesions in cats. Front Vet Sci 2019;6:42. 6. Heney CM, Arzi B, Kass PH, et al. Diagnostic yield of dental radiography and cone‐beam computed tomography for the identification of anatomic structures in cats. Front Vet Sci 2019;6:58. 7. Hansen KS, Kent MS. Imaging in non‐neurologic oncologic treatment planning of the head and neck. Front Vet Sci 2019;6:90. 8. Bar‐Am Y, Pollard RE, Kass PH, Verstraete FJM. The diagnostic yield of conventional radiographs and computed tomography in dogs and cats with maxillofacial trauma. Vet Surg 2008;37(3):294–299.
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9. Martin‐Flores M, Scrivani PV, Loew E, et al. Maximal and submaximal mouth opening with mouth gags in cats: implications for maxillary artery blood flow. Vet J 2014;200(1):60–64. 10. Hale FA. Localized intrinsic staining of teeth due to pulpitis and pulp necrosis in dogs. J Vet Dent 2001;18(1):14–20. 11. Ghirelli CO, Villamizar LA, Pinto AC. Comparison of standard radiography and computed tomography in 21 dogs with maxillary masses. J Vet Dent 2013;30(2):72–76.
Author: Jennifer R. Mathis, DVM, CVPP Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Section
II
Techniques
47
Chapter
4
Complete Dental Cleaning INDICATIONS ■■ ■■
To remove deposits of plaque, calculus and debris from teeth. Another term, prophylaxis, is often used, but is less accurate as it implies prevention, which is the case only in cleaning teeth in stage 1 periodontal disease.
EQUIPMENT (see Chapter 9) ■■ ■■ ■■ ■■ ■■ ■■ ■■ ■■ ■■ ■■ ■■
Gloves, mask, eye protection Dilute chlorhexidine rinse (0.12%) Mouth wedge or gag Dental mirror Calculus forceps (Figure 4.1) Scaler (ultrasonic, sonic) (Figure 4.2) Hand scaler (Jacquette) Disclosing solution (optional) Slow speed polisher, prophy angle, prophy cup Polishing paste Fluoride (optional)
■■ Figure 4.1 Calculus forceps.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 49
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■■ Figure 4.2 Prophy paste, prophy angle, and ultrasonic scaling tip.
■■ Figure 4.3 Applying dilute chlorhexidine prior to starting the dental procedure.
PROCEDURE ■■ ■■
■■
■■
■■
General anesthesia with cuffed endotracheal tube, monitoring, and supportive care. Gently flush oral cavity with dilute chlorhexidine (Figure 4.3); avoid getting solution on nasal mucosa, especially in cats. Initial assessment to identify areas of significant disease that might require therapy, in particular those areas that were not apparent on the alert examination. •• Palatal aspect of maxillary canine – deep pockets. •• Pockets at either aspect of mandibular first molar. •• Any worn, chipped, fractured, or discolored teeth. Gently dislodge larger sections of calculus with calculus forceps; take care not to damage teeth (Figure 4.4). Use mechanized scaler (ultrasonic or sonic) to continue to remove gross deposits of calculus from crown surfaces.
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51
■■ Figure 4.4 Gently use the calculus forceps to dislodge large pieces of calculus.
■■ Figure 4.5 Use the side of the ultrasonic scaler head, not the tip.
■■
■■ ■■
Use side of scaler tip, not end (Figure 4.5). •• Use sufficient water spray for coolant; replace scaler stack if tip overheats. •• Apply side of scaler to individual tooth for no longer than 10–12 seconds at a time; return to the tooth later if additional scaling is necessary. •• Use the sharp tip of a hand scaler (Jacquette) to remove remaining deposits of calculus in grooves (upper fourth premolar development groove); do not use tip of ultrasonic scaler there (Figure 4.6). •• Use disclosing solution or air syringe to identify any remaining deposits of calculus. Complete examination, probing (Figure 4.7), and intraoral radiology (see Chapters 1–3). Additional therapy •• Periodontal pockets (see Chapter 5). •• Extractions as needed (see Chapters 6 and 7).
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■■ Figure 4.6 The sharp tip of a hand scaler can remove the remaining calculus in developmental grooves.
■■ Figure 4.7 Once the calculus is gone, use a probe to identify possible presence of pockets. ■■
■■
Polishing (Figure 4.8) •• Use proper speed (less than 3000 rpm), sufficient prophy paste, and moderate pressure to gently splay the foot of the prophy cup. •• Note: try the prophy cup on your fingernail; if it generates heat, adjust the speed, amount of paste, or pressure to a safer level. •• Polish each tooth surface, no more than 4–10 seconds per tooth. If further polishing is needed, continue to other teeth and return to this tooth for additional polishing later. Irrigation •• With air–water syringe or blunt‐tipped needle on syringe, rinse tooth surfaces and subgingival areas to remove any remnants of calculus or paste, which could cause a periodontal abscess if left (Figure 4.9). •• The air syringe can be used to gently dry the tooth surface (or in the pocket) to identify any calculus remnants (discolored or chalky) (Figure 4.10).
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53
■■ Figure 4.8 Use copious prophy paste and moderate pressure to splay the prophy cup foot, but not to excess.
■■ Figure 4.9 Thoroughly rinse the tooth surfaces.
■■ Figure 4.10 Air dry the tooth surfaces to visualize remaining calculus.
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Fluoride •• For additional antibacterial activity, and for remineralization and desensitization. •• When indicated (avoid in renal patients), apply acidulate phosphate fluoride to dry tooth surfaces and leave on according to manufacturer’s recommendation. •• Air blow or wipe off; rinsing deactivates most fluorides. •• Avoid allowing ingestion.
COMMENTS ■■
■■ ■■ ■■
This complete dental cleaning description deals with crown surfaces only. It is imperative to identify and treat any subgingival lesions thoroughly (see Chapter 5). Appropriate preoperative diagnostics when indicated prior to procedure. Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures.
See also the following chapters: Chapter 5 ■■ Chapter 6 ■■ Chapter 7 ■■ Chapter 9 ■■
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC, DVM, DAVDC
Chapter
5
Periodontal Pocket Therapy INDICATIONS ■■
■■
■■
To remove deposits of plaque, calculus, and debris from the tooth surfaces in periodontal pockets and gently debride the inner lining of the pocket. To further treat selected periodontal pockets with subgingival medicaments to enhance healing of the lesion. To manage soft tissue associated with periodontal pockets or adjacent to teeth that have been extracted to provide optimal periodontal health to the remaining teeth.
EQUIPMENT (see Chapter 9) ■■ ■■ ■■ ■■ ■■ ■■
Periodontal probe (Figure 5.1a) Hand curette and other debridement instruments (serrated periodontal elevators) W‐3 PFI (plastic filling instrument) – “beaver tail” Doxirobe™ gel (if available, or similar human product) Scalpel blade/handle Gingivoplasty and soft tissue debridement implements: serrated periosteal elevator, crown and collar scissors, 12‐fluted burs (Figure 5.1b)
(a)
(b)
■■ Figure 5.1 (a) Periodontal probe, hand curette (with round end), and W‐3 beaver tail for packing perioceutic. (b) Gingivoplasty and soft tissue debridement implements: serrated periosteal elevator, crown and collar scissors, 12‐fluted burs.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 55
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PROCEDURE ■■ ■■
■■
Provide preoperative and intraoperative (local) analgesia where appropriate. Some soft tissue periodontal pockets may be due to chronic minor gingival enlargement, or bone loss with decreased attachment levels. •• If there is sufficient attached gingiva remaining, a simple gingivoplasty of excess or inflamed gingival margin can immediately reduce the pocket depth. •• A 12‐fluted bur (finishing bur) can be used to gently remove the excess tissue and provide a contoured feathered edge to the gingival margin (Figure 5.2). Identify and select periodontal pockets of appropriate depth for additional therapy (3–5 mm) (Figure 5.3). •• These are moderate depth, supra‐bony, soft tissue pockets. •• Deeper soft tissue pockets (greater than 5 mm) would require performing a gingival flap to open the site for adequate cleaning (open root planning).
■■ Figure 5.2 Use of a 12‐fluted bur to recontour areas of mild gingival enlargement, surgically reducing the pocket depth.
(a)
(b)
■■ Figure 5.3 (a) Probe inserting into periodontal pocket (5 mm in depth). (b) Probe placed at the 5‐mm mark on top of the gingiva to indicate the depth of the pocket.
chapter 5 Periodontal Pocket Therapy
■■
■■
■■
57
•• Deeper infra‐bony pockets (with vertical bone loss) would require more advanced periodontal procedure with gingival flap for access, complete curettage of infra‐bony pocket, and placement of material to encourage bone regrowth. Select appropriate hand curette: curettes have a round toe at the end and rounded back (in cross‐ section, they have a half‐moon shape and a flat edge, which is the face of the instrument). •• Curettes are double‐ended: the two ends are mirror images of each other, as only one side will contact tooth surface for root planing. •• Curette working ends are numbered (e.g. 11/12), with varying angulations (designed in human dentistry to clean specific tooth surfaces). Some equipment companies have specialized veterinary curettes (feline). •• Size of working ends can also vary: some smaller types (mini) may be useful for instrumentation in periodontal pockets of small dogs and cats. Insert curette head into depth of pocket, adjusting the cutting edge to contact the tooth surface (closed face) (Figure 5.4). With a pull stroke, bring curette edge down the surface of the root, dislodging calculus and debris. Use this pull stroke in several different directions in a cross‐hatching pattern to effectively root plane the surface free from debris (Figure 5.5).
(a)
(b)
■■ Figure 5.4 (a) Working edge of the curette placed against the tooth surface. (b) Curette advanced into depth of the pocket.
■■ Figure 5.5 With a pull stroke down, calculus and debris in the pocket can be debrided (this is demonstrated in a specimen, so no bleeding is present, as would be the case in a patient).
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■■
■■
■■
■■
SECTION II TECHNIQUES
As the surface is cleaned of debris, the tactile (and auditory) sensation will go from a rough feel to a smooth feel. With light digital pressure on the external surface of the pocket, allow the opposite edge of the curette to gently debride the diseased soft tissue (subgingival curettage or debridement). There will be moderate hemorrhage. Some (not all) ultrasonic units are made to allow subgingival cleaning, which allows cavitation of bacteria in addition to scaling. •• Other ultrasonic scalers should not be used below the gumline, as once the tip is buried the water spray cannot adequately cool the tip, potentially causing overheating and damage to tooth. Polish the crown surface and gently splay the foot of the prophy cup to polish a millimeter or two of the root surfaces (Figure 5.6). Irrigate then air dry the area thoroughly to remove any remnants of calculus, debris, or prophy paste (Figure 5.7).
■■ Figure 5.6 The prophy cup foot is splayed to polish the root surface of the pocket.
■■ Figure 5.7 After irrigating all debris and prophy paste off the tooth, a gentle blast of air into the sulcus helps dry the area and shows clean surfaces.
chapter 5 Periodontal Pocket Therapy
■■
■■
■■
59
Prepare the perioceutic according to manufacturer’s recommendations. •• Introduce the material into the pocket, following manufacturer’s instructions. •• Note: there are other perioceutics used in human dentistry and other products with clindamycin. •• Homecare: oral solutions or gels may be used initially, but the owner should not brush for 14 days. Recheck at two weeks to assess healing and start brushing at that time. •• Prescribe antibiotics and pain medication postoperatively as appropriate. •• Recheck and re‐treat in five months. Treat interdental periodontal pockets with planned extraction(s) of one of the teeth. For example, mandibular third incisor extraction to treat canine; mandibular fourth premolar or second molar extraction to treat first molar. Removal of persistent or redundant tissue that is forming pockets (mandibular canines). •• For descriptive purposes, images are provided to show how excess or redundant tissue will be excised from the mesial aspect of a mandibular canine tooth to manage the soft tissue and reduce the pocket depth (Figure 5.8). •• Make a reverse bevel incision into the interdental or mesial/proximal tissue, extending from the mesial aspect of 304, through the redundant tissue both buccally/labially and lingually, preserving a collar of attached gingiva (Figure 5.9). This would extend to the mesial aspect of third incisor for its extraction flap. If this incision is made to incorporate the extraction of 301, 302, 303, it can be termed a “wedge” excision. •• Use a blade to make a sulcular incision around the tooth/teeth to be extracted (403 plus), and at the mesial aspect of 304 if the pocket affects the canine (second incision). •• Using crown and collar scissors, curettes, or serrated periosteal elevator, debride the pocket lining and redundant tissue as the 403 is elevated or excess tissue removed (Figures 5.10 and 5.11). •• Further debride the now accessible area adjacent to 304, including open root planing and ultrasonic scaling of the tooth/root surface. If an infra‐bony pocket between 304 and bone is present, a bone graft material can be used. •• Suture the healthy gingival margins, with care at the mesial aspect of 404; this closure may be located further apically on the tooth, with resultant root exposure, but the pocket will be minimized (Figure 5.12).
■■ Figure 5.8 Area of redundant tissue between mandibular canines after incisors have been lost; deep pockets are present.
■■ Figure 5.9 Make a reverse bevel incision into the proximal tissue, extending from the mesial aspect of 304, through the redundant tissue both buccally/labially and lingually, preserving a collar of attached gingiva.
■■ Figure 5.10 Using crown and collar scissors or curettes, debride the pocket lining and redundant tissue.
■■ Figure 5.11 Further debride the now accessible area adjacent to 304, using a serrated periosteal elevator to remove granulation tissue, and including open root planing and ultrasonic scaling of the tooth/root surface.
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■■ Figure 5.12 Suture the healthy gingival margins with care at the mesial aspect of 304. This closure may be located further apically on the tooth, with resultant root exposure, but the pocket will be minimized.
COMMENTS ■■ ■■ ■■
■■ ■■ ■■ ■■
Blunt or dull curettes will be ineffective in root planing; keep instruments sharpened. Using the perioceutic without effective root planing will have poor results. Attempting to root plane or treat a pocket deeper than 5 mm without using a gingival flap will be ineffective. Excessive pressure when root planing can damage the root surface. Appropriate preoperative diagnostics when indicated prior to procedure. Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures.
See also the following chapters: Chapter 4 ■■ Chapter 9 ■■ Chapter 20 ■■
Abbreviation ■■
PFI = plastic filling instrument or W‐3
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
6 Gingival Flaps
INDICATIONS ■■
To access site for effective treatment. •• Extraction site: ◦◦ Flap design is discussed in this chapter; additional extraction steps discussed in Chapter 7. ◦◦ Interdental periodontal pocket treatment with extractions (see Chapter 5). •• Periodontal surgery of deep pockets (greater than 5 mm).
EQUIPMENT (see Chapter 9) ■■ ■■ ■■ ■■
15C scalpel blade (see Figure 6.1a) Periosteal elevator (Molt #2 and/or #4) (Figure 6.1a) Tissue forceps Small scissors (Figure 6.1b)
(a)
(b)
■■ Figure 6.1 (a) 15C scalpel blade, scalpel handle, Molt #2 periosteal elevator, Molt #4 periosteal elevator. (b) Thumb forceps, needle holders, and small sharp scissors.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 62
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PROCEDURE ■■ ■■
Adequate pain management: preoperative, multimodal, local blocks and postoperative dispensing. Appropriate antimicrobial selection.
Flaps for Extraction ■■
General concepts •• Adequate exposure is necessary to facilitate extraction procedure and flap closure afterward. •• Full‐thickness mucoperiosteal flap is typically used. •• Flap should extend through attached gingiva, past mucogingival line, into alveolar mucosa, typically at the mesial and/or distal aspects of the tooth, in the interdental area (Figure 6.2). •• Freshen the edge of the gingival margin with the blade by removing 1 mm before the flap is elevated (Figure 6.3). •• Introduce the blade tip into the sulcus around the tooth to release the junctional epithelium at the base of the sulcus (Figure 6.4). •• Elevate flap with periosteal elevator, to the level of the alveolar mucosa (Figure 6.5a–c).
■■ Figure 6.2 Releasing incisions are full thickness, extending through the attached gingiva, past the mucogingival junction into the alveolar mucosa above (right maxillary canine).
■■ Figure 6.3 The blade can be used to freshen the gingival margin edge before elevation (right maxillary canine).
64 SECTION II TECHNIQUES
■■ Figure 6.4 The tip of the blade can be introduced into the sulcus to release the junctional epithelium around the tooth (right maxillary fourth premolar).
(a)
(b)
(c)
(d)
■■ Figure 6.5 (a) The periosteal elevator is introduced at the edge of the flap, to elevate it full thickness (right maxillary canine). (b) Elevation is continued, working the periosteal elevator along the length of the flap (right maxillary fourth premolar). (c) Elevation is continued until the flap is released to the level past the mucogingival junction. (d) Elevation of the lingual or palatal mucosa can be done after tooth extraction, before suturing (right mandibular first molar).
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•• Gently elevate or stretch the palatal or lingual gingiva as well (Figure 6.5d); this is sometimes more easily done once the tooth is extracted. •• Release tension on flap by excising periosteal layer on underside of flap (Figure 6.6a): pull up on flap with forceps, and gently excise periosteal fibers until release is apparent (Figure 6.6b). Do not go through full thickness. •• After the extraction, close flap with absorbable suture, using simple interrupted pattern. Maxillary canines •• Make mesial (rostral) incision in a direct dorsal direction (see Figure 6.2). •• Make distal incision angled caudally, following the direction of the root (Figure 6.7). Note: while there may be concerns about a distal incision interfering with blood supply to the flap, extensive personal experience has shown this not to be the case, particularly with broad‐based flaps. •• It is essential on this tooth to provide release by excising periosteal fibers, especially if an oronasal fistula is present.
(a)
(b)
■■ Figure 6.6 (a) The periosteal fibers on the underside of the flap must be gently excised to remove tension on the flap (maxillary canine). (b) Once the fibers are excised, the flap can be extended easily, so that when it is sutured there will be no tension (maxillary fourth premolar).
■■ Figure 6.7 After the mesial (rostral) incision is made, a distal incision, angled distally to follow the root, is made (maxillary canine).
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■■
■■
■■
■■
Maxillary fourth premolar •• Mesial (rostral) incision is typically sufficient to release the flap; a distal incision may damage salivary ducts (see Figures 6.4 and 6.5b). •• At closure, the corner of the mesial incision edge will rotate to fit into the space of the palatal root (Figure 6.8). Mandibular canine •• Start incision at distal aspect of canine for 2–3 mm, following the linguo‐distal direction of the root (Figure 6.9). •• At the caudal extent of the first incision, make buccal and lingual releasing incisions, in a Y pattern (Figure 6.10a); avoid cutting through the frenulum (fold of mucosa on buccal aspect) (Figure 6.10b). •• Additionally, an incision at the mesial (rostral) aspect of the tooth can be made for additional release (Figure 6.11a,b). •• Elevation of the lingual mucosa gives access for bone removal and elevation (Figure 6.11c). Mandibular first molar •• Make distal and mesial incisions (Figure 6.12). •• Once the tooth is extracted, gently elevate the lingual gingival margin sufficiently to provide release for adequate closure (see Figure 6.5d). Envelope flaps: for minor extractions that need minimal access, use the periosteal elevator to gently stretch out the gingival margins, without a releasing incision, and which can later be sutured at closure (Figure 6.13).
■■ Figure 6.8 With proper release, the mesial corner of the flap can be rotated (after tooth extraction) to be sutured near the site of the palatal root (maxillary fourth premolar).
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■■ Figure 6.9 An incision is made at the distal aspect of the mandibular canine, following the line of the root as it is positioned medially/lingually.
(a)
(b)
■■ Figure 6.10 (a) At the caudal extent of the first incision, a Y‐shaped incision pattern with lingual and buccal/ labial releasing incision can further provide access to the alveolar bone at the distal aspect of the tooth. (b) Extension of the buccal releasing incision, while preserving the frenulum, allows creation of a full buccal flap.
(a)
(b)
(c)
■■ Figure 6.11 An incision at the mesial (rostral) aspect of the mandibular canine will allow better access with a full buccal flap. (a) An incision is made at the mesial aspect of the tooth. (b) The buccal flap is elevated. (c) The lingual flap is elevated.
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(a)
(b)
■■ Figure 6.12 (a) Distal releasing incision of right mandibular first molar. (b) Mesial (rostral) releasing incision of right mandibular first molar.
■■ Figure 6.13 Envelope flap to provide access without releasing incisions.
Flaps for Interdental Periodontal Pocket Therapy (see Chapter 5) ■■
■■
An inverse bevel incision is used across the interdental space to incorporate the tooth to be extracted (e.g. 403) and the tooth to be treated (404) – buccal and lingual. A wedge incision is used to incorporate tissue mesial to a strategic tooth, such as mandibular canine with several incisor extractions.
Flaps for Periodontal Surgery ■■
■■
If a periodontal pocket is greater than 5 mm, closed root planing will be challenging and ineffective, so a gingival flap will expose the site for adequate treatment. As compared to extractions with interdental releasing incisions, the gingival margin around the tooth to be periodontally treated should be preserved. •• Releasing incision should be made at the adjacent tooth, at the “line angle” (Figure 6.14): ◦◦ Halfway between the outside aspect of the tooth and the midpoint of the root, i.e. the line angle. ◦◦ Not interdentally. ◦◦ Not at the furcation. •• Not directly over the midpoint of the root.
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■■ Figure 6.14 For periodontal therapy, the releasing incision will be made at the line angle of an adjacent tooth.
■■ Figure 6.15 The interdental release is made at the lingual aspect of the mandibular incisors to preserve the interdental gingiva.
•• When there is interdental gingiva (col, papilla) between teeth and the flap is to be made across several teeth, incise the interdental gingiva lingual or palatal to the teeth, not directly over the height of the papilla (Figure 6.15). •• Specially designed flaps, such as a crescent‐shaped flap at the palatal aspect of a maxillary canine, will expose the site for effective treatment of deep infra‐bony pockets that have not yet progressed to oronasal fistula. Note: Attention is paid to the palatal artery to preserve it within the flap. •• Elevate with periosteal elevator only as much as is needed to expose the area to be treated. Note: One exception is to elevate through the attached gingiva to the level of the alveolar mucosa if the flap is to be sutured so the gingiva is placed further apically down the root (apically repositioned flap, ARF). This procedure is used to minimize soft tissue pocket depth and maximize contact between the remaining attached gingiva and bone.
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Closure of Flaps ■■ ■■ ■■ ■■
Small, absorbable suture material used in a simple interrupted pattern is typically best. In dogs, a small reverse cutting needle will help penetrate the tough gingiva best. In cats, a small taper needle may cause less trauma, especially in inflamed tissues. With the palatal or lingual mucosa also elevated, pass needle/suture through this tissue first, then through buccal mucosal flap.
COMMENTS ■■
■■
■■
■■ ■■ ■■
Without flaps, certain treatments would be ineffective (root planing of deep pockets), or cause trauma to the patient (extraction without exposure for tooth sectioning or alveolar bone removal). Proper instruments and technique are essential; rough handling of delicate or inflamed tissues could lead to loss of tissues and/or failure of the procedure. Failure to adequately release the tension of the flap (by resecting the periosteum on the underside of the flap) is a common reason for failure to close, especially in closing oronasal fistulas, where constant tension from respiratory movement is present. Appropriate preoperative diagnostics when indicated prior to procedure. Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures.
See also the following chapters: Chapter 5 ■■ Chapter 7 ■■ Chapter 9 ■■
Abbreviation ■■
ARF = apically repositioned flap
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
7
Extraction Technique
INDICATIONS ■■
■■
Cause for extraction •• Periodontal disease. •• Endodontic disease: exposed canal; nonvital pulp; poor transillumination; periapical bone loss. •• Tooth resorption. •• Persistent deciduous teeth. •• Supernumerary, crowded, or maloccluded teeth. Decision process criteria •• Tooth: strategic vs. nonstrategic; relative importance of tooth compared to extent of therapy necessary to save it; extent of disease. •• Patient: underlying systemic considerations may lead to decision to extract a tooth, compared to additional efforts at periodontal therapy with frequent anesthetic episodes, chance of persistent inflammation, etc. •• Client: more advanced therapy will need a commitment for additional cost, home care, and follow‐up visits, as compared to extraction resolving the problem.
EQUIPMENT (see Chapter 9) ■■ ■■
Instruments for gingival flap (see Chapter 6). Means of sectioning teeth and removing or smoothing alveolar bone (alveoloplasty). •• Power equipment ◦◦ High‐speed handpiece on air‐driven unit. ◦◦ Contra‐angle gear on slow‐speed handpiece (micromotor unit) set on highest speed possible. •• Cutting burs ◦◦ Crosscut fissure bur for sectioning teeth (#699, #700, #701). ◦◦ Round bur for gross alveoloplasty (#2, #4, #6). ◦◦ Diamond bur for finishing alveoloplasty. •• Dental elevators (Figure 7.1) ◦◦ Various sizes and shapes. ◦◦ Sharpened edge: elevators must be sharpened on a regular basis to allow the edge to fit in the periodontal ligament space between tooth and alveolar bone. •• Extraction forceps (Figure 7.1).
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 71
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■■ Figure 7.1 Dental extraction forceps, winged dental elevator, and crosscut fissure bur on high‐speed handpiece.
■■ Figure 7.2 Using a round bur on a high‐speed handpiece, alveolar bone may be removed for better access for sectioning at a furcation.
PROCEDURE ■■
General steps: for details, see individual descriptions. •• Adequate pain management: preoperative, multimodal local blocks and preoperative dispensing. •• Appropriate antimicrobial selection. •• Appropriate patient monitoring and support during anesthetic procedures. •• Access (see Chapter 6). •• Alveolar bone removal to access furcation or expose wide root structure (canines) (Figure 7.2). •• Section multirooted teeth with crosscut fissure bur, using bur flat on tooth, moving from furcation down through the crown (shortest distance) (Figure 7.3). When using slow‐speed handpiece, have assistant drip water onto site to reduce heat buildup.
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■■ Figure 7.3 A crosscut fissure bur on a high‐speed handpiece is used with the length of the bur against the tooth for optimal cutting.
■■ Figure 7.4 A dental elevator, with its tip sharpened, is carefully advanced into the periodontal ligament space in between the tooth and alveolar bone.
•• Elevation ◦◦ Position dental elevator: ⋄⋄ In periodontal ligament space: advance tip of dental elevator in between tooth root and bone (Figure 7.4). With sharpened tip, take great care and have controlled use of the elevator with the tip just past your finger and advance with caution to avoid slipping. ⋄⋄ In between root section crowns, with care (Figure 7.5). ⋄⋄ Between crown/root section and adjacent tooth: be careful not to loosen adjacent tooth (Figure 7.6). ◦◦ Adjustment (rotation or other movement) of instrument to contact and push the tooth root to stretch and fatigue periodontal ligament (Figure 7.7). ◦◦ Remove root segments with dental extraction forceps (Figure 7.8); if not ready to be removed, with gentle rotation of the forceps, determine where further elevation is needed, or remove additional bone. ◦◦ Debride/curette alveolus of debris with serrated periosteal elevator (Figure 7.9).
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■■ Figure 7.5 A dental elevator can be used with controlled force between crown sections.
■■ Figure 7.6 A dental elevator can be used between a tooth segment to be elevated and an adjacent tooth, taking care not to loosen the adjacent tooth.
■■ Figure 7.7 The dental elevator can be rotated after placement to stretch and fatigue the periodontal ligament.
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■■ Figure 7.8 Once the periodontal ligament is completely fatigued, and the tooth is loose, it can be grasped with the extraction forceps and gently removed from the alveolar socket.
■■ Figure 7.9 After the tooth has been removed, gently curette the alveolus to remove any debris or infected tissue.
■■
◦◦ Smooth rough bony spicules on alveolar margin using round bur (alveoloplasty); then finish and smooth the surfaces with a diamond bur (Figure 7.10). ◦ ◦ Place osseopromotive substance in select sites to support osseous healing (optional). ◦◦ Suture: nonabsorbable, simple interrupted sutures or cruciate. Uncomplicated elevation •• Access/exposure with envelope flap or simple releasing incisions (see Chapter 6) (Figure 7.11). •• Section multirooted teeth with crosscut fissure bur (Figure 7.12). •• Elevate root segments to loosen; remove with extraction forceps. •• Debride socket; alveoloplasty. •• Suture.
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■■ Figure 7.10 Any rough edges of alveolar bone should be reduced and smoothed prior to flap closure.
■■ Figure 7.11 Envelope flap for simple exposure without releasing incisions.
■■ Figure 7.12 Use a small crosscut fissure bur (#699) to section a feline mandibular third premolar.
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Maxillary canine •• After the gingival flap is elevated, use round bur to make a groove at the mesial (rostral) and distal aspects of the canine for 3–4 mm. •• Using round or crosscut fissure bur, remove 2–3 mm of buccal alveolar bone plate (Figure 7.13) to extend the alveolar opening to a location at the widest part of the root. •• Elevate and remove tooth or tooth root segments, debride socket, perform alveoloplasty, and then suture. •• If tooth does not loosen sufficiently initially, additional buccal bone removal may be necessary. •• Be careful not to elevate aggressively on the palatal aspect, or rotate the root in that direction, as an iatrogenic oronasal fistula may occur. Maxillary fourth premolar •• After the gingival flap is elevated, use round or crosscut fissure bur to remove crestal alveolar bone to expose furcation, and use crosscut fissure bur to section tooth between the mesiobuccal and distal roots, cutting through to the developmental groove (Figure 7.14a). A second cut is made from the furcation mesially to remove a triangular piece of tooth that will facilitate visualization of the furcation between the two mesial roots (Figure 7.14b).
■■ Figure 7.13 Grooves can be made in the alveolar bone at the mesial (rostral) and distal aspects of the tooth to facilitate placement of the dental elevator. With a furrow made between the grooves, a few millimeters of alveolar bone can be removed from the buccal surface of the maxillary canine to provide an opening as wide as the root itself.
(a)
(b)
■■ Figure 7.14 (a) The crosscut fissure bur is used from the buccal furcation of the upper fourth premolar through the crown, to the developmental groove. (b) A second section from the furcation rostrally will remove a triangular piece of crown that will allow visualization of the furcation between the two mesial roots.
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(a)
SECTION II TECHNIQUES
(b)
■■ Figure 7.15 (a) Begin to section through the two mesial roots (buccal and palatal) at the rostral midpoint of the tooth. (b) Extend the sectioning to join the first furcation cut.
■■ Figure 7.16 A section of the distal aspect of the distal crown can be removed to provide space for the dental elevator.
•• Use the crosscut fissure bur to section the tooth between the two mesial (buccal and palatal) roots at the furcation (Figure 7.15). •• With the crosscut fissure bur, remove the distal aspect of the distal crown to provide space for dental elevator between the premolar and molar (Figure 7.16). •• If one root is removed, and the others are still solid, you can remove additional bone in between the roots to better access the remaining roots. Preserve as much buccal cortical bone as possible. •• Keep the interseptal bone in place initially to help elevate the palatal root out. If the palatal root tip is broken off and retained, use the crosscut fissure bur in the alveolus coronal to the root tip in a funnel‐shaped action to allow easier access and elevation (Figure 7.17). •• If a buccal root tip is broken off and retained, further elevate the soft tissue to expose the jugae over the root, and use the crosscut fissure bur in a “windshield wiper” action to remove the buccal bone over the root to expose it for further elevation. •• Elevate and remove tooth segments, debride socket, perform alveoloplasty, and suture (Figure 7.18). •• Do not use the burs to “pulverize” root tips out; infected debris can be forced into deeper tissues and the root tips may even go into the nasal cavity.
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■■ Figure 7.17 If the palatal root is not easily elevated, or root tip is fractured, remove bone from the walls of the alveolar socket to allow better access.
■■ Figure 7.18 Smooth the roughened edges of alveolar bone before suturing (alveoloplasty).
■■
Mandibular first molar •• After the gingival flap is elevated, use round or crosscut fissure bur to remove crestal alveolar bone to expose furcation, and use crosscut fissure bur to section tooth between the roots, cutting through to distal aspect of the mesial crown (Figure 7.19). •• Make a second cut through the tooth from the furcation mesially to remove a diamond‐shaped piece of crown, exposing access to the roots (red line in Figure 7.19). •• With the crosscut fissure bur, remove the distal aspect of the distal crown, and shave off the mesial aspect of the crown to provide space for dental elevator between the molar and the adjacent teeth (Figure 7.20). •• Often the distal root will elevate more easily. Once removed, use a round bur at this point to remove cancellous bone behind the mesial root to provide better access for the elevator; avoid removing buccal cortical bone when possible, as it provides strength
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■■ Figure 7.19 The lower first molar is sectioned with the crosscut fissure bur, starting at the furcation and cutting through in front of the distal cusp. A second cut can be made through the tooth from the furcation mesially to remove a diamond‐shaped piece of crown (red line), exposing access to the roots.
■■ Figure 7.20 The distal root of the lower first molar is elevated.
■■
for the mandible (Figure 7.21). Note: The mesial root can be one of the most difficult ones to remove, due to its size and a groove on its distal aspect that can discourage rotation and elevation (Figure 7.22). •• Elevate and remove tooth segments, debride socket, perform alveoloplasty, consider packing with osseopromotive material, and suture. Mandibular canine •• After the gingival flap is elevated from the buccal, distal and lingual surfaces, use round or crosscut fissure bur to remove a crescent‐shaped area of bone from the distal‐ lingual aspect of the tooth (Figure 7.23) and make a groove at the mesial aspect of the tooth to help elevator placement (Figure 7.24). •• Before elevating, assess the degree of mandibular symphysis laxity/movement, if any present (not uncommon in small dogs and cats), and record on chart. •• Elevate carefully while supporting the mandible with the opposite hand. Evaluate integrity of symphysis and adjacent teeth (third incisor, first premolar) on a regular basis. Elevate at the distal aspect of the tooth, following the line of the root lingually
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■■ Figure 7.21 Once the distal root is gone, cancellous bone at the distal aspect of the mesial root can be removed for better elevator access. Preserve the buccal cortical plate when possible.
■■ Figure 7.22 A groove on the distal aspect of the mesial root can make elevation challenging.
■■ Figure 7.23 Once the Y‐shaped flap at the distal aspect of the canine is raised, remove a crescent‐shaped area of bone at the distal aspect of the mandibular canine to provide sufficient access to elevate the broad root.
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■■ Figure 7.24 A groove may be made at the mesial aspect of the mandibular canine for elevator placement but preserve as much cortical bone as possible.
(a)
(b)
■■ Figure 7.25 (a) Elevation of the distal aspect of the tooth should follow the line of the root lingually. (b) As you elevate at the mesial aspect of the canine, follow the curve of the tooth downward and medially, and try to protect the lower third incisor.
■■
(Figure 7.25a) and at the mesial aspect of the tooth, following the root (Figure 7.25b). •• Remove tooth, debride socket, perform alveoloplasty, consider placement of osseopromotive substance, and suture. With adequate flap release, there should be no tension when the buccal flap is extended over the defect for suturing (Figure 7.26). •• If the tooth does not loosen sufficiently, additional bone may be removed, but be careful with the mental foramen buccally and subgingival tissues lingually. Tooth resorption (see Chapter 40) •• If a tooth has been diagnosed as a true odontoclastic resorptive lesion with no visible distinction between tooth and bone (periodontal ligament space obliterated, tooth root converting into osseous tissue), then a modified extraction technique may be considered. Note: the term “crown amputation” might not be a favorable term to use with clients.
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■■ Figure 7.26 With proper flap procedures, the site should be closed without tension.
•• Follow all steps of local analgesia, flap (envelope), sectioning tooth (if multirooted). •• Begin elevation: the tooth crown will usually snap off (premolars). Some canine teeth will not be easily removed and crown amputation may be necessary in these cases to avoid traumatizing the mandible. •• Continue removal of remaining crown and smooth any remaining tooth edges or bony spicules. •• Suture site closed (cruciate suture). •• Record: odontoclastic resorption, modified technique; monitor for any persistent inflammation. •• Radiographs are essential! Some teeth with lesions that externally look like odontoclastic may have intact root roots that must be elevated.
COMMENTS ■■ ■■
■■ ■■ ■■
Extraction techniques should be sequential and deliberate, using patience. Rushing a procedure or using too much force can result in: •• Broken root tips •• Broken jaws •• Instruments slipping into other tissues (eyes, etc.). Appropriate preoperative diagnostics when indicated prior to procedure. Appropriate antimicrobial and pain management therapy when indicated. Do not use the burs to “pulverize” root tips out; infected debris can be forced into deeper tissues and the root tips may even go into the mandibular canal.
See also the following chapters: Chapter 6 ■■ Chapter 9 ■■ Chapter 40 ■■
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
8 Oral Pain Management
INDICATIONS ■■
■■
■■
Pain is the fourth vital sign [1–3]; however, with dental patients, pain is often overlooked [4] or unseen/hidden. Pain is a condition experienced by all mammals [2]. The range of behavioral disturbances present with chronic pain in dogs is similar to that experienced by humans [5], providing further evidence that our pets often experience the same pain as people. Since we know that dental pain hurts people, we must not ignore the fact that dental problems hurt our veterinary patients as well. The best way to treat pain is with multimodal analgesia. This means using multiple categories of drugs acting on different parts of the pain pathway (Figure 8.1). •• Transduction: site of injury or incision in the periphery. •• Transmission: signal from periphery to the spinal cord.
■■ Figure 8.1 The pain pathway.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 84
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•• Modulation: peripheral nerves synapse in the dorsal horn of the spinal cord, or the oral version, the nucleus caudalis in the medulla [6]. •• Perception: dorsal horn and nucleus caudalis signals are projected to the cerebral cortex.
EQUIPMENT: MATERIALS Categories of Drugs Opioids All opioids are not equal, as they may act differently according to the individual and species [7,8] as well their receptor activity (agonist, partial/mixed agonist, antagonist). A constant rate infusion (CRI) is a good way to tailor individual needs and responses to dose administration. The full μ (mu) agonists are the most effective for pain control. Opioids should be used routinely as premedication in combination with a tranquilizer/sedative [1,8]. ■■ Morphine: 0.1–1 mg/kg every 4–6 hours dogs; 0.1–0.2 mg/kg every 3–6 hours cats (not SQ). •• CRI: 0.1–0.36 mg/kg/h dogs; 0.05–0.1 mg/kg/h cats. •• CRI loading dose 0.1(cats)–0.5 (dogs) mg/kg IM, slow IV. •• Full μ agonist. ■■ Hydromorphone: 0.1–0.2 mg/kg dogs; 0.05–0.1 mg/kg cats (not SQ). •• CRI: 0.02–0.03 mg/kg/h; loading dose 0.05–0.1 mg/kg IM or IV. •• Full μ agonist. •• Similar potency to morphine. ■■ Fentanyl: 0.005–0.01 mg/kg every 0.5–2 hours, but preferred as CRI. •• CRI: 0.002–0.005 mg/kg/h; loading dose 0.002–0.003 mg/kg IM or IV. •• Full μ agonist. •• Much more potent than morphine. •• Short duration beneficial for quick CRI dose adjustment to individual response. •• Transdermal patch begins working in 6–12 hours (cat) or 18–24 hours (dog) [6,7]. ◦◦ Variability in absorption: poor to profound [7]. ◦◦ Risk of abuse or ingestion adds to the reasons to avoid using transdermal patches. ■■ Buprenorphine: 0.01–0.04 mg/kg every 4–8 hours dogs; 0.01–0.02 mg/kg IV, IM, OTM every 4–12 hours cats. •• Partial μ agonist. •• Greater affinity to μ receptor may result in less effective or ineffective full μ‐agonist administration in nearby time periods [7]. •• Add to bupivacaine for 24–72 hour analgesia post procedure [9,10] (see Table 8.1). •• Sustained‐release buprenorphine injection (SimbadolTM, Zoetis) 1.8 mg/ml: 0.24 mg/kg SQ s.i.d. for up to three days. TABLE 8.1 Block volumes. Lean weight of dog
Volume of local block
0.3 mg/ml buprenorphine
0.5% bupivacaine
20 kg
0.25–0.4 ml per oral sitea
0.1 ml
1.0–2.9 mla
Note: Use a 1‐ml or 3‐ml syringe to draw up the bupivacaine, add the buprenorphine, and replace with a 25G 1–1.5 inch needle. Always aspirate before administering to check for unintentional vascular entry. a Extra volumes not delivered to specific nerves can be given in soft tissues adjacent to treatment areas.
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Butorphanol: 0.2–0.6 mg/kg IM. •• μ antagonist/κ (kappa) agonist; mixed agonist. •• Use to reverse the effects of full μ agonists. •• Provides minimal to short analgesia. •• Sedating; antiemetic effect [7]. Naloxone: 0.001–0.04 mg/kg IV. •• Antagonist used to reverse opioid effects.
Alpha‐2 Agonists The α2 agonists result in sedation and analgesia. They are best combined with opioids for synergistic benefits, as both receptors are located in the same areas. ■■ Dexmedetomidine: 2–10 μg/kg IM. •• Lower doses minimize cardiovascular effects, but also produce shorter analgesia [1]. •• Reversible with equal volumes of atipamezole. •• Concurrent lidocaine CRI 3 mg/kg/h reduces the increase in systemic vascular resistance induced by dexmedetomidine, thereby increasing heart rate and cardiac index [11]. •• Important to measure blood pressure (BP), end‐tidal CO2 (ETCO2), oxygen saturation (SpO2), and EKG. Local Anesthetics These block transmission of the pain signal to the central nervous system (CNS) resulting in complete analgesia (Figure 8.2). They can also allow a decreased vaporizer setting, decreasing anesthetic risks with improvements in BP, heart rate, and respiratory rate. Combining local anesthetics with opioids can potentially double the effectiveness [6] and reduce inhalant needs [8–10]. Their safety and benefit necessitate their use in every surgical procedure. ■■ Bupivacaine: 1–2 mg/kg dogs; 0.5–1 mg/kg cats. •• Onset of action 2–5 minutes. •• Duration of anesthesia 6–8 hours. •• Addition of 0.03 mg buprenorphine per patient to bupivacaine extends analgesia 24–72 hours [9,10]. •• Addition of 1 μg/kg dexmedetomidine in block extends action by 3.5–8 hours [9,10].
■■ Figure 8.2 Analgesia is most effective when administered prior to surgical stimulation.
■■
■■
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Bupivacaine liposome injectable suspension (BLIS; Nocita®, Elanco): 5.3 mg/kg dogs; 10.6 mg/kg cats. •• Onset of action 2–5 minutes. •• Duration of action: up to 72 hours. •• Liposomal release is gradual, resulting in lower risk of adverse events. •• Long action provides at‐home analgesia, convenience, and known compliance. •• When sterile technique is used, vials can be used extra label in a multidose fashion for up to four days [12]. Lidocaine: 4–6 mg/kg dogs; 2–4 mg/kg cats. •• Onset of action 1–2 minutes. •• Duration 60–120 minutes. •• Systemic administration (2 mg/kg IV dogs; 0.25–0.5 mg/kg IV cats; best followed by 0.6–3 mg/kg/h CRI; 2 mg/kg IV loading dose; limit cats to 1.5 mg/kg/h) can improve the anesthetic‐sparing effects of local blocks [1,8], increase the heart rate for patients receiving dexmedetomidine [11], and potentially add cytoprotective benefits. •• Consider total dose volume when adding systemic administered and local dosed amounts of all types of local anesthetics not exceeding 10 mg/kg in dogs [9,10]. •• Mixing lidocaine and bupivacaine in the same syringe does not gain significant time to onset and decreases the duration over bupivacaine alone.
Nonsteroidal Anti‐inflammatory Drugs (NSAIDs) Best used prior to stimulus/tissue manipulation (see Figure 8.2). Opioids in combination with NSAIDs in people allow a 20–30% reduction in opioids [6]. ■■ Carprofen (Rimadyl®, Zoetis): 2 mg/kg b.i.d. or 4 mg/kg s.i.d. •• Shortest half‐life. ■■ Meloxicam (Metacam®, Boehringer Engelheim): 0.2 mg/kg s.i.d. loading dose followed by 0.1 mg/kg s.i.d. •• Liquid is convenient for administration after oral surgery. •• Black box warning in cats. ■■ Robenacoxib (Onsior®, Elanco): 1 mg/kg PO s.i.d.; 2 mg/kg SQ s.i.d. for up to three days. •• Cats: administer 30 minutes prior to surgery. N‐Methyl‐d‐Aspartate (NMDA) Receptor Antagonists/Gabapentin Administering drugs to preferentially bind to the NMDA receptor in the nucleus caudalis is an effective way to manage central sensitization associated with oral pain states. ■■ Amantadine: 3–5 mg/kg s.i.d. •• Pain‐modifying effect on the NMDA receptors in the spinal cord dorsal horn or medulla nucleus caudalis best used in conjunction with NSAIDs. •• May take days to have pain modifying effect. ■■ Ketamine: 2–20 μg/kg/min CRI. •• Subanesthetic doses of ketamine act on NMDA receptors to “unwind” pain. •• 60 mg ketamine (0.6 ml ketamine 10%) added to 0.5 liter of fluids infused at 5 ml/kg/h administers 10 μg/kg/min. Administer an IV loading dose of 0.25–0.5 mg/kg (0.01 ml per 4.5 kg) at induction. Alter fluid rate, or bolus IV fluid therapy utilizing a separate IV bag and pump during anesthesia. ■■ Gabapentin: 10 mg/kg PO every 8 hours dogs; 8 mg/kg every 6 hours cats. •• Single or double preprocedure dose of 15–30 mg/kg PO can be used as a fear‐free adjunct to help with transportation/exam or reduce postoperative need for opioids. •• GABA structure inhibits calcium channels in the dorsal horn/nucleus caudalis. •• Use to modify/minimize central sensitization and/or reduce the dose of opioids [8,13]. •• Not a stand‐alone pain management therapy.
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Other Tramadol: 4–10 mg/kg PO every 6 hours dogs; 2–4 mg/kg PO every 6–12 hours cats. •• The M1 metabolite (O‐desmethyltramadol) binds to the μ opioid receptor to provide analgesia. Cats produce O‐desmethyltramadol whereas dogs do not produce M1 significantly. M1 half‐life is 2 hours in dogs versus 7 hours in people [13]. •• Any benefit is through serotoninergic and noradrenergic effects for analgesia in dogs. The clinical signs of serotonin toxicity include increased neuromuscular activity, tachycardia, fever, tachypnea, and agitation. •• Never administer alone for pain management. •• Controlled substance with limited use; consider alternatives. ■■ Maropitant (Cerenia®, Zoetis): 1 mg/kg SQ or IV over 1–2 minutes, 2–2.5 mg/kg PO. •• Substance P inhibitor, best given SQ 1 hour prior or PO 2–3 hours prior to opioids. •• Refrigerate broached vials; administer refrigerated doses for decreased injection pain. •• Anti‐nausea drug, lower inhalant requirement, smoother anesthesia recovery, faster return to eating post procedure, and lower pain scores [8]. •• More than 90% of dog owners expressed nausea concern and would elect to pay for treatment. ■■ Anti‐nerve growth factor monoclonal antibody (anti‐NGF): study doses 0.2 mg/kg IV, 0.4–0.8 mg/kg SQ. •• One injection of frunevetmab appears to last four to six weeks [14]. •• Equal or more effective than NSAID‐treated controls. •• Research ongoing. ■■
Physical Medicine ■■
Acupuncture: electrostimulation of LI4, LU7, and other points. •• Safe, minimally invasive part of multimodal pain management [1]. •• Levels of β‐endorphin (μ‐opioid agonist) increase [15]. •• Electroacupuncture results in decreased inhalant anesthesia need [16]. •• Pain scores lower with acupuncture‐treated dental patients [17].
PROCEDURES ■■
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Local and regional nerve blocks placed preemptively reduce inhalant anesthetic needs of the patient, block transmission of the pain signal, and can extend the analgesia [9,10] into the home without owner action. Drug administration prior to an incision is more effective than the same drug after the incision [6] (see Figure 8.2).
Block Volumes (Table 8.1) Critical Point for Dental Blocks Opening the mouth excessively in cats (> 4 cm between the incisors) has been shown to compromise maxillary artery blood flow. Blindness and/or neurologic defects have been known to occur because there is no collateral brain and retina circulation. In a study on cats [18], 3 cm was a safe opening distance, while a syringe cap as an inflexible mouth prop caused problems in some, and spring‐loaded mouth gags were even more likely to cause problems. Spring‐loaded mouth gags should not be used. Maxillary Blocks Infraorbital block •• Palpate the infraorbital foramen dorsal to the third premolar. •• Hold the needle parallel to the palate and flat against the maxilla.
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•• Advance the needle into the canal no further than a site level with the medial canthus (Figure 8.3). •• As the infraorbital canal is approximately 4 mm long in cats, and minimal in brachycephalic dogs, advancing into the canal is not recommended due to close proximity of the eye (Figure 8.4). •• Aspirate before depositing the anesthetic within the canal. •• Gently remove and hold digital pressure on the site to avoid hematoma formation. •• Regional anesthesia will affect the oral tissue from the point of injection to the midline and rostral, including the hard palate. •• A “deep” block may block more area but still has difficulty desensitizing the caudal superior alveolar branch of the infraorbital nerve (Figure 8.5). •• For the maxillary fourth premolars and molars, the maxillary block is preferred.
■■ Figure 8.3 Infraorbital block: the distance from the rostral foramen opening to the medial canthus of the eye in a mesaticephalic skull is the distance to which a needle can be inserted.
■■ Figure 8.4 Infraorbital block: the distance from the rostral foramen opening to the medial canthus of the eye is greatly reduced in a brachycephalic skull.
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■■ Figure 8.5 Deep infraorbital block exits the infraorbital canal at the level of the pterygopalatine fossa, yet does not reliably desensitize the maxillary molars due to co‐innervation by the caudal superior alveolar branch of the infraorbital nerve.
■■ Figure 8.6 Red line shows needle placement for intraoral maxillary nerve block via caudal approach. ■■
Maxillary block •• Percutaneous approach ◦◦ Insert the needle through the skin just below the ventral rim of the zygomatic arch. ◦◦ For medium‐sized dogs, aim medially towards a point 0.5 cm caudal to a vertical line drawn from the medial canthus of the eye. •• Intraoral approach ◦◦ Caudally retract the lips. ◦◦ Immediately caudal to the last maxillary molar, insert the needle in a dorsal direction and redirect towards the nose (Figure 8.6). ◦◦ Dorsal insertion should not exceed 2–4 mm depending on patient size.
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◦◦ Pre‐bending the needle can aid in redirecting towards the nose. ◦◦ Accidental globe perforation is reported due to dorsal location. •• Alternative subzygomatic intraoral approach ◦◦ Hold the needle parallel to the palate approaching from a caudal direction (Figure 8.7). ◦◦ Puncture the mucosa just below the zygomatic arch, advancing as if aiming towards the opposite nostril as you enter the pterygopalatine fossa (Figure 8.8a). ◦◦ The goal is to affect the caudal superior alveolar branch supplying the maxillary molars as the needle is withdrawn. •• Aspirate before infiltrating the local anesthetic. •• Regional anesthesia will affect the entire maxillary quadrant. Mandibular Blocks ■■ Middle mental block •• Palpate the mental foramen ◦◦ Dogs: located ventral and slightly rostral to the mandibular second premolar (Figure 8.9). ◦◦ Cats: foramen is at or just caudal to the canine tooth apex.
■■ Figure 8.7 Maxillary block: alternative subzygomatic approach with the needle parallel to the palate, approaching below the zygomatic arch.
(a)
(b)
■■ Figure 8.8 Maxillary block: alternative subzygomatic approach. The syringe and needle will be directed towards the opposite nostril. Depositing block as the needle is withdrawn is more likely to affect the caudal superior alveolar nerve branch.
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■■ Figure 8.9 The middle mental foramen: ventral and slightly rostral to the mandibular second premolar in a dog. It may be possible to carefully enter the foramen in medium to large dogs.
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•• Insert the needle into the soft tissues just rostral to the foramen, advancing caudomedially. •• Sometimes it is only possible to enter the foramen in medium to large dogs. •• Aspirate before depositing the anesthetic within the canal. •• Gently remove and hold digital pressure on the site to avoid hematoma formation. •• Goal of regional anesthesia is to affect the area rostral to the injection. •• Desensitizes the lower lip and intermandibular region. •• Only the second, third, and fourth premolars are consistently desensitized. •• For a more reliable block, the caudal mandibular site is preferred. Inferior alveolar block (caudal mandibular) •• Extraoral approach ◦◦ Intraorally palpate the mandibular foramen located halfway between the angular process and the last molar dorsal to the ventral notch of the mandible (Figure 8.10). ◦◦ Insert the needle against the periosteum at the lingual cortex with the bevel facing the bone (Figure 8.11). ◦◦ Enter to a site one‐third the height of the mandibular body. ◦◦ Avoid needle puncture of your finger. ◦◦ If the local anesthetic drug is not placed next to bone or excessive volumes are used, desensitization of the lingual nerve and self‐trauma to the tongue could occur. •• Intraoral approach ◦◦ With the head in lateral recumbency, direct the needle towards the lingual aspect of the downside caudal mandible distal to the last molar. ◦◦ Advance the bevel to the area dorsal to the mid‐ventral mandibular notch. ◦◦ Has the potential to miss the foramen as the distance from the last molar to the foramen is often underestimated (Figure 8.12).
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■■ Figure 8.10 Inferior alveolar block: the distal foramen of the mandibular canal is located on a line halfway between the mandibular third molar and the angular process in a dog.
■■ Figure 8.11 Inferior alveolar block: extraoral approach. While identifying and palpating the distal foramen (dorsal to the mandibular notch) with a finger placed intraorally, advance the needle from an extraoral approach through the skin towards the location, staying close to the lingual periosteum of the mandible.
•• •• •• ••
◦◦ More reliable approach as it is more likely to deposit local anesthetic drug against periosteum (versus soft tissues) allowing the block agent to flow to the foramen/nerves. Avoid inadvertent deposition in adjacent soft tissues. This results in soft tissue absorption which is unlikely to reach the mandibular nerve. May also act on the lingual nerve (located in soft tissues) with subsequent tongue self‐trauma. Aspirate before infiltrating the local anesthetic. Gently remove needle and hold digital pressure on the site. Regional anesthesia will affect the entire mandibular quadrant.
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■■ Figure 8.12 Inferior alveolar block: intraoral approach. Direct the needle towards the lingual surface of the mandible distal to the last molar. Care must be taken to deposit the block against the periosteum and caudal at the foramen. Inset image illustrates it is easy to underestimate the distance, missing the foramen.
COMMENTS ■■
Pain management planning considering the whole patient ▪▪ Utilization of the pain pathway and drug classes becomes a guide to multimodal drug planning. A possible ideal multimodal anesthetic dental procedure plan includes: ◦◦ Maropitant 60 minutes prior to premedication [8]. ◦◦ Hydromorphone, dexmedetomidine premedication. ◦◦ Propofol or alfaxalone (no analgesic properties) induction over 90 seconds will minimize apnea and total dose needed to affect. ◦◦ Ketamine CRI can “unwind” the chronic/hidden oral pain found in 72–86% of dogs and cats [19,20]. ⋄⋄ +/– lidocaine ⋄⋄ +/– full μ opioid. ◦◦ Bupivacaine potentiated by buprenorphine [9,10] as local dental block: place prior to tissue manipulation (see Figure 8.2). ◦◦ NSAID utilized before, during, and/or three days after procedure. ▪▪ On many occasions, the ideal plan is modified to account for patient‐specific factors and risks. ◦◦ Keep emergency drug doses ready (www.csuvth.colostate.edu/emergencydrugcal- culator). ◦◦ Swap midazolam (0.1–0.2 mg/kg) for dexmedetomidine with opioid premedication. ◦◦ Electroacupuncture: beneficial non harmful multimodal therapy for all patient signalments. ◦◦ Grapiprant (Galliprant TM, Elanco) 2 mg/kg is a non‐cyclooxygenase‐inhibiting NSAID, and a possible replacement for a traditional NSAID, with unknown analgesic response for conditions beyond arthritis. ◦◦ Anti‐NGF monoclonal antibody may become a safe NSAID alternative with additional pain pathway actions.
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◦◦ Debilitated patients use less inhalant and have fewer adverse events with analgesic CRIs. ◦◦ Find CRI calculators at www.vasg.org ◦◦ All full μ opioids fulfill the requirement for loading doses, e.g. hydromorphone premedication is a loading dose for a fentanyl CRI. ◦◦ Loading doses may be administered via premedications instead of IV. Feline oral pain syndrome (FOPS) is an example of maladaptive pain that is characterized by an abnormal or excessive response to a non painful or minimally painful stimulus. •• A maladaptive or neuropathic pain syndrome analogous to trigeminal neuralgia in humans. •• Unilateral: ◦◦ Pawing at the mouth. ◦◦ Exaggerated licking and chewing movements. ◦◦ Mutilation of the tongue, lips, and oral mucosa. •• No neurologic signs, motor issues or sensory deficits. •• In one study [21], 88% of the 113 cats affected were Burmese, suggesting a hereditary tendency. •• Age of onset 0.5–20 years, average seven years. •• Mean time between episodes is two years. •• 16% appeared to be triggered by tooth eruption, but signs disappeared with full adult dentition. •• Treatments performed: ◦◦ Oral treatment aligned with coexisting dental disease. ◦◦ Phenobarbital: 88% of treated cases improved. ◦◦ Diazepam: 86% of treated cases improved. ◦◦ NSAIDs, antibiotics, or opioids were not effective. ◦◦ Multimodal therapy for neuropathic pain not reportedly performed on study patients. Possible Complications of local and regional blocks •• Intravascular injection of local anesthetic. •• Damage to nerve during injection. •• Lingual nerve blocked with inferior alveolar block technique: desensitization of tongue and potential self‐trauma. •• Persistent neuropathy.
Abbreviations ■■
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Anti‐NGF = anti‐nerve growth factor antibody b.i.d. = twice daily BLIS = bupivacaine liposomal injectable suspension BP = blood pressure CRI = constant rate infusion ETCO2 = end‐tidal CO2
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■■ ■■ ■■ ■■
FOPS = feline oral pain syndrome NMDA = N‐methyl‐d‐aspartate NSAID = nonsteroidal anti‐inflammatory drug OTM = oral transmucosal s.i.d. = once daily SpO2 = oxygen saturation EKG = electrocardiogram
References 1. Epstein M, Rodan I, Griffenhagen G, et al. 2015 AAHA/AAFP pain management guidelines for dogs and cats. J Am Anim Hosp Assoc 2015;51(2):67–84. 2. Mathews K, Kronen PW, Lascelles D, et al. Guidelines for recognition, assessment, and treatment of pain. J Small Anim Pract 2014;55(6):E10–E68. 3. Niemiec B, Gawor J, Nemec A, Clarke D, McLeod K, Tutt C, Gioso M, Steagall P, Chandler M, Morgenegg G and Jouppi R. World Small Animal Veterinary Association Global Dental Guidelines. J Small Anim Pract 2020; 61: E36-E161. doi.org/10.1111/jsap.13132..
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4. Summers J, O’Neill D, Church D, et al. Health‐related welfare prioritization of canine disorders using electronic health records in primary care practice in the UK. BMC Vet Res 2019;15(1):163. 5. Wiseman‐Orr ML, Nolan AM, Reid J, Scott EM. Development of a questionnaire to measure the effects of chronic pain on health‐related quality of life in dogs. Am J Vet Res 2004;65(8):1077–1084. 6. Beckman BW. Pathophysiology and management of surgical and chronic oral pain in dogs and cats. J Vet Dent 2006;23(1):50–60. 7. KuKanich B, Wiese AJ. Opioids. In: Grimm KA, Lamont LA, Tranquilli WJ, Greene SA, Robertson SA, eds. Veterinary Anesthesia and Analgesia: The Fifth Edition of Lumb and Jones. Ames, IA: John Wiley & Sons, 2015:207–226. 8. Grubb, T, Sager J, Gaynor JS, et al. 2020 AAHA anesthesia and monitoring guidelines for dogs and cats. J Am Anim Hosp Assoc 2020;56(2):59–82. 9. Grubb T, Lobprise H. Local and regional anesthesia in dogs and cats: overview of concepts and drugs (Part 1). Vet Med Sci 2020;6:209–217. 10. Grubb T, Lobprise H. Local and regional anesthesia in dogs and cats: descriptions of specific local and regional techniques (Part 2). Vet Med Sci 2020;6:218–234. 11. Tisotti T, Valverde A, Hopkins A, et al. Use of intravenous lidocaine to treat dexmedetomidine‐ induced bradycardia in sedated and isoflurane‐anesthetized dogs. Vet Anaesth Analg 2019;46(6):831. 12. Carlson AR, Nixon E, Jacob ME, Messeneger KM. Sterility and concentration of liposomal bupivacaine single‐use vial when used in a multiple‐dose manner. Vet Surg 2020;49(4):772–777. 13. Ruel H, Steagall P. Adjuvant analgesics in acute pain management. Vet Clin North Am Small Anim Pract 2019;49(6):1127–1141. 14. Enomoto M, Mantyh PW, Murrell J, et al. Anti‐nerve growth factor monoclonal antibodies for the control of pain in dogs and cats. Vet Rec 2019;184(1):23. 15. Groppetti D, Pecile AM, Sacerdote P, et al. Effectiveness of electroacupuncture analgesia compared with opioid administration in a dog model: a pilot study. Br J Anaesth 2011;107(4):612–618. 16. Robinson N. Interactive Medical Acupuncture Anatomy. New York: Teton NewMedia, 2016:65. 17. Grillo CM, Wada RS, da Luz Rosario de Sousa M. Acupuncture in the management of acute dental pain. J Acupunct Meridian Stud 2014;7(2):65–70. 18. Martin‐Flores M, Scrivani PV, Loew E, et al. Maximal and submaximal mouth opening with mouth gags in cats: implications for maxillary artery blood flow. Vet J 2014;200(1):60–64. 19. Verstraete FJ, Kass PH, Terpak CH. Diagnostic value of full‐mouth radiography in dogs. Am J Vet Res 1998;59(6):686–691. 20. Verstraete FJ, Kass PH, Terpak CH. Diagnostic value of full‐mouth radiography in cats. Am J Vet Res 1998;59(6):692–695. 21. Rusbridge C, Heath S, Gunn‐Moore DA, et al. Feline orofacial pain syndrome (FOPS): a retrospective study of 113 cases. J Feline Med Surg 2010;12(6):498–508.
Internet Resources www.csuvth.colostate.edu/emergencydrugcalculator (accessed 25 January 2021) www.vasg.org (accessed 25 January 2021) Author: Jennifer R. Mathis, DVM, CVPP Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
9
Equipment, Instruments and Maintenance DEFINITION/OVERVIEW ■■
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To provide appropriate dental services and treatment, it is essential to have the correct equipment and instrumentation. Regular inspection and care of equipment and instruments will keep them efficient and functional. Dull instruments or equipment that is not well maintained will not only have a shorter span of use, but can make dental practice frustrating. The equipment and instruments mentioned in this chapter represent just a small fraction of all the products available and some are the authors’ primary preferences. No special recommendations or omissions are intended.
EQUIPMENT Personal Protection Equipment ■■
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Exam gloves: for most examinations and procedures. •• Sterile surgical gloves for advanced surgical procedures. Mask or face shield. Eye protection (if face shield not used). Surgical loupes +/– light. •• Essential for visualization. •• Allow for better posture during procedures. Floor mats for standing during long procedures. Ergonomic chairs: support proper posture. Radiation exposure monitoring and protection. •• Dosimeter badge. •• Lead tabletop radiation blocker (Figure 9.1). •• Lead vest.
Standard Equipment for Oral Assessment and Cleaning (Figure 9.2) ■■
Ultrasonic scaler •• Multiple styles of ultrasonic scalers: all should be used with care on the teeth and with proper training. ◦◦ As these produce heat when used, adequate water spray on the tip is essential. ◦◦ Do not use on the surface of the crown for longer than 15 seconds at a time (some recommend 5–10 seconds). ◦◦ None (few exceptions) should be used subgingivally.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 97
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■■ Figure 9.1 Tabletop lead shield for radiation protection that bends in the middle.
■■ Figure 9.2 Standard equipment for oral assessment and cleaning: (left to right) dental mirror, periodontal probe/ explorer, hand curette, hand scaler, calculus forceps, pen light for transillumination, polishing angle, and cup of polishing paste.
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•• Magnetostrictive ◦◦ Stack of nickel strips as an insert cause the tip to vibrate in an elliptical pattern. ◦◦ 25 or 30 kHz. •• Piezoelectric ◦◦ Stack of ceramic disks inside the scaler handpiece vibrate the handpiece’s tip. ◦◦ Linear motion produces a more sensitive technique: scaler needs to stay parallel to tooth surface. Do not use the tip. ◦◦ Generates less heat and is gentler than magnetostrictive scalers. ◦◦ 32–35 kHz. Low‐speed polisher •• Micro motor pack or low‐speed handpiece on dental unit (less than 3000 rpm). •• A replaceable polishing angle can be attached to a low‐speed handpiece directly, or a replaceable polishing cup can be attached to a low‐speed contra‐angle. Polishing (prophy) paste •• Fine or medium grit polishing paste only. •• Flour pumice without fluoride if bonding agents or restoratives are to be placed.
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Periodontal probe •• Marked in millimeters: various markings and names. ◦◦ Some with indentations at 1, 2, 3, 5, 7, 8, 9 and 10 mm. ◦◦ Some marked with 3‐mm bands of black and silver. •• Often on a double‐ended instrument with a periodontal explorer. Periodontal explorer (shepherd’s hook) •• Sharp tip used to locate soft areas of enamel, open canals, and other enamel defects. •• Very useful when searching for feline restorative lesions. •• Commonly found at the other end of a probe. Hand scalers •• Sharp tip, often triangular in cross‐section, with a sharp “back.” •• Used on the surface of the crown only (not subgingivally), for removing calculus on the surface of the crown and in the developmental grooves of the teeth. ◦◦ Jacquette scaler. Hand curettes •• Rounded tip, and half‐moon shape in cross‐section, with a rounded “back.” •• Double‐ended; working heads mirror images of each other. •• Hand instrument used subgingivally for the removal of debris and calculus. With face “closed,” only one edge will be used to contact the surface of the tooth (see Chapter 5). •• The blunted tip will not cause damage to the gingiva, unlike hand scalers that have a sharp tip. ◦◦ Gracey, universal. Dental mirror: necessary to visualize hard‐to‐see places such as the caudal area or the maxillary molars. Calculus forceps: can help in the careful removal of bulk calculus from the crown. •• Time for calculus removal by the ultrasonic scalers can be decreased. •• Care should be taken to avoid damaging the tooth. Transilluminator •• Bright light such as a pen light or Finhoff transilluminator on an otoscope. •• When the light is held behind a tooth (allowing the light to shine through it), the pulp is evaluated for vitality (pink center vs. dark; compare to other teeth).
Standard Equipment for Oral Surgery ■■
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Oral surgery sets can be organized and color‐coded to provide a full set of instruments typically needed for extractions and soft tissue management (Figure 9.3). •• Multiple sets with slight variations in instrument sizes can be organized for optimal workflow, with rotation of sets for cleaning, sharpening, and sterilization. •• Operator preference for specific instruments can also be organized. High‐speed handpiece (Figure 9.4) •• Provides up to 400 000 rpm to be used with the appropriate burs. ◦◦ For sectioning teeth before extraction and initial removal of alveolar bone (Figure 9.5a): ⋄⋄ Crosscut fissure burs (699, 699L, 700, 700L, 701). ⋄⋄ Round and pear burs. ◦◦ For special use (Figure 9.5b): ⋄⋄ Odontoplasty (white stone bur). ⋄⋄ Alveoloplasty (diamond burs). ⋄⋄ Gingivoplasty (12‐fluted finishing bur). Dental elevators, luxators and root‐tip picks •• Elevators are blade‐tipped instruments used to lever the tooth out of its socket; they are durable and strong with thick tips and are designed to withstand the force needed for leverage (Figure 9.6).
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■■ Figure 9.3 Standard equipment for oral surgery: (bottom, left to right) LaGrange scissors, iris scissors for suture, needle drivers, small‐breed extraction forceps, root‐tip pick, two small straight elevators (1.3S‐XS and 1.8S‐XS), and six sizes of winged elevators (1–6 mm); (top left) 4‐0 and 5‐0 monofilament sutures packs and lip retractor; (top right) two double‐ended periosteal elevators and two thumb forceps.
■■ Figure 9.4 High‐speed handpiece.
•• Winged elevators #1–6: curved edges of blade matched to fit the size/diameter of root. •• Luxators resemble elevators in shape but their tips are more delicate than elevators and can be easily inserted into the narrow apical space. The tips are thin and sharp and can break if force is applied during extraction. •• Flat straight and curved elevators can be used based on personal preference. •• Smaller delicate elevators can be used for cat teeth as well as root tips, such as Cislak 1.3S and 1.8S (Figure 9.7). •• Root‐tip picks: used for excavating small broken roots (RT‐1) (Figure 9.8).
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(a)
(b)
■■ Figure 9.5 (a) Burs for sectioning in a high‐speed handpiece: (left to right) two crosscut fissure burs, one pear and, one round bur. (b) Burs for special use in a high‐speed handpiece: (left to right) 12‐fluted gingivectomy bur, two diamond burs, and white stone bur.
■■ Figure 9.6 Dental elevators: (top) luxator (flat elevator); (bottom) winged elevator.
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■■ Figure 9.7 Small elevator (1.3S) used for feline teeth or root tips.
■■ Figure 9.8 Root‐tip pick (RT‐1).
■■ Figure 9.9 Dental extraction forceps: (left to right) curved tips, small breed, and molar forceps.
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Extraction forceps: for the removal of the tooth after elevating (loosening the tooth in the socket) with minimal force (Figure 9.9). Match the proper size of forceps to the size of the tooth. Do not use a large dog canine forceps while removing cat’s teeth. Periosteal elevators: used for making gingival flaps as well as debriding the socket of extractions before closure (Molt 2/4, EX‐9, EX20‐21) (Figure 9.10). Serrated periosteal elevators are useful for debridement.
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■■ Figure 9.10 Periosteal elevator: double‐ended with Molt #4 and Molt #2.
■■ Figure 9.11 LaGrange tissue scissors.
■■ Figure 9.12 Tissue forceps: rat‐tooth and Adson (Adson‐Brown). ■■
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Scissors •• Sharp scissors for cutting and dissecting tissues (LaGrange, iris, Metzenbaum) (Figure 9.11). •• Suture scissors. Tissue forceps (Figure 9.12): small delicate forceps for handling tissues (rat‐tooth or Adson). Needle drivers (Figure 9.13) •• Needed to grasp needle and suture to close surgical sites. •• Great variety based on personal preference; often smaller instruments due to limited space in the oral cavity. Suture (Figure 9.14) •• Great variety based on purpose and personal preference: ◦◦ Braided material softer, but can wick bacteria.
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■■ Figure 9.13 Castroviejo needle drivers.
■■ Figure 9.14 Monofilament suture material.
■■ ■■
◦◦ Monofilament: good handling but larger sizes can be stiff. ◦◦ Chromic catgut: may cause “drag” through the tissues. •• Authors’ preference: 4/0 or 5/0 Monocryl with reverse cutting needle for dogs, and a tapered needle for cats. Lip retractors (Figure 9.15): instrument used to hold back lips for better viewing field. Piezotome (Figure 9.16) •• Directed power cutting equipment: ◦◦ Reduce strain on operator compared to using elevators for extractions. Up and down motion in periodontal ligament space. ◦◦ Soft tissue is preserved with minimal bone loss as compared to using burs on a high‐speed handpiece for osseous resection. ◦◦ Deep cuts with consistent irrigation flow. ◦◦ Decrease in pain and swelling.
Radiology ■■
Generator •• Dental unit with wall mount or wheeled stand. •• Hand‐held units are available.
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■■ Figure 9.15 Lip retractor.
■■ Figure 9.16 Cube piezotome. ■■
Image capture (see Chapter 3) •• Traditional dental films with developing/fixing fluids. •• Digital radiography: ◦◦ “Direct” radiography (DR): digital sensor with immediate image. ◦◦ “Computed” radiography (CR): phosphor plates (photostimulated luminescence screens processed through a reader. •• Advanced imaging: computed tomography.
MAINTENANCE Sharpening One of the biggest headaches of veterinary dentistry is trying to work with dull instruments. Basic care and maintenance of all instruments includes regular sharpening of hand instruments. Elevators are used by getting into the space between the tooth and alveolar bone and fatiguing the periodontal ligament, and dull instruments make this difficult.
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Sharpening implements •• Sharpening stone ◦◦ Arkansas stone: ⋄⋄ Flat stones are probably better suited for hand scalers and curettes. ⋄⋄ Wedge, with rounded edges, for winged elevators. ⋄⋄ Water or oil to prevent excess friction. ◦◦ Honing machine: rapid action and can damage instruments or remove too much metal if care is not taken. Sharpening technique •• Dental elevators ◦◦ After applying the water or oil, place the face of the elevator on the curved edge that the face fits best (Figure 9.17). ◦◦ Draw the elevator towards you, holding it at a 30–45° angle, 10–15 times with firm pressure. ◦◦ After you have done this, it is recommended that you do the back side of the elevator. Using the same angle as before, draw it towards you in a twisting motion to take out any folds that the metal may have experienced during the sharpening process. •• Periosteal elevators (Molt) ◦◦ These are sharpened in a similar manner by placing the face of the molt down flat onto the stone surface, drawing towards you 10–15 times and making sure you work all edges of the molt (Figure 9.18). •• Hand scalers ◦◦ Sharpen both sides of each working face by pushing the instrument along the stone while ensuring the instrument sits with the lateral cutting edge down facing the stone (usually falls naturally to that side when gently held against a flat surface). ◦◦ Make 10–15 passes across the stone for each edge of the triangular working head. •• Hand curettes (get a dental hygienist to teach you or watch YouTube) ◦◦ Only one edge of each working head is using for scaling/curettage. ◦◦ Moving stone technique: ⋄⋄ Apply stone to lateral surface to form a 110° angle with the face.
■■ Figure 9.17 Sharpening the inside curve of a winged elevator on the rounded edge of an Arkansas stone that correlates to the tip size.
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■■ Figure 9.18 Sharpening the edge of a periosteal elevator.
■■ Figure 9.19 Placing the cutting edge of a curette at a 90° angle to the stone initially.
■■ Figure 9.20 Adjusting the head 20° to facilitate sharpening the edge at the correct angulation.
⋄⋄ Position the stone to contact the heel of the blade and work towards the tip. ⋄⋄ Move the stone up and down with short strokes. ◦◦ Moving instrument technique: ⋄⋄ Place curette cutting edge on stone at a 90° angle at first (Figure 9.19). ⋄⋄ Adjust curette edge on stone, forming a 110° angle (Figure 9.20).
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⋄⋄ Work the blade from the heel of the face to the toe, maintaining the angle as you pull the curette across the stone. ◦◦ Make sure the toe of the curette remains rounded. Rinse stone of any sludge or metal buildup that may have developed before moving on to the next instrument or putting away for storage. Periodically use emery paper or board to scrub the surface of the sharpening stone to remove any metal buildup that may have occurred.
High‐speed Handpiece Maintenance ■■
Lubrication •• High‐speed and low‐speed handpieces need to be oiled daily due to the constant friction and wear on the turbines (Figure 9.21). •• If you fail to do so, turbines tend to wear out more quickly and will need to be replaced frequently. •• Make sure that oil is only placed in the air inlet of the handpiece, i.e. the smaller of the two large holes on the underside of the handpiece when removed from the connector (Figure 9.22).
Dental Unit and Air Compressor Maintenance (general) ■■
■■ ■■ ■■ ■■ ■■
Most units these days have the “all‐in‐one” unit with compressors built in. Modern compressors are usually oil‐free. However, if the compressor you have does take oil, make sure that the oil level is checked regularly and that it is changed according to the manufacturer’s recommendations. Air tanks need to be drained regularly; most dental compressors require this daily. Check air filters of compressor and change as the manufacturer recommends. Clean unit daily so as to prevent any corrosion or oil buildup. Empty distilled water bottles regularly to prevent biofilm buildup. Use in‐line dental unit cleaners regularly to stop biofilm buildup within the unit itself.
■■ Figure 9.21 Daily lubrication is needed for high‐speed handpieces.
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■■ Figure 9.22 Place the oil in the air inlet only (the smaller of the two large holes in the base).
■■ Figure 9.23 Dental elevators: new one on left (though edge is not sharp); old one on right, where use and sharpening have removed enough metal that the edge is now thick and needs replacement.
Replacing Instruments ■■
■■
Replacing old, worn‐out, or damaged instruments is key in oral surgery. •• Even with proper upkeep, elevators, scissors, and hand instruments all have a life expectancy. •• Do not be afraid to change that lucky elevator that worked on getting out those upper fourth premolars for all those years. Elevators, as they get used and sharpened time and time again, lose metal and become thicker as they do. Once an elevator has lost around 2 mm of metal, the narrow tip of the instrument will be gone and the thicker metal of the mid‐portion of the instrument will be exposed (Figure 9.23).
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■■ Figure 9.24 Hand curettes: new one on right; old one on left, where use and sharpening have weakened the metal. ■■
As with elevators, hand instruments will become fragile and thin over time and are more prone to breaking once they have been sharpened many times (Figure 9.24).
Author: Shannon VanTrease Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Section
III
Oral/Dental Diseases: Developmental Oral/Dental Problems
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Chapter
10
Persistent (Retained) Deciduous Teeth DEFINITION/OVERVIEW ■■
A persistent (retained) deciduous tooth (DT/P) is one that is still present when the permanent tooth begins to erupt or has fully erupted.
ETIOLOGY/PATHOPHYSIOLOGY ■■
Dogs/cats •• Numerous factors influence the exfoliation of deciduous teeth: ◦◦ Lack of permanent successor. ◦◦ Ankylosis of deciduous root to alveolus. ◦◦ Failure of permanent crown to contact deciduous root during eruption (Figure 10.1). •• Incidence/prevalence; unknown. •• Cause is unknown but is suspected to have a familial/genetic basis.
■■ Figure 10.1 Radiograph of developing permanent fourth premolar beneath the deciduous tooth in a dog. When the permanent tooth erupts, the deciduous tooth should be exfoliated.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 113
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SIGNALMENT/HISTORY ■■
■■
■■
■■
Species •• Canine more likely than feline. Breed predilections •• Small‐breed dogs: Maltese, Poodle, Yorkshire terriers, Pomeranian, etc. Mean age and range •• During permanent tooth eruption phase. •• Begins at three months for incisors and up to five to seven months for canine teeth and molars. •• May not be detected or diagnosed until later in life. Predominant sex: no correlation.
CLINICAL FEATURES ■■
General comments •• Persistent deciduous teeth can cause the permanent teeth to erupt in abnormal positions resulting in a malocclusion. Early recognition and intervention is essential (see Chapter 19). ◦◦ Maxillary canine teeth erupt mesial (rostral) to the persistent deciduous canine teeth. This can result in a diastema (space) between the maxillary canine and third incisor that is too narrow to accommodate the crown of the mandibular canine. This maxillary canine position is referred to as mesioversion (Figure 10.2). ◦◦ Mandibular canine teeth erupt lingual to the persistent deciduous teeth. This can result in a narrow space between the lower canines (base‐narrow) resulting in impingement on the palate. The mandibular canine position is referred to as linguoversion (Figure 10.3). ◦◦ All incisors erupt lingual to the persistent deciduous incisors. This can result in a rostral crossbite.
■■ Figure 10.2 Multiple persistent deciduous teeth, including the maxillary canine, with the permanent tooth erupting mesial to the deciduous tooth.
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■■ Figure 10.3 Permanent mandibular incisors and canines erupting lingual to the persistent deciduous teeth. ■■
Physical exam findings •• Presence of deciduous tooth with permanent tooth erupting or fully erupted. •• Abnormal position of permanent tooth due to persistence of deciduous tooth (see General comments above). •• Oral malodor from accumulation of debris and plaque due to crowding of the permanent and deciduous teeth. •• Local gingivitis and periodontal disease due to crowding. •• Oronasal fistula from base‐narrow mandibular canine teeth. •• Deciduous tooth is usually smaller than the permanent tooth. •• Deciduous tooth might not have an underlying permanent tooth and will often remain intact and vital.
DIFFERENTIAL DIAGNOSIS ■■ ■■
Supernumerary teeth Gemination of the crown
DIAGNOSTICS ■■
■■
■■
Complete oral examination •• Charting ◦◦ Indicate presence of persistent (retained) deciduous teeth. ◦◦ Indicate malpositioned teeth, missing teeth, soft tissue trauma, and other oral abnormalities. Imaging •• Intraoral radiographs ◦◦ Distinguish between permanent tooth and deciduous tooth. ◦◦ Provide evidence or extent of root resorption of deciduous tooth. ◦◦ Identify dental abnormalities prior to extraction. ⋄⋄ Persistent deciduous tooth with no permanent successor. ⋄⋄ Retained root with crown missing. ⋄⋄ Unerupted permanent tooth (see “missing teeth”; Chapters 14 and 17). Appropriate preoperative diagnostics when indicated prior to procedure.
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THERAPEUTICS Drugs ■■ ■■
Topical oral antimicrobial rinse prior to extraction Pain management prior to and post extraction
Procedures ■■
■■
Extraction of deciduous tooth •• Pain management: ◦◦ Local/regional. ◦◦ Systemic. •• General anesthesia with endotracheal tube in place. •• Intraoral radiographs. •• Elevation of deciduous tooth. ◦◦ Careful, gentle elevation is critical. Excessive force can damage the developing permanent tooth (and other underlying structures). ◦◦ Fractured or retained root may need to be removed with a gingival flap. ⋄⋄ If a permanent tooth has erupted in an abnormal position, full root extraction of the deciduous tooth is essential. ⋄⋄ In some cases, the root may have already undergone resorption and need not be extracted. Patient monitoring and home care •• Restrict activity for the rest of the day. •• Soft diet for three days (canned food or moistened dry kibble). •• Analgesia (nonsteroidal anti‐inflammatory drug, NSAID) for 24–36 hours postoperatively. •• No chew toys for three days. •• Oral rinse or gel (chlorhexidine) for three to five days if indicated. •• Continue daily tooth brushing after 24 hours.
COMMENTS ■■ ■■
■■
Client education: may be prevalent in certain breeds/lines; avoid similar breeding. Monitoring •• Start evaluating the teeth and occlusion during the first puppy/kitten visit. •• Inform owners you will be evaluating for proper eruption of permanent teeth as well as exfoliation of deciduous teeth. Possible complications •• Malocclusion that results after full eruption of permanent teeth may require treatment. ◦◦ Mesioversion of one or both maxillary canine teeth. ◦◦ Linguoversion of one or both mandibular canine teeth.
Expected Course and Prognosis ■■
Once extracted, there should be no further problems, unless resulting permanent malocclusion needs further attention.
CHAPTER 10 PERSISTENT (RETAINED) DECIDUOUS TEETH
See also the following chapters: Chapter 13 ■■ Chapter 14 ■■ Chapter 17 ■■ Chapter 19 ■■ Appendix C (Generations of Teeth in Diphyodont Species) ■■
Abbreviations ■■ ■■
DT/P = deciduous tooth persistent NSAID = nonsteroidal anti‐inflammatory drug
Author: Randi Brannan, DVM, FAVD, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
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Chapter
11 Craniomandibular Osteopathy
DEFINITION/OVERVIEW ■■ ■■
■■ ■■
A self‐limiting, developmental, orthopedic disease of young animals. Nonneoplastic proliferation of parietal bone, occipital bone, tympanic bullae, mandibular rami or bones of the temporomandibular joint (TMJ); occasionally long bones. Bilateral symmetric involvement most common. Also known as “lion jaw,” “Westie jaw,” “Scottie jaw.”
ETIOLOGY/PATHOPHYSIOLOGY ■■
■■ ■■
West Highland White, Cairn and Scottish Terriers: monogenic mutation in chromosome 5, autosomal dominant and incomplete penetrance; impaired glucose homeostasis in bone leading to hyperostosis. Patterns of inheritance unknown in other breeds. Young terrier with periosteal long bone disease: monitor for disease.
SIGNALMENT/HISTORY ■■ ■■
■■ ■■ ■■ ■■ ■■ ■■
Scottish, Cairn, and West Highland white terrier breeds: most common. Labrador retrievers, Great Danes, Boston terriers, Doberman pinschers, Irish setters, English bulldogs, and boxers: may be affected. Usually growing puppies three to eight months of age. No gender predilection. Usually relate to pain around the mouth and difficulty eating. Angular processes of the mandible affected: jaw movement progressively restricted. Difficulty in prehension, mastication, and swallowing: may lead to starvation. Lameness or limb swelling: may precede cranial involvement.
CLINICAL FEATURES ■■ ■■ ■■ ■■ ■■ ■■
Pain on opening the mouth or palpating the mouth Intermittent fever Excessive salivation Bilateral, firm, painful mandibular swellings (Figure 11.1) Restricted jaw movement Temporal and masseter muscle atrophy
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 118
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■■ Figure 11.1 Bilateral firm painful mandibular swellings. Source: courtesy of Heidi B. Lobprise.
DIFFERENTIAL DIAGNOSIS ■■
■■
■■
■■
Osteomyelitis: bones not symmetrically affected; generally not as extensive; lysis; lack of breed predilection; history of penetrating wound. Traumatic periostitis: bones not symmetrically affected; generally not as extensive; history of trauma. Neoplasia: mature patient; not symmetrically affected; more lytic bone reaction; metastatic disease. Calvarial hyperostosis: young patient. •• Firm swelling of the cranium in the region of the frontal sinus. •• Appears histologically as new bone formation with thick trabeculae of immature woven and mature lamellar bone separated by cementing lines. •• Has been combined with CMO into umbrella term “idiopathic canine juvenile cranial hyperostosis.”
DIAGNOSTICS ■■
■■ ■■
■■
Skull radiography reveals uneven, bead‐like, osseous proliferation of the mandible or tympanic bullae (bilateral); extensive periosteal new bone formation (exostoses) affecting one or more bones around the TMJ; may show fusion of the tympanic bullae and angular process of the mandible (Figure 11.2). Computed tomography (CT): may help evaluate osseous involvement of the TMJ. Bone biopsy •• Biopsy shows interconnected trabeculae of woven bone, proliferative endosteal new bone, and abundant osteoclasts on the surface. •• Marrow spaces filled with loose connective tissue. •• Few foci of inflammatory cells. Cultures to rule out infectious agents.
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■■ Figure 11.2 Extensive periosteal new bone formation (exostoses) affecting both mandibles. Source: courtesy of Heidi B. Lobprise.
THERAPEUTICS ■■ ■■
Most cases are self‐limiting: provide supportive care Nutritional support
Drugs ■■ ■■ ■■
Analgesics and anti‐inflammatory drugs: palliative use warranted. Nonsteroidal anti‐inflammatory drugs (NSAIDs): inhibit cyclooxygenase enzymes. Corticosteroids in some cases.
Procedures ■■ ■■
Surgical excision of exostoses: results in regrowth within weeks. Surgical placement of a pharyngostomy, esophagostomy, or gastrostomy tube: considered to help maintain nutritional balance.
COMMENTS ■■
■■ ■■ ■■
Frequent reexaminations mandatory to ensure adequate nutritional balance and pain control. Do not repeat dam–sire breedings that resulted in affected offspring. Discourage breeding of affected animals. Synonyms: lion jaw, Scottie jaw, Westie jaw.
Expected Course and Prognosis ■■
Pain and discomfort may diminish at skeletal maturity (10–12 months of age); the exostoses may regress.
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Prognosis: depends on involvement of bones surrounding the TMJ. •• Boney changes resulting in inability to open the mouth has a guarded prognosis. Elective euthanasia may be necessary.
Abbreviations ■■ ■■ ■■ ■■
CMO = craniomandibular osteopathy CT = computed tomography NSAIDs = nonsteroidal anti‐inflammatory drugs TMJ = temporomandibular joint
Suggested Reading Franch J, Sesari JR, Font J. Craniomandibular osteopathy in two Pyrenean mountain dogs. Vet Record 1998;142(17):455–459. Huchkowsky SL. Craniomandibular osteopathy in a bullmastiff. Can Vet J 2002;43(11):883–885. LaFond E, Breur GJ, Austin CC. Breed susceptibility for developmental orthopedic diseases in dogs. J Am Anim Hosp Assoc 2002;38(5):467–477. McConnell JF, Hayes A, Platt SR, Smith KC. Calvarial hyperostosis syndrome in two bullmastiffs. Vet Radiol Ultrasound 2006;47(1):72–77. Padgett GA, Mostosky UV. The mode of inheritance of craniomandibular osteopathy in West Highland White terrier dogs. Am J Med Genet 1986;25(1):9–11. Pastor KF, Boulay JP, Schelling SH, Carpenter JL. Idiopathic hyperostosis of the calvaria in five young bullmastiffs. J Am Anim Hosp Assoc 2000;36(5):439–445. Taylor SM, Remedios A, Myers S. Craniomandibular osteopathy in a Shetland sheepdog. Can Vet J 1995;36(7):437–439. Watson ADJ, Adams WM, Thomas CB. Craniomandibular osteopathy in dogs. Compend Contin Educ Pract Vet 1995;17:911–921.
This topic was edited for oral/dental content from previous publication in Five Minute Veterinary Consult, 5th edition. Authors: Steven M. Cogar, DVM and Spencer A. Johnston, VMD, DACVS Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
12 Enamel Hypocalcification
DEFINITION/OVERVIEW ■■
■■
■■ ■■
■■
■■
Apparent defect in enamel surfaces, often pitted and discolored; focal or generalized defects due to disruption of normal enamel formation (Figure 12.1). Some have extensive structural damage, even root involvement. Sometimes incorrectly referred to as enamel hypoplasia, which is the inadequate deposition of normal enamel matrix, affecting one or several teeth. The crowns can have areas of normal enamel next to hypoplastic or missing enamel. Enamel hypoplasia is less common than hypocalcification. Most cases of enamel hypoplasia are primarily esthetic; the dentin is rarely exposed with hypoplasia. •• Enamel hypocalcification, otherwise known as hypomineralization, refers to the inadequate mineralization of enamel matrix, affecting several or all teeth. The crowns of affected teeth are covered by poorly formed, rough enamel that may be easily worn or flaked away and have light brown discoloration, exposing the dentin. Teeth may be more sensitive with exposed dentin, and occasionally fractures of severely compromised teeth occur; usually they remain fully functional. Systemic influences during enamel formation (e.g. distemper, fever) over an extended time may cause generalized changes. Local or focal influences (e.g. trauma, deciduous tooth fracture or extraction) over a short time period may cause specific patterns or bands (Figure 12.2).
■■ Figure 12.1 Generalized enamel hypocalcification defects including the incisors.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 122
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■■ Figure 12.2 Local or focal influences (e.g. trauma, even from deciduous tooth extraction) over a short time period likely caused these focal areas of change.
ETIOLOGY/PATHOPHYSIOLOGY ■■
Dogs/cats •• Insult during enamel formation. •• Canine distemper virus, fever, trauma (e.g. accidents, fractured deciduous tooth, excessive force during deciduous tooth extraction).
SIGNALMENT/HISTORY ■■ ■■
Dogs (more common) and cats (less common). Often apparent at time of tooth eruption (after six months of age) or shortly thereafter (with signs of wear).
CLINICAL FEATURES ■■
■■
■■ ■■
Irregular, pitted, or flaky enamel surface with discoloration of diseased enamel and potential exposure and staining of underlying dentin (light brown). Early or rapid accumulation of plaque and calculus on roughened tooth surface; possible gingivitis and/or accelerated periodontal disease. Teeth may fracture more easily. Animals may show cold sensitivity (avoiding outdoor water or refrigerated foods).
DIFFERENTIAL DIAGNOSIS ■■ ■■ ■■
■■
Enamel staining: discolored but smooth surface (tetracycline) (see Chapter 24). Carious lesions: cavities with decay (see Chapter 25). Amelogenesis imperfecta: genetic and/or developmental formation and maturation abnormalities other than hypomineralization. Tooth resorption: similar to those found in cats; also found in dogs.
DIAGNOSTICS ■■ ■■
Complete oral examination. Complete blood count, biochemistry, urinalysis. •• Appropriate preoperative diagnostics prior to procedure.
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■■ Figure 12.3 Generalized enamel hypocalcification of mandibular teeth.
■■ Figure 12.4 Radiograph of teeth shown in Figure 12.3 showing extensive root dysplasia of affected teeth. ■■
Imaging •• Intraoral radiographs are necessary to determine the structure and viability of roots. •• Cases reported of abnormal root formation, no root formation, or separated crown and root (Figures 12.3 and 12.4).
THERAPEUTICS Procedures ■■ ■■ ■■
■■
Treatment depends on extent of lesions and equipment and materials available. Goal is to provide the smoothest surface possible. Enamel hypoplasia typically does not require treatment as the enamel is normal, just decreased in thickness. Enamel hypocalcification lesions typically benefit from treatment. Optimal treatment •• Gently remove diseased enamel (enamel scrub) with white stone burs or finishing disks on high‐speed handpiece (adequate water coolant).
■■
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•• Take care not to damage the tooth: excess enamel/dentin removal; hyperthermic damage to pulp. •• Focal defects may be amenable to composite restoration, but many restorative materials (bonding agents, composites) require use of light‐curing units and appropriate skill levels. •• Bonding agent recommended to seal exposed dentinal tubules and protect surface. •• Extraction is recommended if the root is significantly malformed; extraction or root canal if the tooth is radiographically nonvital. Alternate treatment •• The soft diseased enamel can sometimes be removed with ultrasonic scalers or hand instruments, but avoid excessive removal and hyperthermia. •• Fluoride treatment can be used to decrease sensitivity and enhance enamel strength.
COMMENTS ■■
■■
■■
Inform the owner that further degeneration of remaining enamel may occur, necessitating additional therapy in the future, or that affected teeth may become nonvital over time, requiring root canal therapy or extraction. Regular professional dental cleaning and a routine home care program (brushing); may include weekly application of stannous fluoride at home (minimize ingestion because of toxicity). Avoid chewing on hard objects.
Expected Course and Prognosis ■■
Good to fair to guarded (for the tooth), depending on extent of lesion and root involvement.
See also the following chapters: Chapter 24 ■■ Chapter 25 ■■ Chapter 26 ■■ Appendix C (Abnormalities of Enamel Formation) ■■
Abbreviation ■■
EH = enamel hypoplasia/hypocalcification
Suggested Reading Bittegeko SB, Arnbjerg J, Nkya R, Tevik A. Multiple dental developmental abnormalities following canine distemper infection. J Am Anim Hosp Assoc 1995;31(1):42–45. Lobprise HB, Dodd JR, eds. Wiggs’ Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019.
Author: Kristin Bannon, DVM, FAVD, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
13
Eruption Disruption/Abnormalities
DEFINITION/OVERVIEW ■■
■■ ■■
■■
■■
Delay, disruption or lack of normal eruption sequence of teeth at anticipated or appropriate times. Unerupted tooth (T/U): tooth that has not perforated the oral mucosa. Embedded tooth (T/E): unerupted tooth covered in bone whose eruption is compromised by lack of eruptive force. Impacted tooth (T/I): unerupted or partially erupted tooth whose eruption is prevented by contact with a physical barrier. Operculum: tough fibrous gingival covering that may persist over the crown of a tooth, even if eruption movement is completed. It may appear as an unerupted tooth (Figure 13.1).
ETIOLOGY/PATHOPHYSIOLOGY ■■ ■■ ■■
Imbalances of endocrine system: retarded tooth eruption. Mechanical barriers: closed diastema, malocclusion. Persistence/retention of deciduous teeth.
■■ Figure 13.1 Operculum covering mandibular incisors and canines.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 126
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Trauma to developing tooth that would impair complete eruption or intrude the tooth. Familial/breed tendencies.
SIGNALMENT/HISTORY ■■ ■■
■■
Occurring in dogs and cats. Monitor eruption sequence during appropriate period of development. •• Deciduous teeth. •• Permanent teeth: four to six months. Delayed eruption: Tibetan terriers, Portuguese water spaniels, Chinese crested.
CLINICAL FEATURES ■■
■■ ■■ ■■
Unerupted: absence of erupted crown; if not truly missing, will be present radiographically under the gingival surface. •• Mandibular first premolars are a common tooth unerupted in bracycephalic breeds (Figures 13.2 and 13.3). Embedded. Submerged. Operculum: crown may be nearly erupted to full height but is covered, partially or completely, with thick fibrous operculum.
■■ Figure 13.2 Apparently missing right mandibular first premolar (406).
■■ Figure 13.3 Radiograph of site in Figure 13.2 shows unerupted first premolar with moderate bone loss around the crown.
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DIFFERENTIAL DIAGNOSIS ■■ ■■ ■■ ■■ ■■
Hypodontia (HYP): missing teeth (several). Anodontia (ANO): missing teeth (all). Fractured crown (radiograph to confirm presence of root). Epulis, neoplasia or gingival hyperplasia (to distinguish from operculum). Traumatic intrusion of tooth.
DIAGNOSTICS ■■ ■■
■■
Complete oral examination. Intraoral radiography: full mouth. •• It is imperative to establish if any tooth remains submerged. Appropriate preoperative diagnostics when indicated prior to procedure.
THERAPEUTICS Procedures ■■ ■■ ■■
Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures. Any mechanical barrier to continued eruption should be removed. •• Operculum: excise gingiva covering the crown but retain sufficient attached gingiva (at least 2–3 mm) (Figures 13.4 and 13.5). ◦◦ Cold steel (scissors, blade). ◦◦ Electrocautery (fully rectified): avoid injuring underlying structures. ◦◦ Laser (appropriate use). ◦◦ Gingivectomy bur (12‐fluted or 12‐bladed bur on high‐speed handpiece with adequate coolant). ◦◦ Since teeth are frequently erupted, further eruption is unlikely.
■■ Figure 13.4 Extensive operculum covering left mandibular premolars and molars.
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■■ Figure 13.5 Operculectomy excision with flap repositioned and closed.
•• Unerupted ◦◦ Assess structure to see if efforts to “repair” condition are reasonable. ⋄⋄ Strategic tooth: important structure or function (canine teeth, maxillary fourth premolars, mandibular first molars). ⋄⋄ Determine if potential for eruption is still present (open apex). ▪▪ If the apex has already matured and closed, further eruption would not be expected, even if the mechanical interference is released. Extensive orthodontic efforts may help to extrude the tooth, but such measures are generally not recommended. ▪▪ Extraction of tooth with closed apex may be considered. ▴▴ If any indication of a cystic formation around the tooth is present, extraction and curettage of the site is essential (see Chapter 17). ▴▴ If imbedded for a significant amount of time without cystic or other pathologic changes, and if extraction would extensively damage surrounding bone, continued monitoring may be sufficient.
COMMENTS Expected Course and Prognosis ■■
■■
Simple procedures (operculectomy): fair to good prognosis. •• Continue to monitor periodontal sulcus depth. Unerupted teeth with open apices: fair prognosis depending on extent of involvement. •• Extraction may be necessary if no resolution.
See also the following chapters: Chapter 14 ■■ Chapter 17 ■■
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Abbreviations ■■ ■■ ■■ ■■ ■■
ANO = anodontia HYP = hypodontia T/E = embedded tooth T/I = impacted tooth T/U = unerupted tooth
Suggested Reading Aller S. Retained deciduous teeth and delayed development of dentition of Tibetan terriers. Proceed Vet Dental Forum, Las Vegas, NV 1990:75–78.
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
14
Abnormal Number of Teeth (Decreased) DEFINITION/OVERVIEW ■■
■■ ■■ ■■
Absence of tooth or teeth due to developmental conditions, not to trauma or extraction. •• Anodontia (ANO): failure of all teeth to develop. •• Hypodontia (HYP): developmental absence of a few teeth. •• Oligodontia (OLI): developmental absence of numerous teeth. •• Edentulous (“without teeth”): primarily due to tooth loss (e.g. end‐stage periodontal disease). In dogs, premolars or distal molars are the most common missing teeth (Figure 14.1). If a deciduous tooth is missing, its permanent successor will probably not develop as well. When a permanent tooth is missing, and the deciduous tooth is still present (persistent), if root structure is still stable, that deciduous tooth might stay functional for a long time; lack of a permanent tooth should be documented.
ETIOLOGY/PATHOPHYSIOLOGY ■■
Dog/cat •• Hypodontia, oligodontia, and anodontia: typically hereditary and may be associated with ectodermal dysplasia (hairless dog breeds). •• Bilateral patterns of missing teeth may be indicative of a genetic or familial tendency, as opposed to a single missing tooth.
■■ Figure 14.1 Bilaterally missing mandibular first premolar, confirmed radiographically.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 131
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SIGNALMENT/HISTORY ■■ ■■
Any breed, size, or gender, but smaller breeds predominate. Some familial tendencies, breed prevalence.
CLINICAL FEATURES ■■ ■■
■■
Tooth not present (crown and root). Alveolar bone and gingival margin at site is regular, smooth, even slightly “scalloped” appearance. No tooth structure present radiographically.
DIFFERENTIAL DIAGNOSIS ■■ ■■ ■■ ■■ ■■
Delayed eruption. Unerupted teeth (see Chapter 13). Invulsed tooth. Extracted or lost due to periodontal disease or trauma. Fusion tooth: if two teeth have fused, there will be a reduction in the tooth number (see Chapter 16).
DIAGNOSTICS ■■ ■■ ■■
Complete oral examination. Appropriate preoperative diagnostics when indicated prior to procedure. Intraoral radiographs essential. •• Determine if teeth are truly missing and/or if permanent teeth are present (Figure 14.2). •• Pre‐purchase full mouth radiographs on eight‐ to ten‐week‐old puppies can identify if permanent tooth structures are present (though there is no guarantee they will erupt).
THERAPEUTICS Procedures ■■ ■■ ■■ ■■
Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures. None indicated unless an unerupted or involved tooth is found radiographically. Consider removing from breeding stock.
COMMENTS ■■
In some breeds (Doberman pinschers, rottweilers) or Schutzhund‐trained dogs, any missing teeth may be considered a serious fault, and pre‐purchase radiographs on puppies may be helpful.
See also the following chapters: Chapter 13 ■■ Chapter 16 ■■
chapter 14 Abnormal Number of Teeth (Decreased)
(a)
133
(b)
(c)
(d)
■■ Figure 14.2 Nine‐month old Chinese crested presented (for neutering) with 11 permanent incisors and permanent molars; the remaining teeth were deciduous. (a) Permanent maxillary incisors in contrast to small deciduous canines and premolars. (b) Deciduous mandibular premolars in front of the permanent first molar. (c) Radiograph of mandibular premolars showing no permanent replacements with relatively stable deciduous premolars. (d) Radiograph of mandibular incisors shows five permanent incisors (the left first mandibular incisor is a deciduous one with resorbing root; it was extracted); the canines are deciduous, but with no permanent successor, they were kept.
Abbreviations ■■ ■■ ■■
ANO = anodontia HYP = hypodontia OLI = oligodontia
Suggested Reading Lobprise HB, Dodd JR, eds. Wiggs’ Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019.
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
15 Abnormal Number of Teeth (Increased) DEFINITION/OVERVIEW
■■ ■■ ■■
Increased number of teeth from the normal anticipated dentition. Supernumerary tooth (T/SN): presence of an extra tooth (also called hyperdontia). Gemination (T/GEM): a single tooth bud’s attempt to divide. •• Partially (cleft of the crown). •• Completely (presence of an identical supernumerary tooth; also called twinning).
ETIOLOGY/PATHOPHYSIOLOGY ■■
Dog/cat •• During tooth development (where the dental lamina forms the tooth bud), stimulation – possibly trauma at times – can cause additional bud formation or duplication of an existing bud (twinning). •• If the twinning bud fails to split from the initial structure, a gemination tooth may result (see Chapter 16).
SIGNALMENT/HISTORY ■■ ■■ ■■
Can occur in any breed, size, or gender. Breed prevalence: boxers, bulldogs. Apparent at time of permanent tooth eruption: the presence of supernumerary deciduous teeth requires radiographs since additional supernumerary permanent teeth may have delayed eruption.
CLINICAL FEATURES ■■
Increased number of teeth, frequently involving crowding and/or rotation, or displacement of the supernumerary teeth (Figure 15.1).
Dogs ■■
Not uncommon
Cats ■■
Uncommon for actual supernumerary teeth; gemination of mandibular fourth premolar slightly more common (Figure 15.2).
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 134
CHAPTER 15 ABNORMAL NUMBER OF TEETH (INCREASED)
■■ Figure 15.1 Bilateral supernumerary mandibular third incisors with crowding.
■■ Figure 15.2 Supernumerary right mandibular fourth premolars in a cat.
DIFFERENTIAL DIAGNOSIS ■■ ■■ ■■
Persistent (retained) deciduous teeth (DT/P) (see Chapter 10). Gemination tooth (T/GEM). Odontoma (compound, with tooth structure present) (see Chapter 30).
DIAGNOSTICS ■■
■■
■■
Complete oral examination. •• Identify, count, and chart teeth. •• Distinguish “normal” tooth from supernumerary tooth. •• Determine if any consequences from crowding might occur. Intraoral radiographs (Figures 15.3 and 15.4). •• Assess root structure. •• Determine effect of crowding on bone mass. •• Presence of additional, unerupted supernumerary teeth. Appropriate preoperative diagnostics when indicated prior to procedure.
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■■ Figure 15.3 Radiograph of a cat mandible with indistinct tooth structure causing displacement and periodontal bone loss at the left mandibular fourth premolar.
■■ Figure 15.4 Once the fourth premolar is extracted, the retained roots of the supernumerary fourth premolar are more readily apparent and ready for extraction.
THERAPEUTICS Procedures ■■
■■ ■■ ■■ ■■
Assess extent of crowding and tooth malposition and potential impact on periodontal health; if well spaced with no crowding, the teeth may remain (Figure 15.5). Extract supernumerary teeth if problems are anticipated. Extract embedded supernumerary teeth. Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures.
CHAPTER 15 ABNORMAL NUMBER OF TEETH (INCREASED)
137
■■ Figure 15.5 Even with two supernumerary maxillary incisors there is no crowding so no intervention is necessary.
COMMENTS ■■
Supernumerary teeth that are not problematic may be left.
Expected Course and Prognosis ■■
Uneventful with extractions when appropriate.
See also the following chapter: Chapter 16
■■
Abbreviations ■■ ■■ ■■
DT/P = persistent deciduous tooth T/GEM = gemination tooth T/SN = supernumerary tooth
Suggested Reading Lobprise HB, Dodd JR, eds. Wiggs’ Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019.
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
16 Abnormal Tooth Formation/Structure DEFINITION/OVERVIEW
■■
■■
Variation in tooth size •• Macrodontia (T/MAC): tooth/teeth are larger than normal. •• Microdontia (T/MIC): tooth/teeth are smaller than normal. •• Peg tooth: small cone‐shaped tooth with a single cusp. Variation in tooth structure/shape •• Fusion (T/FUS): combining of adjacent tooth germs and resulting in partial or complete union of the developing teeth; also called synodontia. •• Gemination (T/GEM): a single tooth bud’s attempt to divide partially (cleft of the crown) or completely (presence of an identical supernumerary tooth; also called twinning). •• Dilacerated (T/DIL): disturbance in tooth development, causing the crown or root to be abruptly bent or crooked. •• Carnassial tooth malformation anomalies of the permanent mandibular first molars and deciduous second molars may include normal crowns with a constricted cervical region and thin, narrow, and short roots. ◦◦ Small breed‐dogs: mandibular first molar abnormalities with crown–root disruption and converging roots; often nonvital. •• Dens invaginatus (tooth within a tooth, T/DEN): invagination of the outer surface of a tooth into the interior, occurring in either the crown (involving the pulp chamber) or the root (involving the root canal); also called dens in dente. •• Transposition (T/TRA): two teeth that have exchanged position. •• Concrescence (T/CCR): fusion of the roots of two or more teeth at the cementum level. •• Fused roots (T/FDR): fusion of roots of the same tooth. •• Supernumerary root (T/SR): presence of an extra root. •• Shell teeth: crown present, but little to no root development. •• Amelogenesis imperfecta: hereditary reduction in the amount of developed enamel matrix.
ETIOLOGY/PATHOPHYSIOLOGY ■■
■■ ■■
Stress or stimulus (trauma) at time of development can alter tooth formation. •• Infection, trauma to tooth buds, or traumatic extraction of deciduous teeth during permanent tooth formation can significantly alter the structure. Genetic or familial tendencies not known for most conditions. Dogs/cats.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 138
CHAPTER 16 ABNORMAL TOOTH FORMATION/STRUCTURE
139
CLINICAL FEATURES ■■ ■■
■■
■■
See section Definition/Overview. Fusion: fused crown will be larger than a single tooth; there will be a reduced number of teeth (two counted as one). Gemination tooth, partial: actual number of teeth will be unaltered, but one tooth will be larger, with duplication of part of the crown (and possibly roots radiographically); “Siamese twin.” Dilacerated teeth •• Any variation in structure or form: extra root, curved root. •• Each tooth must be evaluated for integrity of the pulp system, as any disruption in the continuity of the crown and roots may result in exposure of the pulp to the external environment (Figure 16.1).
DIFFERENTIAL DIAGNOSIS ■■ ■■
Trauma to tooth structures Developmental abnormalities
DIAGNOSTICS ■■ ■■
■■
Complete oral examination. Intraoral radiographs: with any abnormal structure (dilaceration), pulpal integrity and the potential for crowding must be evaluated. Appropriate preoperative diagnostics when indicated prior to procedure.
THERAPEUTICS Procedures ■■ ■■
Appropriate antimicrobial and pain management therapy when indicated. Appropriate patient monitoring and support during anesthetic procedures.
■■ Figure 16.1 Extensive dilaceration at the palatal aspect of the right maxillary first molar. Pulpal exposure and compromise is likely.
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SECTION III ORAL/DENTAL DISEASES: DEVELOPMENTAL ORAL/DENTAL PROBLEMS
Fusion teeth: no treatment is necessary unless the groove between the two teeth and/or crowns extends to the gingival margin or below (nidus for periodontal disease). Gemination tooth: if tooth crowding results, extraction may be necessary. Dilacerated tooth: if there is pulpal exposure or compromise, extraction is generally necessary. In some cases, endodontic and restorative therapy may allow preservation of the tooth.
COMMENTS ■■
Abnormal development of mandibular first molars in small‐breed dogs. •• Dilaceration is more common, sometimes described as dens in dente, but most recently referred to as possible carnassial tooth malformation. •• As one of the first permanent teeth to form, there may be a mechanical challenge (lack of space) in small dogs that impedes proper crown–root development. •• Invagination of the enamel and/or cementum at the neck of the tooth, often with some degree of gingival recession (Figure 16.2). •• Radiographic signs (Figure 16.3). ◦◦ Discontinuity between crowns and roots. ◦◦ Possible pulp exposure and pulp stones. ◦◦ Roots are convergent with wide canals (nonvital pulp). ◦◦ Periapical/root abscessation with extensive bone loss.
Expected Course and Prognosis ■■ ■■
Good prognosis on teeth with moderate changes (peg teeth, fusion teeth, gemination tooth). Guarded prognosis on dilacerated teeth with pulpal compromise, though extraction typically successful.
■■ Figure 16.2 Small‐breed abnormal mandibular first molar with defect at the neck of the tooth.
CHAPTER 16 ABNORMAL TOOTH FORMATION/STRUCTURE
141
■■ Figure 16.3 Radiograph of abnormal mandibular first molar with slight convergence of roots, pulpal stone (endolith) in crown, wide root canals, and periapical bone loss.
Abbreviations ■■ ■■ ■■ ■■ ■■
T/CCR = concrescence T/DEN = dens invaginatus T/DIL = dilaceration T/FDR = fused roots T/FUS = fusion
■■ ■■ ■■ ■■ ■■
T/GEM = gemination T/MAC = macrodontia T/MIC = microdontia T/SR = supernumerary root T/TRA = transposition
Suggested Reading Lobprise HB, Dodd JR, eds. Wiggs’ Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019. Regezi JA, Sciubba JJ, Jordan RCK. Oral Pathology: Clinical Pathologic Correlations, 4th edn. St. Louis, MO: Saunders, 1999:367–370.
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
17 Dentigerous Cyst
DEFINITION/OVERVIEW ■■
Cyst formation arising from the soft tissues attached to the crown of an unerupted tooth.
ETIOLOGY/PATHOPHYSIOLOGY ■■
Dogs/cats: any breed which is at an increased risk for impaired eruption (see Chapter 13).
SIGNALMENT/HISTORY ■■ ■■ ■■
See previous section. Boxer, bulldogs: mandibular first premolars, often bilateral. Unerupted teeth at six to seven months of age, but cystic development may not occur until much later, if at all.
CLINICAL FEATURES Dogs ■■ ■■ ■■
■■
Cystic changes may be clinically unapparent without diagnostic imaging. “Missing” tooth. Formation of a nonpainful soft swelling at the site of a missing tooth, often fluctuant with fluid (Figure 17.1). Patient may present, with no previous indications, for a pathologic fracture of the mandible due to cystic expansion and secondary resorption of surrounding bone.
Cats ■■
Uncommon
DIFFERENTIAL DIAGNOSIS ■■
■■
Odontogenic keratocyst: cysts of the jaws demonstrating aggressive expansion which may, or may not, be associated with unerupted teeth. Primordial cyst: cystic degeneration of tooth bud before enamel/dentin formation (cyst without a tooth).
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 142
CHAPTER 17 DENTIGEROUS CYST
143
■■ Figure 17.1 Formation of a nonpainful soft swelling at the site of a missing tooth, often fluctuant with fluid.
■■ Figure 17.2 Radiolucent unilocular (single‐compartment) cyst originating from the remnant enamel organ at the neck of the tooth and encompassing the crown.
■■
■■
Oral mass (odontoma – complex or compound): tooth structures (enamel, dentin, cementum, and pulp) sometimes contained within cystic structure, but with different levels of organization. Transformation to ameloblastomas has been reported in humans; histological evaluation of the cyst lining at the time of removal is highly recommended.
DIAGNOSTICS ■■ ■■ ■■
Radiographs are essential in any instances of missing/unerupted teeth. Definitive diagnosis from radiography. Radiographs show radiolucent unilocular (single‐compartment) cyst originating from the remnant enamel organ at the neck of the tooth and encompassing the crown (Figure 17.2). •• Unerupted teeth are commonly seen to be oriented horizontally.
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Computed tomographic studies of the head should evaluate for presence of unerupted teeth and may be more sensitive for demonstrating early bone resorption. Histopathologic assessment is required if there are atypical radiographic findings; any unerupted teeth demonstrating radiolucency surrounding the unerupted crown should be submitted for histologic evaluation. Appropriate preoperative diagnostics when indicated prior to procedure for safe administration of general anesthesia.
THERAPEUTICS Drugs ■■ ■■
Appropriate antimicrobial therapy is indicated if radiographic evidence of osteomyelitis. Appropriate pain management therapy following removal of the unerupted tooth and enucleated cyst.
Procedures ■■ ■■
■■
■■
Appropriate patient monitoring and support during anesthetic procedures. If any indication of cystic formation is present. •• Surgical extraction of the unerupted tooth (Figure 17.3). •• Complete debridement of cystic lining and histologic evaluation. •• If cystic expansion results in root resorption or compromise to a neighboring tooth’s apical blood supply, extraction or endodontic therapy is indicated. If an embedded tooth has been present in a mature animal: •• Assess for any cystic structure or other pathologic lesions involving the tooth. •• Continued monitoring with radiographs every 6–12 months may be reasonable if surgical extraction would damage large amounts of bone. If a nonstrategic tooth can be easily extracted, it would be best to do so, even if cystic changes are not present.
(a)
(b)
■■ Figure 17.3 (a, b) Surgical extraction of an unerupted tooth.
CHAPTER 17 DENTIGEROUS CYST
145
COMMENTS Expected Course and Prognosis ■■ ■■ ■■
Extraction should be performed to avoid risk for future cyst development. Good with early detection and extraction. Fair to guarded with extensive bone destruction or pathologic fracture.
Possible Complications ■■ ■■ ■■
Pathologic fracture may occur if dentigerous cyst is not diagnosed and treated. Fracture of mandible at time of extraction, due to compromised supporting bone. Cyst development and expansion results in weakening of the bone at that location and may risk causing root resorption of devitalization of neighboring teeth.
See also the following chapter: Chapter 13
■■
Suggested Reading Babbitt SG, Krakowski Volker M, Luskin IR. Incidence of radiographic cystic lesions associated with unerupted teeth in dogs. J Vet Dent 2016;33(4):226–233. Chamberlain TP, Verstraete FJM. Clinical behaviour and managent of odontogenic cysts. In: Verstraete FJM, Lommer MJ, eds. Oral and Maxillofacial Surgery in Dogs and Cats. New York: Saunders Elsevier, 2012:481–486. Soukup J, Lewis JR. Oral and maxillofacial tumors, cysts and tumor‐like lesions. In: Lobprise HB, Dodd JR, eds. Wiggs’s Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019:131–154. Verstraete FJM, Zin BP, Kass PH, et al. Clinical signs and histologic findings in dogs with odontogenic cysts: 41 cases (1795–2010). J Am Vet Med Assoc 2011;239(11):1470–1476.
Internet Resources https://avdc.org/primary‐care‐practice/ to download a pdf of abbreviations (accessed 22 August 2020)
Author: Christopher J. Snyder, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
18 Palatal Defects
DEFINITION/OVERVIEW ■■
Communication between the nasal and oral cavities.
ETIOLOGY/PATHOPHYSIOLOGY ■■
■■
■■ ■■ ■■ ■■ ■■
■■
Secondary to congenital cleft of the secondary palate to include the hard and/or soft palate. •• Failure of the palatine shelves to fuse during development at 25–28 days of gestation. Secondary to a traumatic injury causing disruption of the lateral maxilla and/or hard palate. •• Foreign body, vehicular, or bite trauma. Secondary to resective surgery for neoplasms of the lateral maxilla and/or hard palate. Secondary to extraction of maxillary canine and rostral premolar teeth (see Chapter 22). Wound dehiscence following maxillofacial reconstructive surgery. Genetics: may be inherited or secondary to intrauterine abnormality. Incidence/prevalence: •• Primary cleft palate is an abnormality of the lip and premaxilla and is rarely associated with a palatal defect communicating with the nasal cavity. •• Brachycephalic breeds are predisposed to primary cleft palate. •• Breed predilection for congenital cleft of the secondary palate. Risk factors: •• Inherited (recessive or irregular dominant, polygenic). •• Nutritional. •• Hormonal (steroids). •• In utero abnormality. •• Viral.
SIGNALMENT/HISTORY ■■ ■■
■■ ■■
Species: dogs more common than cats. Breed predilections: brachycephalic breeds, miniature Schnauzer, beagle, cocker spaniel, dachshund, and Siamese cats. Mean age and range: at birth in dogs with primary or secondary cleft palate. History/signs: •• Difficulty nursing. •• Regurgitation. •• Nasal discharge, often mucopurulent.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 146
CHAPTER 18 PALATAL DEFECTS
•• •• •• •• •• ••
147
Sneezing. Gagging when drinking water or eating. Poor growth. Lethargy and depression in chronic cases with severe secondary rhinitis. Cough in cases of secondary aspiration pneumonia. Similar signs reported following trauma or oncologic surgery.
CLINICAL FEATURES ■■ ■■ ■■ ■■ ■■
Hard and/or soft palate defect communicating with the nasal cavity. Nasal discharge. Thoracic auscultation for aspiration pneumonia. Patient is “poor doer.” Check for other congenital abnormalities.
DIFFERENTIAL DIAGNOSIS ■■
Fungal or bacterial rhinitis
DIAGNOSTICS ■■ ■■
■■ ■■
Sedated oral examination. Complete blood count (CBC), biochemistry, and urinalysis: CBC may reflect secondary chronic rhinitis and/or secondary aspiration pneumonia. Consider aerobic bacterial culture and sensitivity of nasal tissue in chronic cases. Imaging •• Thoracic radiographs are recommended to rule out aspiration pneumonia. •• Magnetic resonance imaging (MRI) or computed tomography (CT) is recommended prior to oncologic surgery for imaging of the maxillary/palatal lesion. •• Three‐view thoracic radiographs are recommended to check for distant metastasis before operating on patients with neoplasms.
THERAPEUTICS Drugs ■■
Not applicable, unless treating preoperative rhinitis.
Diet ■■
■■
Preoperative diet should be small dogfood (“meatballs”) fed by hand, or a diet with a consistency that does not cause potential aspiration pneumonia. Postoperative diet should be a thick liquid consistency for the first two weeks.
Procedures: Surgical Considerations ■■
■■
■■
The surgical goal is to provide a soft tissue barrier or layer to reestablish and segregate the oral and nasal cavities. Congenital secondary cleft palate: recommend using a sliding bipedicle flap or an overlapping flap repair technique (Figure 18.1). Traumatic palatal defect: either a buccal mucosal flap repair technique or hard palate mucoperiosteal flap repair technique is recommended (Figure 18.2).
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(a)
(b)
■■ Figure 18.1 (a) Overlapping flap technique for congenital secondary cleft palate. (b) The three‐week postoperative view shows primary healing of the apposed flap and reepithelialization over the hard palate defect.
(a)
(b)
■■ Figure 18.2 (a) Chronic oronasal communication secondary to gunshot trauma. (b) The defect was repaired using a transposition flap incorporating hard and soft palate tissue.
■■
■■
■■
Palatal defect following oncologic surgery: either a buccal mucosal flap repair technique and/or hard palate mucoperiosteal flap repair technique is recommended (Figure 18.3). Palatal defect following maxillofacial reconstruction dehiscence: either a buccal mucosal flap repair technique and/or hard palate mucoperiosteal flap repair technique is recommended (Figure 18.4). A permanent silastic obturator may be used to occlude small palatal defects in refractory cases where surgery has failed multiple times (Figure 18.5).
(a)
(b)
■■ Figure 18.3 (a) Buccal mucosal flap elevated for (b) closure of a lateral hard and soft palate defect following resection of an acanthomatous ameloblastoma lesion.
(a)
(b)
■■ Figure 18.4 (a) Oronasal communication (arrow) following maxillectomy for fibrosarcoma. (b) An island hard palate mucoperiosteal flap was rotated over the defect and sutured. The rostral edge of the flap (arrowheads) was allowed to heal by second intention. Reepithelialization would be expected over the exposed hard palate.
(a)
(b)
■■ Figure 18.5 (a) Chronic oronasal communication in a cat. (b) A silastic nasoseptal defect repair device used in humans was modified as an obturator that remained in place at six months following placement.
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SECTION III ORAL/DENTAL DISEASES: DEVELOPMENTAL ORAL/DENTAL PROBLEMS
COMMENTS ■■
■■
■■
Dogs with primary or secondary cleft palate should be neutered since the condition is considered to be inherited. Lavage the nasal cavity before surgery to remove any foreign material or debris that may have accumulated in the nose. Client education •• A palatal defect requires surgery for repair. •• Multiple surgeries may be required to repair the palatal defect. •• Medical management is ineffective and is only indicated when multiple surgical attempts to repair the palatal defect have failed. •• There is a higher surgical success rate in older puppies. •• Tube feeding may be required for the neonatal patient until surgery, or until the patient can eat a diet of appropriate consistency. •• Secondary rhinitis is expected and self‐limiting with clinical signs more of a nuisance than pathologic. •• Initial dietary management and feeding by the owner is labor intensive.
Expected Course and Prognosis ■■ ■■ ■■
■■ ■■ ■■
Surgery is usually successful, although multiple surgical procedures may be required. The overall prognosis is good. Recommend two‐ and four‐week postoperative examinations to determine success of the surgical procedure. Chew toys and other objects are prohibited for the first eight weeks postoperatively. Secondary rhinitis is usually self‐limiting and resolves following surgical repair. Long‐term (four to six weeks) antimicrobial therapy based on culture and sensitivity may be necessary to treat the chronic rhinitis.
Possible Complications ■■ ■■
Wound dehiscence and failure to repair the palatal defect. Chronic preexisting rhinitis may require extended postoperative antimicrobial therapy.
See also the following chapter: Chapter 22
■■
Abbreviations ■■ ■■ ■■
CBC = complete blood count CT = computed tomography MRI = magnetic resonance imaging
Suggested Reading Hedlund CS. Surgery of the oral cavity and oropharynx. In: Fossum TW, et al., eds. Small Animal Surgery. St. Louis, MO: Mosby, 1997:210–215. Manfra Marretta S, Grove TK, Grillo JF. Split palatal U‐flap: a new technique for repair of caudal hard palate defects. J Vet Dent 1991;8:5–8. Smith MM. Island mucoperiosteal flap for repair of oronasal fistula in a dog. J Vet Dent 2001;18:140–144. Smith MM, Rockhill AD. Prosthodontic appliance for repair of oronasal fistula in a cat. J Am Vet Med Assoc 1996;208:1410–1412.
Author: Mark M. Smith, VMD, DAVDC, DACVS Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Chapter
19
Malocclusions: Skeletal and Dental DEFINITION/OVERVIEW ■■
■■
A malocclusion (MAL) is any deviation from a normal occlusion, due to skeletal influences (asymmetry or other deviation of bone that support the teeth) or an abnormal positioning of a tooth or teeth (dental malocclusion). Ideal occlusion: perfect interdigitation of maxillary and mandibular teeth (see Appendix C, Classification of Dental Occlusion in Dogs) (Figure 19.1). •• The ideal tooth positions in the arches are defined by the occlusal, inter‐arch, and interdental relationships of the teeth of the archetypal dog (i.e. wolf). This ideal relationship with the mouth closed can be defined by the following. •• Maxillary incisors are positioned rostral to the corresponding mandibular incisors. ◦◦ Crown cusps of mandibular incisors contact the cingulum of the maxillary incisors (“scissor bite”). •• Mandibular canines incline labially and are positioned equidistantly between the maxillary third incisor and canine in the interdental (interproximal) space (bisect the diastema). •• Maxillary premolars do not contact the mandibular premolars. ◦◦ Crown cusps of the mandibular premolars are positioned lingual to the arch of the maxillary premolars. ◦◦ Crown cusps of mandibular premolars bisect the interproximal (interdental) spaces rostral to the corresponding maxillary premolars (“pinking shear” configuration).
■■ Figure 19.1 An ideal occlusion on a model.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 151
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SECTION III ORAL/DENTAL DISEASES: DEVELOPMENTAL ORAL/DENTAL PROBLEMS
•• Maxillary fourth premolar’s mesial cusp is positioned lateral to the space between the mandibular fourth premolar and first molar. Normal occlusion in a cat is similar to that of a dog with some distinctions. •• Each mandibular premolar tooth is positioned mesial to the corresponding maxillary premolar tooth. •• The maxillary second premolar tooth points in a space between the mandibular canine tooth and third premolar tooth. •• The subsequent teeth interdigitate, with the mandibular premolars and first molar being situated lingual to the maxillary teeth. •• The buccal surface of the mandibular first molar tooth occludes with the palatal s urface of the maxillary fourth premolar tooth. •• The maxillary first molar tooth is located distopalatal to the maxillary fourth premolar tooth. Malocclusion may be present in deciduous or permanent teeth. •• Deciduous malocclusions are best evaluated by incisor and canine positioning; spacing of the decreased number of deciduous premolars and molars may vary (Figure 19.2). •• Continual growth of the jaw quadrants requires regular reassessment. Terms of malocclusion (AVDC nomenclature). •• Neutroclusion: Class 1 malocclusion (MAL1) (dental malocclusions). ◦◦ Normal rostral–caudal relationship of the maxillary and mandibular dental arches. ◦◦ Malposition of one or more individual teeth. ⋄⋄ Dental malocclusion: tooth in anatomically correct position in the dental arch, but: ▪▪ Distoversion (MAL1/DV): abnormally angled in a distal direction (“snake tooth”). ▪▪ Mesioversion (MAL1/MV): abnormally angled in a mesial direction (“lance tooth”). ▪▪ Linguoversion (MAL1/LV): abnormally angled in a lingual direction (“base‐narrow mandibular canine”) (Figure 19.3). ▪▪ Palatoversion (MAL1/PV): abnormally angled in a palatal direction (maxillary teeth).
■■ Figure 19.2 Evaluating a deciduous malocclusion by assessing incisor and canine position.
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■■ Figure 19.3 Labioversion of 404, with tip of crown contacting palate; (mild MAL2)
▪▪ Labioversion (MAL1/LABV): incisors or canines abnormally angled in a labial direction. ▪▪ Buccoversion (MAL1/BV): premolars or molars abnormally angled in a buccal direction. ⋄⋄ Crossbite (CB): mandibular tooth/teeth have a more buccal or labial position than antagonist maxillary tooth. ▪▪ Rostral crossbite (CB/R): one or more of the mandibular incisor teeth is labial to the opposing maxillary incisor teeth when the mouth is closed. Similar to anterior crossbite in human terminology. ▪▪ Caudal crossbite (CB/C): one or more of the mandibular cheek teeth is buccal to the opposing maxillary cheek teeth when the mouth is closed. Similar to posterior crossbite in human terminology. •• Mandibular distoclusion: Class 2 malocclusion (MAL2) (skeletal symmetrical malocclusion). ◦◦ An abnormal rostrocaudal relationship between the dental arches in which the mandibular arch occludes caudal to its normal position relative to the maxillary arch (Figure 19.4). Also called “mandibular brachygnathism” or “overshot.” •• Mandibular mesioclusion: Class 3 malocclusion (MAL3) (skeletal symmetrical malocclusion). ◦◦ An abnormal rostralcaudal relationship between the dental arches in which the mandibular arch occludes rostral to its normal position relative to the maxillary arch (Figure 19.5). Also called “mandibular prognathism,” “maxillary brachygnathism” or “undershot.” ◦◦ Incisors may still appear to be in scissor bite, but if the mandibular canines are positioned too far mesially, there is likely a mandibular mesioclusion (Figure 19.6). Evaluate remainder of occlusion. •• Asymmetrical skeletal malocclusion. ◦◦ Maxillomandibular asymmetry: Class 4 malocclusion (MAL4) (asymmetry in a rostrocaudal, side‐to‐side, or dorsoventral direction). ⋄⋄ Rostrocaudal direction (MAL4/RC): mandibular mesioclusion or distoclusion present on one side; contralateral side normal alignment. ⋄⋄ Side‐to‐side direction (MAL4/STS): loss of midline alignment of maxilla and mandible.
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■■ Figure 19.4 Significant base‐narrow canine in addition to, or because of, a Class 2 malocclusion (mandible in distoversion). Even with an adequate diastema between the maxillary third incisor and canine, movement would be complicated.
■■ Figure 19.5 Class 3 malocclusion.
■■ Figure 19.6 Mild to moderate mesioversion (rostroversion) of mandibular canine apparent due to rostral placement of mandibular canine, even though incisors still appear to be in a scissor bite. Simple extraction of the third incisor should provide this patient with a comfortable bite.
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⋄⋄ Dorsoventral direction (MAL4/DV): abnormal vertical space between opposing dental arches when the mouth is closed (open bite). ◦◦ “Wry bite”: nonspecific term used to describe a wide variety of unilateral occlusal abnormalities; its use is not recommended.
ETIOLOGY/PATHOPHYSIOLOGY Causes ■■
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Congenital or hereditary factors: skeletal malocclusions (classes 2, 3, and 4) and breed predilection. •• Brachycephalic breeds: Class 3. •• Dolichocephalic breeds: mesioversion maxillary canines, caudal crossbite. Retention (persistent) or delayed loss of deciduous teeth. •• Permanent mandibular canines (and most other teeth) will erupt lingual to persistent deciduous teeth (Figure 19.7). •• The permanent maxillary canine will erupt rostral to the deciduous tooth. Impediment to tooth eruption: operculum (retention of soft tissue covering). Traumatic injury affecting the jaws or teeth.
Risk Factors ■■
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Congenital or hereditary factors: skeletal malocclusions (classes 2, 3 and 4, and asymmetry) and breed predilection. •• Some malocclusions are accepted within a breed standard. Traumatic injury affecting the jaws or teeth, especially during development and growth phases. Mechanical misdirection: •• Tooth eruption contact impediment. •• Delayed loss of deciduous teeth (see Chapter 10) (see Figure 19.7). •• Delayed eruption of deciduous or permanent teeth (see Chapter 13).
■■ Figure 19.7 Delayed loss of deciduous mandibular canines has caused the permanent canines to erupt in a more lingual position.
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SIGNALMENT/HISTORY ■■ ■■ ■■
Can occur in dogs or cats with primary (deciduous) or permanent dentition. No sex predilections. No age predilections, other than malocclusions are typically discernible at the time of, or shortly following, eruption of the deciduous or permanent teeth. •• Significant jaw growth can occur up to six to eight months (and longer in large breeds); full evaluation can only be done once growth is complete.
CLINICAL FEATURES ■■
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Vary greatly according to the type, extent, and consequent injuries caused by the malocclusion (see description of malocclusions in section Definition/Overview). May be associated with open or closed bites or overcrowding of the teeth. Periodontal disease may result due to crowding, rotation, or misalignment of teeth. Soft tissue defects may be seen both in the floor or palate from traumatic tooth contact. •• In the palate the injuries may eventually extend in depth, resulting in oronasal fistula formation. Fractures or attrition of teeth may result from improper tooth contact.
Class 1 Malocclusions ■■
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Rostral (anterior) crossbite: palatoversion of maxillary incisors or labioversion of mandibular incisors. •• Level bite: maxillary and mandibular incisor cusps contact directly. Linguoversion mandibular canine(s) (base‐narrow canines). •• Tips of mandibular canine(s) touch palate lingual to normal contact point, lined up with the diastema between corner incisor and maxillary canine (linguoversion). •• Common sequelae to narrow mandible or delayed exfoliation (persistence) of deciduous mandibular canines. •• Significant trauma to the palate can result. Mesioversion of maxillary canine(s) (rostroversion, lance tooth/teeth). •• With malpositioning of the canine, the diastema between the corner incisor and this canine is often diminished and may force the mandibular canine into an abnormal position. •• Mild to moderate rostroversion due to persistent deciduous tooth: permanent tooth erupts further rostral than normal. •• In dolichocephalic breeds (e.g. shelties and collies), this mesioversion may present as a nearly horizontal positioning of the canine(s). Caudal (posterior) crossbite. •• One or more mandibular cheek teeth buccal to maxillary teeth. •• More common in dolichocephalic breeds (collie).
Class 2, 3, and 4 Malocclusions (Skeletal Malocclusions) ■■
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Class 2: mandible short in relation to maxilla. •• Trauma to palate from mandibular incisors. •• Trauma to palate from mandibular canine, depending on extent of jaw length discrepancy and position in relation to maxillary canine; often in linguoversion (Figure 19.8). Class 3: maxilla short in relation to mandible (brachycephalic). •• Within standards for many brachycephalic breeds. More pronounced malocclusion may be outside breed acceptance.
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■■ Figure 19.8 Class 2 malocclusion with trauma to palate from mandibular canines.
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•• Trauma to floor of mouth and mandibular incisors and canines due to contact from maxillary incisors. •• Maxillary premolars often crowded and rotated, with predisposition to periodontal disease. •• A mild Class 3 malocclusion may be inapparent due to the appearance of an incisor scissor bite; canine and premolar interdigitation is the best way to assess this. ◦◦ If the mandibular canines are tight against maxillary third incisors and the mandibular premolar cusps are mesial to correct positioning, a MAL3 is p resent. Class 4: maxillomandibular asymmetry. •• Varying contact issues, depending on occlusion.
DIFFERENTIAL DIAGNOSIS ■■ ■■
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Tooth displacement due to trauma, oral masses, or other causes. Mechanical block: open bite caused by foreign bodies, luxated or subluxated teeth or jaw fractures, even once healed, if stabilized in an abnormal position. Examine breed standards to determine what might be acceptable for the breed. •• Boxers have a “normal” Class 3 malocclusion, as long as it is not exaggerated.
DIAGNOSTICS ■■ ■■ ■■ ■■ ■■
Based upon visual and radiographic findings. Impressions and models. Oral photographs: before, after, and throughout the treatment time. Radiographs to evaluate roots and abnormalities, jaw anatomy, root maturity. Examine for supernumerary, geminated, or fusion of teeth or roots, retained deciduous teeth, retained roots, luxated teeth, and tooth or jaw fractures or abnormalities.
THERAPEUTICS Drugs ■■
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If correcting with appliances, use oral hygiene products (zinc ascorbate oral gel, oral chlorine dioxide solutions, 0.2% chlorhexidine oral rinse, etc.) during treatment. In most cases anti‐inflammatories and pain medications should be used.
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Procedures Deciduous Tooth Class 1 Malocclusions Careful and gentle extraction of the maloccluded deciduous teeth (preventive or interceptive orthodontics) in hopes that the permanent teeth will erupt in the appropriate position (Figure 19.9). ■■ When performed at least four weeks prior to permanent tooth eruption (at seven to eight weeks of age for incisor malocclusion), success rates of over 80% are common. ■■
Deciduous Tooth Class 2, 3, and 4 Skeletal Malocclusions Careful and gentle extraction of the maloccluded deciduous teeth in hopes that the short jaw(s) will be released from the bite interlock allowing it to grow, if the genetic potential is present, prior to the permanent teeth erupting and bite interlock reestablishing. ■■ Extraction should be performed at least six weeks prior to permanent tooth eruption; even then, success rates below 20% are common in dogs, but are close to 50% in cats (Figure 19.10). ■■
Treatment of Permanent Tooth Malocclusions Not every animal needs orthodontic treatment: if the bite is functional and nontraumatic to the animal, treatment may not be necessary. ■■ Extraction of offending teeth can many times be an effective alternative to more classic orthodontic treatments (Figures 19.11 and 19.12). ■■ Orthodontic treatment is usually based on prevention of improper contact trauma, wear or injury to hard or soft tissues, which may or may not include movement of the tooth into its theoretical proper position. ■■
Permanent Tooth Class 1 Malocclusion Treatment primarily involves tipping movements of the teeth, although extrusion may be required to provide proper retention. ■■ Rostral crossbite: correction for esthetics not recommended. ■■ Linguoversion mandibular canine teeth: prevention of contact trauma, pain and discomfort, and oronasal fistula formation. ■■
■■ Figure 19.9 A Class 2 malocclusion in this puppy was managed by carefully extracting the mandibular canines that were contacting the palate. Assessment of the patient’s occlusion with permanent teeth will be very important (see Figure 19.16).
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■■ Figure 19.10 Brachycephalic feline breeds may present with a deciduous malocclusion involving the canines. Extraction of any canines in malocclusion is needed, and up to 50% of these patients will have a more normal permanent occlusion.
■■ Figure 19.11 Mixed dentition malocclusion with multiple issues: persistent deciduous teeth causing displacement of permanent teeth, contact of permanent canines with incisors, etc.
■■ Figure 19.12 Select extraction of deciduous teeth and any incisors that might be causing crowding or contributing to contact issues are extracted, leaving the patient with a comfortable bite, even though the malocclusion remains.
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•• The maxillary diastema must be sufficient for the mandibular canine to fit; there is natural retention once corrected. •• Early intervention with manual manipulation or “ball therapy” for newly erupting teeth may influence a more buccal position. ◦◦ A hard rubber ball is placed in the mouth to help “slide” the canines laterally; two to three times daily, a few minutes at a time. •• Gingivoplasty in the diastema may release the tooth if there is minimal maxillary mucosal contact (Figure 19.13). •• A composite crown extension can help splay the tip buccal to the gingival margin in moderate cases (Figure 19.14). •• More severe cases may require an orthodontic appliance (incline plane), to be handled by a specialist.
■■ Figure 19.13 With mild linguoversion of mandibular canines, if a gingivoplasty will “release” the crown tip, it may be sufficient therapy.
■■ Figure 19.14 With moderate linguoversion of mandibular canines, additional therapy of placing a composite crown extension to help tip the tooth into a more buccal position may be needed.
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■■ Figure 19.15 With severe linguoversion of mandibular canines, particularly if they are lined up palatal to the maxillary canines, crown reduction with vital pulp therapy or root canal, or extraction may be needed.
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•• Mandibular canine extraction or crown reduction with vital pulp therapy to alleviate discomfort (interceptive orthodontics) (Figure 19.15). Maxillary canine mesioversion (lance tooth) •• If the displacement is mild, but has compromised the diastema, the mandibular canine may be positioned buccally or lingually, with potential contact with the maxillary third incisor. ◦◦ Extraction of the maxillary third incisor may give adequate diastemal space for the mandibular canine. •• Complicated movement; handled by specialist. •• Extract. Caudal crossbite •• In traumatic situations, extraction of one of the offending teeth; orthodontic correction would be long and tedious.
Permanent Tooth Class 2, 3, and 4 Skeletal Malocclusions If malocclusion is functional and nontraumatic, treatment may not be necessary. ■■ Class 2 malocclusion may result in linguoversion of mandibular canines. •• If positioned somewhat rostral to the level of the maxillary canine, orthodontic movement in a rostral and buccal direction may be considered (crown extension, incline plane). •• If positioned level with the maxillary canines, orthodontic movement would be likely unsuccessful, so perform extraction or crown reduction with vital pulp therapy. •• If positioned distal to the level of the maxillary canine, orthodontic movement in a distal and buccal direction may be considered (crown extension, incline plane). The mandibular canine will now be positioned distal to the maxillary canine, but the patient will be more comfortable (Figure 19.16). •• Evaluate the level of trauma the mandibular incisors cause to the palate and treat accordingly. ■■
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■■ Figure 19.16 In the patient with the deciduous malocclusion and interceptive orthodontics (see Figure 19.9), the permanent jaw lengths were still disproportionate. Additional therapy to tip the mandibular canine buccally, and further distally, gave this young dog a comfortable bite.
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Class 3 malocclusion •• If minor, the mandibular canine may contact or occlude palatal to the maxillary third incisor; extraction of the incisor should provide adequate space for the canine. •• If significant, evaluate extent of trauma the incisors cause to the floor of the mouth and mandibular incisors and canines. Class 4 malocclusion •• Evaluate any contact areas; if extensive trauma is caused, consider extraction or crown reduction of offending teeth. Any advanced orthodontic and surgical procedures should be done by a specialist.
COMMENTS ■■
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Complications due to treatment attempts. •• Untreated nonvital teeth. •• Advanced periodontal disease, luxated or mobile teeth. •• Problems with health of oral tissues. Home care with appliance •• Twice‐daily examination of appliance, flushing the mouth with an oral hygiene solution or gel, no chewing of items, and a soft diet until the appliance is removed. Patient monitoring •• For the corrected occlusion to be stable it needs to be self‐retaining or it may tend to revert to malocclusion. •• Patient should be examined at two weeks, two months, and six months post treatment to see if desired outcome is stable. •• At six months post treatment it is advisable for radiographs to be taken and compared to the pretreatment films. ◦◦ Determine if all teeth still appear vital (alive). ◦◦ Evaluate any root changes that may have occurred due to the pressures of tooth/ root movement during orthodontics.
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Prevention/avoidance •• Selective breeding based on preferred breed characteristics. •• Careful monitoring of deciduous and permanent tooth eruption for early detection and treatment, if required. Possible complications •• With selective extractions of deciduous teeth prior to permanent tooth eruption there is a potential for injury to underlying permanent tooth buds either by direct injury with extraction instruments or subsequent traumatic inflammation affecting the development of tooth growth and maturity. •• These injuries may result in teeth becoming nonvital as they erupt, root dysplasia or dilaceration, or crown enamel hypoplasia or hypomineralization. •• With orthodontic movement of permanent teeth several conditions may result, such as unintentional movement of anchor teeth, some degree of root resorption, root ankylosis, or nonvitality of the tooth; these conditions are uncommon in properly managed orthodontic procedures. Associated conditions: lack of head symmetry, oral soft tissue trauma, chipped teeth, desiccation of exposed tooth surfaces, and periodontal disease. Age‐related factors: the condition is typically initially observed at less than 14 months of age and usually shortly following tooth eruption. Ethical considerations •• Although animals have the medical right to as functional and correct an occlusion without discomfort as can be reasonably provided by therapy, animal club rules, professional association principles, state and country laws may at times conflict with the animal’s rights to such medical therapy. Some kennel club rules make animals with modification of natural appearance, with certain exceptions, cause for disqualification and owners should be made aware of this. •• If hereditary involvement is suspected, inform the owner. If treatment is being considered, the owner or agent should acknowledge their responsibilities to inform anyone that has a right to know of such alterations. •• Additionally, the recommendation of possibly removing the animal from the genetic pool by appropriate methods should be suggested.
Expected Course and Prognosis ■■
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Course of treatment can vary with the type of malocclusion and the animal’s nature and habits (chewing, etc.). Generally most cases take one to seven months for movement and retention phase, depending on severity and if extrusion of tooth/teeth is required for stabilization of the bite. Prognosis is good to excellent in most treated patients. Complications in untreated cases typically involve a greater degree of problems with periodontal disease, attrition or fractures of teeth, trauma to soft tissues, oronasal fistula formation, and drying or desiccation of exposed tooth surfaces resulting in beige to brown discoloration of said areas. Some cases do not need or require orthodontic intervention. •• In such cases only routine observation for early detection and treatment of any secondary complications, such as periodontal disease, or worn or chipped teeth is advisable.
See also the following chapter: Appendix C (Classification of Dental Occlusion in Dogs)
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Abbreviations ■■ ■■ ■■ ■■ ■■
BV = buccoversion CB = crossbite CB/C = caudal crossbite CB/R = rostral crossbite DV = distoversion
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LABV = labioversion LV = linguoversion MAL = malocclusion MV = mesioversion PV = palatoversion
Suggested Reading Lobprise HB, Dodd JR, eds. Wiggs’ Veterinary Dentistry: Principles and Practice, 2nd edn. Hoboken, NJ: Wiley Blackwell, 2019.
Author: Heidi B. Lobprise, DVM, DAVDC Consulting Editor: Heidi B. Lobprise, DVM, DAVDC
Section
IV
Acquired Oral/Dental Diseases: Periodontal Problems
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Chapter
20
Periodontal Disease
DEFINITION/OVERVIEW ■■
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Inflammation and destruction of the periodontium (i.e. gingiva, cementum, periodontal ligament, and alveolar bone) secondary to the complex community of bacteria of the subgingival plaque biofilm and the host inflammatory response. Periodontal disease (PD) may be active or quiescent. Periodontitis is active inflammation of the periodontium and results in loss of the periodontium and periodontal attachment loss. It is estimated to affect up to 85% or more of the domestic canine and feline populations over the age of two to three years. An important clinical note: periodontal disease is a subgingival disease with loss of attachment of the periodontium. The clinical appearance of the crowns of the teeth cannot adequately assess and diagnose changes in the periodontium. General anesthesia, dental imaging (i.e. intraoral radiology and/or cone beam computed tomography), and periodontal probing and examination to assess the subgingival periodontal tissues are necessary for assessment and diagnosis.
ETIOLOGY/PATHOPHYSIOLOGY Pathophysiology ■■
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Begins as a juvenile, with the eruption of the adult dentition. It continues throughout all life stages of the animal in association with the plaque biofilm and host inflammatory response. In the ideal oral cavity, oral homeostasis would be maintained. However, many factors disrupt the equilibrium of oral bacteria and the host physiological mechanisms resulting in periodontitis. A pellicle of salivary glycoproteins adheres to the clean tooth and colonizing Gram‐positive aerobic bacteria attach first, creating the plaque biofilm. The supragingival plaque biofilm matures and influences the development of the subgingival biofilm. The intact junctional epithelium barrier at the base of the gingival sulcus and the high rate of epithelial turnover, with surface desquamation, help prevent bacteria from gaining direct access to more apical periodontal tissues in a homeostatic state. The constituents of the biofilm progress to include Gram‐negative anaerobic, motile, and spirochete bacteria. The biofilm forms within days and will mature within weeks. Bacterial byproducts and proteolytic enzymes, along with the host inflammatory response, cause destruction of the periodontium resulting in the loss of attachment for the tooth.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dentistry, Third Edition. Edited by Heidi B. Lobprise. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/lobprise/dentistry 167
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Tissues may become edematous and/or exhibit gingival hyperplasia/enlargement. There may be exocytosis of inflammatory cells such as lymphocytes, plasma cells, and polymorphonuclear leukocytes, abundant colonies of bacterial microorganisms, areas of fibrosis, edema, and hemorrhage in the gingival and periodontal ligament tissues. Bone may demonstrate infiltration of inflammatory cells. Bone resorption with both osteoclastic and osteoblastic activity is present. Osteomyelitis/osteitis can result. Calculus is the mineralization of the plaque biofilm. It is rough, acts a surface area for more plaque development, and can be mechanically irritating to the tissues.
Risk Factors ■■
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Small‐breed dogs, brachycephalic breed dogs, sighthounds, long‐facial‐haired dogs, and purebred cat breeds tend to have an increased predilection. Lack of daily preventive home care and professional veterinary dental care. Immunosuppression from pharmaceuticals or metabolic disease affecting systemic health. Other risk factors include, but are not limited to, inappropriate chewing behavior, malocclusions, crowding of dentition, addition of medications, changes in saliva characteristics, and oral foreign bodies.
Local and Systemic Sequelae ■■
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PD affects the tissue of the oral cavity and maxillofacial region, and can result in systemic inflammation and changes in multiple distant organ systems (hepatobiliary, renal, CNS, +/– cardiovascular, endocrine/metabolic – diabetes mellitus regulation). Patients may exhibit behavioral changes (such as being head shy and pawing and rubbing the face due to hidden oral pain), upper respiratory symptoms (nasal discharge and sneezing associated with rhinitis), ophthalmic problems (orbital and periorbital pathology), and musculoskeletal symptoms (maxillofacial swellings and draining tracts, fractured mandible/ maxilla).
SIGNALMENT/HISTORY ■■
Dogs and cats six months and older may be affected. The disease process continues throughout the life stages of the animal.
CLINICAL FEATURES ■■
Clinical signs are often hidden until end‐stage clinical signs manifest. •• Hidden or no clinical signs or presence of halitosis, head shyness, gingival bleeding, dropping food, slow chewing and/or reluctance to chew, pawing at the mouth, exaggerated jaw movements, maxillofacial swellings, ptyalism, sneezing, and nasal discharge.
Physical Examination Findings ■■
Conscious examination •• May or may not have abundant plaque and/or calculus deposits. •• Inflammation of the gingiva, root exposure, furcation exposure, mobile teeth, parulides, disproportionate plaque and calculus distribution, oral discharge, maxillofacial swellings, and mandibular lymphadenopathy. •• The conscious examination significantly underestimates the presence and severity of PD and therefore an anesthetized examination with periodontal probing and intraoral radiographs is required for complete assessment.
chapter 20 Periodontal Disease
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Anesthetized examination: the degree of severity of PD relates to a single tooth; a patient may have teeth that exhibit different stages of PD (Figure 20.1). American Veterinary Dental College (AVDC) nomenclature •• Normal (PD0): clinically normal; gingival inflammation or periodontitis is not clinically evident. •• Stage 1 (PD1): gingivitis only without attachment loss; the height and architecture of the alveolar margin are normal (Figure 20.2).
■■ Figure 20.1 Intraoral radiograph of the dog left maxilla demonstrating each individual tooth patient and periodontal staging. Various teeth in each dental arcade can be at different stages of periodontal attachment loss. The left maxillary second premolar (206) has approximately 50% horizontal bone loss and a stage 3 clinical furcation so classified as PD stage 4. The mesial aspect of the left maxillary third premolar (207) has 25–50% horizontal bone loss and is categorized as PD stage 3. The left maxillary fourth premolar (208) has