Dental Update – October 2020 Volume 47 . Number 9

Table of contents :
701 COMMENT
Begonias
FJ Trevor Burke
703 GUEST EDITORIAL
Dentistry and COVID-19 – Time to Rethink
our Prescribing Patterns?
RL Caplin
706 RESTORATIVE DENTISTRY
Dens Evaginatus – ‘Addition Beats
Subtraction’
K Ayub, S Khan and M Kelleher
CPD Aims, Objectives and Learning
Outcomes: To explain the problems of dens
evaginatus and of modern management
strategies.
Enhanced CPD DO C
714 ORAL SURGERY
Coronectomy: not just for Wisdom Teeth
B Owen, G Oliver, L Macey-Dare and G Knepil
CPD Aims, Objectives and Learning
Outcomes: To present a novel case of
coronectomy to an infra-occluded lower left
first molar coronectomy to avoid inferior
alveolar nerve damage, and facilitate
orthodontic treatment.
Enhanced CPD DO C
719 RESTORATIVE DENTISTRY
A Combined Digital-Conventional Workflow
to Fabricate a Removeable Partial Denture
for a Patient with a Severe Gag Reflex
RB O'Leary and AL Gunderman
CPD Aims, Objectives and Learning
Outcomes: To understand the uses,
advantages and limitations of digital
workflows in fabricating removable partial
dentures.
Enhanced CPD DO C
729 GENERAL DENTISTRY/PAEDIATRIC DENTISTRY/
ORTHODONTICS
Supernumerary Teeth: an Overview for the
General Dental Practitioner
MJ Meade
CPD Aims, Objectives and Learning
Outcomes: To highlight how timely
diagnosis and appropriate management may
reduce potential problems associated with
supernumerary teeth.
Enhanced CPD DO C
739 ORAL SURGERY
Rhinosinusitis Update
C Hopkins
CPD Aims, Objectives and Learning
Outcomes: To review current management
strategies of rhinosinusitis.
Enhanced CPD DO C
747 ENDODONTICS
Controversies in Endodontic Access Cavity
Design: a Literature Review
M Maqbool, TY Noorani, JA Asif, SD Makandar
and N Jamayet
CPD Aims, Objectives and Learning
Outcomes: To compare and contrast the
different types of endodontic access cavity
designs based on the current available
evidence.
Enhanced CPD DO C
755 RADIOLOGY
Update on Ionizing Radiation Regulations
2017 (IRR 2017) and Ionizing Radiation Medical
Exposure Regulations 2018 (IRMER 2018) −
Relevance to the Dental Team
KK Grewal and N Heath
CPD Aims, Objectives and Learning
Outcomes: To understand the new revisions
to IRR and IRMER guidance and appreciate its
implications to dental practice.
Enhanced CPD DO C
761 COVID-19 COMMENTARY
Coronavirus Disease 2019 (COVID-19)
Diagnostics: a Primer
L Samaranayake, N Kinariwala and RAPM Perera
767 LETTERS TO THE EDITOR
769 BREAKING NEWS: COVID-19 AND DENTISTRY
L Samaranayake
770 I LEARNT ABOUT DENTISTRY FROM THAT
771 TECHNIQUE TIPS
The Role of Fibre-reinforced Composite Posts
in Children
AS Dhadwal, SJ McKaig and A Casaus
774 CPD QUESTIONS

Citation preview

DentalUpdate October 2020 . Volume 47 . Number 9

„ Restorative Dentistry: Dens Evaginatus – ‘Addition Beats Subtraction’ „ Oral Surgery: Coronectomy: not just for Wisdom Teeth „ Radiology: Update on Ionizing Radiation Regulations 2017 (IRR 2017) and Ionizing Radiation Medical Exposure Regulations 2018 (IRMER 2018) − Relevance to the Dental Team


 
   
  

   

    
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INSIDE THIS ISSUE 701 COMMENT Begonias FJ Trevor Burke 703 GUEST EDITORIAL Dentistry and COVID-19 – Time to Rethink our Prescribing Patterns? RL Caplin 706 RESTORATIVE DENTISTRY Dens Evaginatus – ‘Addition Beats Subtraction’ K Ayub, S Khan and M Kelleher CPD Aims, Objectives and Learning Outcomes: To explain the problems of dens evaginatus and of modern management strategies. Enhanced CPD DO C 714 ORAL SURGERY Coronectomy: not just for Wisdom Teeth B Owen, G Oliver, L Macey-Dare and G Knepil CPD Aims, Objectives and Learning Outcomes: To present a novel case of coronectomy to an infra-occluded lower left first molar coronectomy to avoid inferior alveolar nerve damage, and facilitate orthodontic treatment. Enhanced CPD DO C 719 RESTORATIVE DENTISTRY A Combined Digital-Conventional Workflow to Fabricate a Removeable Partial Denture for a Patient with a Severe Gag Reflex RB O'Leary and AL Gunderman

CPD Aims, Objectives and Learning Outcomes: To understand the uses, advantages and limitations of digital workflows in fabricating removable partial dentures. Enhanced CPD DO C 729 GENERAL DENTISTRY/PAEDIATRIC DENTISTRY/ ORTHODONTICS Supernumerary Teeth: an Overview for the General Dental Practitioner MJ Meade CPD Aims, Objectives and Learning Outcomes: To highlight how timely diagnosis and appropriate management may reduce potential problems associated with supernumerary teeth. Enhanced CPD DO C 739 ORAL SURGERY Rhinosinusitis Update C Hopkins CPD Aims, Objectives and Learning Outcomes: To review current management strategies of rhinosinusitis. Enhanced CPD DO C

different types of endodontic access cavity designs based on the current available evidence. Enhanced CPD DO C 755 RADIOLOGY Update on Ionizing Radiation Regulations 2017 (IRR 2017) and Ionizing Radiation Medical Exposure Regulations 2018 (IRMER 2018) − Relevance to the Dental Team KK Grewal and N Heath CPD Aims, Objectives and Learning Outcomes: To understand the new revisions to IRR and IRMER guidance and appreciate its implications to dental practice. Enhanced CPD DO C 761 COVID-19 COMMENTARY Coronavirus Disease 2019 (COVID-19) Diagnostics: a Primer L Samaranayake, N Kinariwala and RAPM Perera 767 LETTERS TO THE EDITOR 769 BREAKING NEWS: COVID-19 AND DENTISTRY L Samaranayake 770 I LEARNT ABOUT DENTISTRY FROM THAT

747 ENDODONTICS Controversies in Endodontic Access Cavity Design: a Literature Review M Maqbool, TY Noorani, JA Asif, SD Makandar and N Jamayet CPD Aims, Objectives and Learning Outcomes: To compare and contrast the

771 TECHNIQUE TIPS The Role of Fibre-reinforced Composite Posts in Children AS Dhadwal, SJ McKaig and A Casaus 774 CPD QUESTIONS

CPD in Dental Update in partnership with EDITORIAL DIRECTOR FJ Trevor Burke Professor of Dental Primary Care, University of Birmingham School of Dentistry EXECUTIVE EDITOR Angela Stroud EDITORIAL BOARD Avijit Banerjee Professor of Cariology and Operative Dentistry Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London Subir Banerji Programme Director MSc in Aesthetic Dentistry Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London Steve Bonsor (c/o RCPSG) The Dental Practice 21 Rubislaw Terrace Aberdeen AB10 1XE Andrew Chandrapal GDP, Bourne End Dental

October 2020

Bourne End, Bucks Len D'Cruz GDP, Woodford Dental Care, Woodford Green, Essex Chris Deery Professor of Paediatric Dentistry, School of Clinical Dentistry, Sheffield S10 2TA Ian Dunn Specialist Periodontist Rose Lane Dental Practice Liverpool L18 8AG Ken Hemmings Consultant Eastman Dental Hospital, London WC1X 8LD Edwina Kidd Emerita Board Member c/o George Warman Publications Unit 2, Riverview Business Park, Walnut Tree Close, Guildford GU1 4UX Mike Lewis Professor of Oral Medicine School of Dentistry, Cardiff University Cardiff CF14 4XY

Louis Mackenzie GDP and Clinical Lecturer University of Birmingham School of Dentistry and King's College London Tara Renton Professor of Oral Surgery, King's College London Dental Institute David Ricketts Professor of Cariology and Conservative Dentistry, Dundee Dental Hospital Jonathan Sandler Professor and Consultant Orthodontist, Chesterfield and North Derbyshire Royal Hospital Damien Walmsley Professor of Restorative Dentistry, University of Birmingham School of Dentistry

Cover Picture: A Grey Seal pup playfully biting at the camera dome. Location - Farne Islands, UK. Highly Commended, British Wildlife Photography Awards 2019 (Courtesy of Nicholas More, Photographer, Exmouth Devon).

DentalUpdate

Don’t forget to renew your patient’s Duraphat prescription

76% of patients

prefer the taste of Duraphat 5000 ppm

#,1

Effective prevention for patients at increased caries risk* • 5000 ppm Fluoride Toothpaste prevents cavities by arresting and reversing primary root and early fissure caries lesions2-5 Prescribe Duraphat 5000 ppm Fluoride Toothpaste and support patient adherence: • 89% of consumers agree that taste is an important factor when using a toothpaste** • Prescribing a product with a preferred taste may be important to enhance patient adherence

1.1% Sodium Fluoride

Be confident prescribing Colgate Duraphat , the brand your patients know and trust† ®

®

# Compared to generic 5000 ppm high fluoride toothpaste. * Patients ≥ 16 years at increased caries risk. ** Colgate UK Consumer Survey on Cosmetic Toothpaste. 504 participants. Feb 2020. † YouGov Omnibus for Colgate® UK, data on file June 2015. Claim applies only to the Colgate® brand. References: 1. Data on file. Preference Survey. January 2020 (n=82). 2. Baysan A et al. Caries Res 2001;35:41-46. 3. Schirrmeister JF et al. Am J Dent 2007;20. 212-216. 4. Ekstrand et al. Geodent 2008;25:67-75. 5. Ekstrand et al. Caries Res 2013;47:391–8. Colgate® Duraphat® 5000 ppm Fluoride Toothpaste - Name of the medicinal product: Duraphat® 5000 ppm Fluoride Toothpaste. Active ingredient: Sodium Fluoride 1.1%w/w (5000ppm F-). 1g of toothpaste contains 5mg fluoride (as sodium fluoride), corresponding to 5000ppm fluoride. Indications: For the prevention of dental caries in adolescents and adults 16 years of age and over, particularly amongst patients at risk from multiple caries (coronal and/or root caries). Dosage and administration: Brush carefully on a daily basis applying a 2cm ribbon onto the toothbrush for each brushing. 3 times daily, after each meal. Contraindications: This medicinal product must not be used in cases of hypersensitivity to the active substance or to any of the excipients. Special warnings and precautions for use: An increased number of potential fluoride sources may lead to fluorosis. Before using fluoride medicines such as Duraphat, an assessment of overall fluoride intake (i.e. drinking water, fluoridated salt, other fluoride medicines - tablets, drops, gum or toothpaste) should be done. Fluoride tablets, drops, chewing gum, gels or varnishes and fluoridated water or salt should be avoided during use of Duraphat Toothpaste. When carrying out overall calculations of the recommended fluoride ion intake, which is 0.05mg/kg per day from all sources, not exceeding 1mg per day, allowance must be made for possible ingestion of toothpaste (each tube of Duraphat 500mg/100g Toothpaste contains 255mg of fluoride ions). This product contains Sodium Benzoate. Sodium Benzoate is a mild irritant to the skin, eyes and mucous membrane. Undesirable effects: Gastrointestinal disorders: Frequency not known (cannot be estimated from the available data): Burning oral sensation. Immune system disorders: Rare (≥1/10,000 to ViöVœ˜½Ãˆ˜wÌÀ>̈œ˜̅iÀ>«Þ“>ŽiÈ̫œÃÈLi° *ÀœÛi˜°œÀ>܈`iÀ>˜}iœvˆ˜`ˆV>̈œ˜Ã]vÀœ“V>Àˆœ}i˜ˆV܅ˆÌiëœÌà ̜y՜ÀœÃˆÃœÀVœœÕÀV…>˜}iÃV>ÕÃi`LÞÌÀ>Փ>° ˆÃVœÛiÀ̅i>ÌiÃÌ ܅ˆÌiëœÌÌÀi>̓i˜ÌvœÀޜÕÀÃiv>˜`ޜÕÀ«>̈i˜Ìð

712 DMGDentalUpdate Half Page.indd 1

October 2020 02/09/2020 16:13

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OralSurgery

Enhanced CPD DO C

Brandon Owen Graham Oliver, Lucy Macey-Dare and Gregor Knepil

Coronectomy: not just for Wisdom Teeth Abstract: Coronectomy is most commonly associated with the management of impacted lower third molars where complete removal poses a high risk of inferior alveolar nerve damage. However, coronectomy may be indicated for the management of other teeth with a significant risk of morbidity. A case of a LL6 extended coronectomy is presented. The aim was to prevent inferior alveolar nerve damage, and ensure adequate crown and root removal to facilitate orthodontic alignment of the teeth. Surgery was aided by cone beam CT, and a piezo-surgical technique. CPD/Clinical Relevance: This case demonstrates the novel application of a coronectomy to manage an infra-occluded lower left first molar, facilitating orthodontic treatment, where complete removal posed a high risk of inferior alveolar nerve damage. Dent Update 2020; 47: 714–718 Standard coronectomy is the technique where the crown of a tooth is sectioned and removed just below the amelo-cemental junction, leaving a substantial portion of roots in situ and untouched. It is frequently indicated for the management of impacted lower third molars, which carry a high risk of inferior alveolar nerve injury (IANI).1 IANI can cause altered sensation, such as numbness or pain to the lower lip and chin.2 This can have a profound effect on an individual’s ability to eat and speak, their social

Brandon Owen, BDS, MFDS, DCT1, Oral and Maxillofacial Surgery (email: [email protected]), Graham Oliver, BDS, DClinDent, MFDS, MOrth, Orthodontic Specialty Registrar, Lucy Macey-Dare, BDS, FDS RCS, FDS(Orth) RCS, MSc, MOrth RCS, Consultant Orthodontist and Gregor Knepil, BDS, MFDS, MBChB, MRCS, FRCS, Consultant Oral and Maxillofacial Surgeon, Gloucestershire Hospitals NHS Foundation Trust, Department of Oral and Maxillofacial Surgery, Gloucestershire Royal Hospital, Great Western Road, Gloucester GL1 3NN, UK.

714 DentalUpdate

interactions and, as a consequence, their quality of life.3,4 Case selection for coronectomy is important and should be limited to vital teeth with a high risk of IANI, in patients who are not immunocompromised and have good healing potential. Mobilization of roots at the time of surgery indicates need for extraction of the whole tooth, and is important for patients to understand during the consent process. Renton et al reported a 38% failure rate of coronectomy.5 Appropriate follow up, and ability to manage any complications such as infection, root migration and need for further surgery, is also important.6 Root migration is frequent following coronectomy. A 2015 systematic review reported an incidence of 2%−85.3%. Re-operation rates due to infection or migration varied from 0.6−6.8%. It was also reported that, if a second surgical procedure is indicated, safer surgery may be possible as the roots generally migrate away from the IAN.7 This is a case report of an ‘extended’ coronectomy of a mandibular first molar which was considered to pose a high risk of IANI. The aim of treatment

in this case was to prevent nerve damage, and also facilitate orthodontic alignment of the teeth by extending the degree of tooth structure removed.

Case report On examination

A 13-year-old female was referred to the orthodontic department by her General Dental Practitioner (GDP) regarding an unerupted LL6. The patient attended with her father, who was deaf, and so communication throughout was aided with the use of British Sign Language. The patient and parents were concerned about the appearance of her front teeth, as well as being aware of a ‘stuck’ tooth resulting in a gap between the teeth. The patient had well controlled asthma and was otherwise fit and well. She had a dental history of trauma to her UR2, and previously had restorative treatment under local anaesthetic. On examination, the patient had an Angle’s Class II division 1 malocclusion, on a Class II skeletal pattern with an increased lower anterior face height. The malocclusion was complicated by bimaxillary crowding, an unerupted LL6 and an uncomplicated crown fracture of October 2020

OralSurgery

enlarged follicle surrounding the LL6. The patient was diagnosed with an infra-occluded LL6, possibly due to a mechanical failure of eruption. Treatment options

Figure 1. OPT demonstrating the position of the unerupted inferiorly displaced LL6.

a

b

Figure 2. (a, b) CBCT demonstrating the position of the IAN in relation to the LL6.

October 2020

the UR2. In centric occlusion, the overjet was 6 mm with reduced overbite, and the molars were a half unit II on the right side. The oral hygiene was satisfactory and there were occlusal restorations in the UR6, LR6, UL6 and UL7. An Orthopantomogram (OPT) revealed an unerupted, inferiorly displaced LL6 with apices at the inferior border of the mandible; the adjacent LL7 was erupted and tipped mesially over the LL6 and in close proximity to the LL5. The roots of the LL7 showed an intimate relation to the LL6 crown, although there was no obvious evidence of root resorption (Figure 1). The inferior dental canal (IDC) was closely related to the roots of the LL6, with darkening of the mesial root, and interruption of the white lines of the IDC. The patient was seen on a multidisciplinary clinic, including a consultant orthodontist, and an oral surgeon. Due to the position of the LL6 and the risk factors relating to the IAN identified on the OPG, the patient was referred for a cone beam CT (CBCT) (Figure 2). The CBCT revealed that the four apices of the LL6 extended to the inferior cortex. The IAN was encircled by the apices of the LL6 with signs of notching of the mesio-lingual root. There was also suggestion of a slightly

Three management options were considered: 1. Monitoring; 2. Surgical removal of the entire tooth; and 3. ‘Extended’ coronectomy. Monitoring would involve periodic radiographic review to monitor any potential cystic change or root resorption; however, this would prevent alignment of the LL7. Alignment of the maxillary dentition would have been possible to an extent, but would not achieve a satisfactory result. Surgical extraction would allow alignment of the teeth after bony infill, but would carry a significant risk of damage to the IAN, and risk of mandible fracture. An extended coronectomy was felt by clinicians and patient to be the best option to minimize risk of IANI and enable the patient to pursue orthodontic treatment following bony infill. The concern was to ensure that sufficient space was created to upright the LL7. This was achieved using measurements taken from the CBCT to estimate the LL7 total tooth height against the height of the mandible and relative position of the LL6. This showed that the crown, and the roots beyond the furcation, had to be removed. Risks of the surgical procedure included requirement for extraction at time of surgery should mobilization of the roots occur, damage to the IAN, jaw fracture, or need for further surgery in future if the apices migrate away from the lower border. Surgery and follow-up

The procedure was undertaken as a day case, under general anaesthetic. A buccal sulcular incision was made and the mental nerve identified intact. Using a piezosaw, a buccal window of bone was removed to access the LL6. The crown of the LL6 was removed, as well as root tissue, to below the level of the DentalUpdate 715

OralSurgery

assault. Clinically, no pathology or signs of mandibular fracture were evident. An OPT excluded infection and fractures; however, it did demonstrate early infill of bone at the site of coronectomy (Figure 3b).

a

Discussion Consideration of coronectomy is almost synonymous with high risk mandibular third molars, but it is an important treatment option when any extraction poses a high risk of IANI. Previous case reports

b

Figure 3. (a) An OPT taken 6 weeks post coronectomy demonstrating the position of the two remaining roots of the LL6. (b) An OPT demonstrating early infill of bone at 5 months post-op.

furcation. Surgicel® (Ethicon) was placed and the surgical site closed with 4-0 Vicryl Rapide™ (Ethicon); a 5-day prophylactic course of co-amoxiclav was prescribed to help reduce risk of post-operative infection. The patient was advised to abstain from any contact sports for 6 weeks. The patient was reviewed clinically and radiographically 6 weeks later (Figure 3a); no altered sensation, pain or numbness was reported in the distribution of the IAN. The management plan was to review the patient in 6 months to assess the degree of bony infill at the surgical site and investigate the possibility of commencing orthodontic treatment. Five months post-surgery, the patient attended with pain in the lower left quadrant following an alleged

716 DentalUpdate

No high-quality evidence or formal guidance regarding coronectomy to manage non-third molar teeth exists. A report of two cases in which standard coronectomy was used to manage infraoccluded mandibular first permanent molars with close relationships to the IAN is available. However, the position of the remaining roots prevented orthodontic space closure.8 A further report is also available regarding the coronectomy of an infra-occluded LR5 and LR6, in which there was deemed to be a high risk of IANI with complete removal; the retained roots also allowed preservation of the alveolar ridge for a prosthesis.9 Coronectomy of an infra-occluded deciduous molar has even been reported.10 In all cases, coronectomy was performed as an alternative to complete removal for the primary reason of minimizing risk of IANI. The reported cases were successful as no IANI was reported. Risk assessment Radiographic assessment

Certain plain film radiographic signs are associated with a higher risk of IANI following third molar removal. This includes: diversion of the inferior dental canal, darkening of the root, interruption of the canal lamina dura, narrowing of the root/ canal and interruption of the juxta-apical area.6 In the presented case, darkening of the root, interruption of the canal lamina dura, and narrowing of the canal was visible. A CBCT was therefore justified to visualize the relationship of the tooth to the nerve. Cone beam computed tomography (CBCT)

CBCT is a highly useful diagnostic tool

for the determination of the relationship between teeth and the IAN. CBCT signs of increased risk of IANI includes:6 „ Loss of canal cortex >3 mm; „ Dumb-bell distortion of IDC; „ Lingual position of canal to roots; „ Perforation of roots by canal; „ Inter-radicular canal with multiple roots. CBCT enabled the authors to visualize the three-dimensional relationship of the tooth, IAN and surrounding structures to facilitate surgical planning. CBCT can occasionally prove that the tooth and nerve are not as intimate as indicated by plain film alone and avoid unnecessary coronectomy. If mobilization of roots at the time of coronectomy occurs, enhanced information may enable their removal with reduced morbidity. Furthermore, the information gained from the CBCT helped the patient and family to reach a more informed decision regarding her treatment. Patient selection

Following radiographic examination, the patient was deemed to be at a higher risk of IANI. Coronectomy was therefore considered as a management option. Standard coronectomy principles for lower third molars were used to guide suitability. In this case, coronectomy was deemed appropriate, as complete removal placed the patient at high risk of IANI, as well as being medically fit and well with good healing potential. The patient also demonstrated good compliance with the ability to attend multiple appointments. Furthermore, the tooth was absent of any significant pathology, such as caries in close proximity to the pulp or periapical pathology. Selvi et al reported that increasing age and females are more at risk of an IANI.11 This may influence the decisionmaking process for clinician and patient. Piezosurgery

Piezosurgery was used in this case, since it allows a high degree of surgical precision for the removal of hard tissues whilst helping to spare mechanical and thermal damage to soft tissues.12 Better wound healing and bone response have been observed in comparison to conventional rotary instruments.13 In this case, a need to October 2020

OralSurgery

preserve the IAN and viability of bone for infill was especially important to facilitate orthodontic treatment, and restore strength to the mandible. Even in cases of direct nerve contact with piezosurgical instruments, the injury is more favourable and has a better outcome in comparison to conventional instruments.14 Furthermore, the action of the vibrations and irrigant help to wash away debris, improve visibility and decrease heat generation.15 Multidisciplinary planning and orthodontic tooth movement

This case highlights the benefits of multidisciplinary planning between surgeon and orthodontist to facilitate the patient’s and clinician’s end goal of tooth alignment with minimum morbidity. A key consideration was the need to ensure that there was sufficient room for mesial apical movement of the LL7 after the coronectomy. Failure to appreciate the vertical space requirements would have resulted in a futile coronectomy, inability to upright the LL7, and potential root resorption. During orthodontic treatment, further radiographic reviews will be undertaken to check that the LL7 apices are clear of the retained roots and ensure that the apices have not migrated following surgery. The authors are confident that the orthodontic uprighting process of the LL7 should be successful and relatively quick, in part due to the effect of the regional acceleratory phenomenon (RAP). RAP describes the process by which noxious stimuli induce increased remodelling and healing of tissues, allowing for temporary accelerated tooth movement.16,17

materially significant treatment options to achieve informed consent. This case illustrates the role of extended coronectomy, assisted with CBCT and piezosurgery, to reduce the morbidity of orthodontic treatment in the developing dentition. Coronectomy is an important consideration where extraction involves a high risk of inferior alveolar nerve injury, and is assisted by CBCT, which can further stratify the level of risk and guide surgical planning. Patients must understand all future implications of this treatment approach. Early identification, management and appropriate referral are important steps in the management of complex problems in the developing dentition.

Conflict of Interest: The authors declare that they have no conflict of interest. Informed Consent: Informed consent was obtained from all individual participants included in the article.

Patients must be presented with all

718 DentalUpdate

9.

10.

11.

References 1.

2.

3.

Interception

Conclusion

8.

Compliance with Ethical Standards

4. Early identification and appropriate referral of problems in the developing dentition is an important role for GDPs. Early management can often help negate the need for complex invasive treatment. In this case, the patient was referred at age 13, around 7 years after the usual LL6 eruption date. It is possible that the position of the LL6 could have been improved with earlier management.

7.

5.

6.

O’Riordan BC. Coronectomy (intentional partial odontectomy of lower third molars). Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004; 98: 274−280. Renton T. Prevention of iatrogenic inferior alveolar nerve injuries in relation to dental procedures. Dent Update 2010; 37: 350−363. Ziccardi VG, Zuniga JR. Nerve injuries after third molar removal. Oral Maxillofac Surg Clin N Am 2007; 19: 105−115. Smith JG, Elias L-A, Yilmaz Z, Barker S, Shah K, Shah S et al. The psychosocial and affective burden of post traumatic neuropathy following injuries to the trigeminal nerve. J Orofac Pain 2013; 27: 293−303. Renton T, Hankins M, Sproate C, McGurk M. A randomised controlled clinical trial to compare the incidence of injury to the inferior alveolar nerve as a result of coronectomy and removal of mandibular third molars. Br J Oral Maxillofac Surg 2005; 43: 7−12. Renton T. Update on coronectomy. A safer way to remove high risk

12.

13.

14.

15.

16.

17.

mandibular third molars. Dent Update 2013; 40: 362−368. Martin A, Perinetti G, Costantinides F, Maglione M. Coronectomy as a surgical approach to impacted mandibular third molars: a systematic review. Head Face Med 2015; 11: 9. Chalmers E, Goodall C, Gardner A. Coronectomy for infraoccluded lower first permanent molars: a report of two cases. J Orthod 2012; 39: 117−121. Biocanin V, Todorović L. Coronectomy of two neighbouring ankylosed mandibular teeth − a case report. Vojnosanit Pregl 2014; 71: 777−779. Hussain MG, Sah SK, McHenry I. Case report: coronectomy of an impacted and submerged second deciduous molar. Br Dent J 2018; 224: 20−21. Selvi F, Dodson TB, Nattestad A, Robertson K, Tolstunov L. Factors that are associated with injury to the inferior alveolar nerve in high-risk patients after removal of third molars. Br J Oral Maxillofac Surg 2013; 51: 868−873. Pavlíková G, Foltán R, Horká M, Hanzelka T, Borunská H, Šedý J. Piezosurgery in oral and maxillofacial surgery. Int J Oral Maxillofac Surg 2011; 40: 451−457. Vercellotti T, Nevins ML, Kim DM, Nevins M, Wada K, Schenk RK, Fiorellini JP. Osseous response following resective therapy with piezosurgery. Int J Periodontics Restorative Dent 2005; 25: 543−549. Schaeren S, Jaquiéry C, Heberer M, Tolnay M, Vercellotti T, Martin I. Assessment of nerve damage using a novel ultrasonic device for bone cutting. J Oral Maxillofac Surg 2008; 66: 593−596. Schlee M, Steigmann M, Bratu E, Garg AK. Piezosurgery: basics and possibilities. Impl Dent 2006; 15: 334−337. Frost HM. The regional acceleratory phenomenon: a review. Henry Ford Hosp Med J 1983; 31: 3−9. Kim SJ, Park YG, Kang SG. Effects of Corticision on paradental remodeling in orthodontic tooth movement. Angle Orthod 2009; 79: 284−291. October 2020

RestorativeDentistry

Enhanced CPD DO C

Ronan B O'Leary Anne L Gunderman

A Combined Digital-Conventional Workflow to Fabricate a Removable Partial Denture for a Patient with a Severe Gag Reflex Abstract: Introducing a novel approach to overcoming a profound gag reflex and aversion to conventional dental impression procedures when fabricating a removable partial denture. The digital workflow is becoming increasingly popular in the discipline of fixed prosthodontics. Chairside digitization of a patient’s dentition is a less invasive and more comfortable procedure in comparison to conventional dental impression techniques. The advantages can be most relevant to patients with a profound gag-reflex. Currently, certain challenges exist with full digitization in the discipline of removable prosthodontics. Combining digital and conventional workflows may serve as an alternative technique to construct removable prostheses for groups who cannot tolerate conventional methods. CPD/Clinical Relevance: Many patient groups may not tolerate conventional dental impression techniques. This method offers a combination of existing techniques as a suitable alternative for this cohort. Dent Update 2020; 47: 719–727 The digital workflow is established now as a clinically acceptable method of fabricating single unit crowns or short-span fixed partial dentures (FPDs), both on natural Ronan B O’Leary, BA, BDentSc, Dip PCD, MFD(RCSI), MAcadMEd, Senior House Officer in Restorative Dentistry, Division of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, Lincoln Place, Dublin 2 D02 F859 (email: olearyrb@ tcd.ie), and Anne L Gunderman, BS, DDS, MS, Diplomate of the American Board of Prosthodontics, Senior Lecturer Graduate Prosthodontics, Trinity College Dublin/Dublin Dental University Hospital; Private Practice Limited to Prosthodontics, Fitzwilliam Square, Dublin 2, D02 CY65, Ireland. October 2020

teeth1-6 as well as dental implants,7,8 in the discipline of fixed prosthodontics. One of the main advantages of this workflow is from the perspective of patient comfort. Direct chairside digitization of a patient’s dentition is a less invasive and more comfortable procedure in comparison to conventional dental impression techniques using either irreversible hydrocolloids or elastomeric impression materials. The literature suggests that this patient comfort factor is most relevant in patients who experience a profound gag reflex.9 However, currently, direct chairside digitization is considered to be less predictable for the fabrication of crossarch frameworks,10-13 such as those that might be fabricated in the discipline of removable prosthodontics. This is because of the effect of error accumulation that occurs during the stitching of multiple

three-dimensional (3D) images over a broad surface area during the chairside digital impression procedure. The literature suggests that such error accumulation can reach clinically relevant levels of inaccuracy in full-arch digital dental impressions.10-14 Furthermore, when fabricating removable partial dentures (RPDs), practical issues can arise when attempting to process polymethylmethacrylate (PMMA) to partial denture frameworks, if milled or 3D printed resin mastercasts are used. This case report discusses a novel approach, combining the digital and conventional workflows, to fabricate a metal-ceramic FPD, single crown and cobalt-chromium framed RPD for a patient with a particularly severe gag reflex, within the context of a staged treatment plan. This case report will discuss how procedural difficulties were overcome by DentalUpdate 719

RestorativeDentistry

a

a

procedures in the past. In spite of these difficulties, the patient was determined to seek a treatment solution which would enable her in wearing a partial denture in recognition of the necessity of posterior teeth in protecting the remaining anterior dentition.15 More complex treatment options, involving fixed rehabilitation with dental implants and bone augmentation, were rejected by the patient, and the combined fixed and removable partial denture treatment option was accepted as her preferred option. The aims of treatment were to restore the maxillary labial segment with a 3-unit FPD and single unit crown and then to restore the posterior dentition with an RPD, using a staged approach to overcome the profound gag reflex and assess the patient’s tolerance of a maxillary partial denture.

b b

c c

Figure 1. (a) Retracted frontal view (preoperative) showing existing provisional FPD and deep vertical overlap. (b) Maxillary occlusal view (pre-operative) showing Kennedy II mod II arch. Note the UR2 is an edentulous space with a provisional FPD. The maxillary incisors are retroclined. (c) Mandibular occlusal view (preoperative). The mandible is a Kennedy I arch with severely atrophied posterior ridge form.

switching between digital and conventional techniques at relevant stages during these clinical procedures.

Case report The patient is a 61-year-old female with no relevant medical history who presented to the senior house officer restorative clinic seeking a fixed prosthodontic replacement for her recently extracted upper right lateral incisor tooth. She was also troubled by her lack of posterior teeth, both from an aesthetic as well as a functional perspective. The upper right lateral incisor tooth was lost to a non-restorable crown-root fracture 6 months prior to presentation. A provisional, PMMA FPD had been fabricated to restore this site prior to referral to the senior house officer restorative clinic. On intra-oral examination, a Class II division 2 incisor

720 DentalUpdate

Figure 2. (a) Definitive tooth preparations. Note the soft tissue health from wearing a well-adapted provisional, supragingival finish lines and the patient demonstrating good oral hygiene. The soft-tissue contour of the UR2 site has also been adapted by the provisional FPD. (b) Virtual mastercast of the definitive tooth preparations. (c) Virtual mastercast of the definitive tooth preparations (occlusal view). Note the reductions for a metal-ceramic restoration, with additional reduction in the cingulum area to account for rest-seats incorporated into the metal palatal surfaces of the restorations.

relationship, complicated by deep vertical overlap and a lack of posterior support, was noted. The maxilla was a Kennedy II mod II arch, whilst the mandible was a Kennedy I arch with severely atrophied posterior ridge form. The periodontal status was stable, oral hygiene was fair, however, there was no evidence of periodontal pocketing beyond 2 mm and there was no evidence of bleeding on probing. (Figure 1a−c). On presentation to the operator, the patient reported profound difficulty with the severity of her gag reflex during dental procedures, particularly impressiontaking procedures with conventional elastomeric impression materials. The gag reflex was so strong that several episodes of vomiting had occurred during dental

Clinical and laboratory procedures Tooth preparations in the maxillary labial segment were refined in order to achieve adequate retention and resistance form with supragingival margin placement (Figure 2a), and a virtual mastercast was fabricated by chairside digitization using a 3Shape Trios® (3Shape, Copenhagen, Denmark) intra-oral scanner (Figure 2b and c). At the dental laboratory, uniformly cut-back copings were prepared by computer-aided-design (Figure 3a and b) and were machine fabricated in cobaltchromium using the selective laser melting (SLM) additive manufacturing technique (Figure 3c and d). The crown and FPD were surveyed and incorporated cingulum rest seats and a guide-plane on the distal surface of the UR3. A metal try-in was carried out to verify the fit and occlusal relationship of the copings (Figure 4a and b), following which aluminous porcelain was hand-stacked at the dental laboratory (Figure 5a and b). The definitive metalceramic units were cemented with glass ionomer cement (Ketac™ Cem, 3M ESPE, Minnesota, USA). With no improvement in the patient’s profound gag reflex, a novel approach was used for fabrication of the cobalt-chromium framed RPD, whilst avoiding slow-setting conventional elastomeric impression procedures. The October 2020

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RestorativeDentistry

a

a

a

b b

b Figure 4. (a) Metal copings tried in the mouth to verify fit and occlusion. (b) Occlusal view showing occlusal contacts and adjustments.

c

a

d

Figure 6. (a) CAD RPD framework on the virtual mastercast. (b) RPD framework on the 3D printed resin model.

b

Figure 3. (a) CAD metal copings (on virtual mastercast) for the crown UL1 and 3-unit FPD UR1–UR3. (b) Uniformly cut-back CAD metal copings (on virtual mastercast). Occlusal view shows the cingulum rests incorporated into the metal and guide-plane on the distal of the UR3. (c) Metal copings on the 3D printed resin mastercast. (d) Occlusal view. Note how the metal is not polished at this stage. It allows for adjustment prior to sending it back to the lab for addition of the ceramic and polishing.

maxillary denture-bearing area, including the dentition and mucosa, was recorded by chairside digitization using a 3Shape Trios® intra-oral scanner. From this intraoral scan, a partial denture framework was prepared by CAD (Figure 6a) and, again, was machine-fabricated in cobalt-chromium by SLM (Figure 6b). The cobalt-chromium

722 DentalUpdate

Figure 5. (a) The finished metal-ceramic crown and FPD returned from the laboratory. (b) The finished metal-ceramic crown and FPD returned from the laboratory. The palatal surface is in metal and includes the cingulum rest seats and the guide-plane on the distal of UR3.

partial denture framework was tried in the patient’s mouth. Several cycles of fit-check adjustments were required to permit full and accurate seating of the framework until a clinically acceptable framework fit was achieved by this method. The patient tolerated the full seating of the framework well, with limited exacerbation of her gag reflex. In order to capture the

mucosal aspect of the denture-bearing area accurately, a conventional functional impression was made in zinc oxide eugenol (Kelly’s® Z.O.E. Impression Paste, Waterpik, Colorado, USA) using a custom tray attached to the partial denture framework (Figure 7a and b). At this point, it was necessary to fabricate a conventional gypsum model of the maxilla to permit heat processing of PMMA to the partial denture framework. As such, the framework, complete with custom impression of the denture-bearing mucosa, was picked up into a fast-setting alginate impression, and poured immediately to form a conventional denture mastercast. Denture teeth and PMMA were heat-processed to the cobaltchromium framework using the flask, pack and press technique (Figure 8a, b and c). The RPD was definitively fitted and the patient has adapted well to her new prosthesis (Figure 9a, b and c). Given that this combined digital and conventional workflow has been successful in fabricating the maxillary removable prosthesis, and October 2020

RestorativeDentistry

a

a

a

b b b

c

Figure 7. (a) Border moulding and functional impression made using the metal framework. (b) Functional impression for the region of the distal extension in the right posterior maxilla.

given the adaptation of the patient to this removable prosthesis in the context of her gag reflex, the next stage of the treatment plan is to begin fabrication of a mandibular RPD using a similar workflow.

Discussion

c Figure 9. (a) The final fixed and removal prostheses in situ (Smile). The clasp at UR3 and the gingival margins are not normally visible. (b) Anterior view. (c) Maxillary occlusal view. Figure 8. (a) The processed denture (occlusal view) showing the palatal ring major connector to minimize material on the palate. (b) The processed acrylic in the right buccal flange showing good adaptation/contour after using this method. (c) The advantages of using a cobalt-chromium framework allowed minimal thickness of material on the palate.

Patient groups

Conventional elastomeric impression materials take several minutes to set in the mouth. This can be a very long, unpleasant and, in rare instances, dangerous experience for patients. Groups affected include those with a profound gag-reflex, but also patients with learning impairments, patients with temporomandibular joint disorders, children, and those who are at risk of aspiration. Bateman and Saha16 reported a case of a 72-year-old man following aspiration of dental impression material. The patient required hospitalization and passed away 33 days later in respiratory arrest. They also identified three other cases in the literature reporting aspiration of impression material.17-19 For patients with dysphagia, reducing reliance on flowable impression materials in the mouth may October 2020

reduce aspiration risk for those susceptible. By using intra-oral scanners, the use of traditional materials can be reduced. In this regard, without physical material in contact with the oral and pharyngeal tissues, the potential for gag-reflex activation may be reduced. This should be true if the reason for gagging was caused by a physical stimulus and not a mental trigger. Dickinson and Fiske developed a classification in 2005, including the causes of gagging. They included a ‘Gagging Prevention Index’, which was graded by the level of treatment that was possible to carry out, taking into account the severity of gagging experienced.20,21 The use of intraoral scanners have the potential to reduce

the severity on this scale, without changing to a compromised alternative treatment plan. For patients with temporomandibular joint disorders, this method allows for breaks in the scan process in an effort to reduce symptoms of fatigue on wide mouth opening.

Challenges with chairside digitization Chairside digitization presents challenges when trying to obtain highly accurate crossarch dental prostheses.22 Error accumulation that occurs during the stitching of multiple 3D images over a broad surface area across the arch can lead to clinically relevant levels of inaccuracy. A second cause of error in digital acquisition of the dentition is the occlusal relationship in both static and dynamic relations. This is compounded by partially dentate patients that fall into the Kennedy Class I and II categories. This case required model generation and accurate interocclusal record techniques DentalUpdate 723

RestorativeDentistry

involving a semi-adjustable articulator. The complexities of this case required both accurate articulator mounting, and accurate dynamic lateral and protrusive replication, to ensure that the restorations conformed to the patient’s existing occlusal parameters, and canine and protrusive guidance were controlled. A re-organized occlusal approach can present with even more profound challenges for a purely digital workflow.22 Cobalt-chromium frameworks for RPDs previously had high financial and time costs due to the casting of the metal alloys. It is likely, as these alternative methods become more established, manufacturing time and costs will reduce. The initial setting-up costs for the chairside digital equipment is a potential barrier to some practitioners at this time. Removable partial dentures with distal extensions should incorporate maximum functional extension of the denture-bearing area. Intra-oral scanners do not operate in the same way that impression materials do to achieve this, such as border moulding to achieve a functional impression. The intra-oral scanner will only capture a snapshot of the tissues in their retracted state, which is not truly based on functional movements. The argument can also be made that scanners lack the muco-compressive properties of impression material. The clinical impact of this is not fully understood at this moment in time. Lastly, in a digital workflow when adding acrylic to the metal framework, the options are limited. As no mastercast is required for the SLM method of framework fabrication, one is only supplied if requested, and this comes in the form of a 3D printed resin model fabricated from the scan. The resin model prohibits the use of heat-cured PMMA as the technique of flask, pack and press is not compatible with this. The resin model cannot be destroyed to retrieve the processed denture as predictably as a stone model can be. Currently, in fully digital workflows, cold-cure alternatives are used which can have compromised material properties compared to

724 DentalUpdate

pressure-moulded, heat-activated resins, such as reduced transverse strength and increased porosity.23 The described method in this report suggests an alternative way to simply convert to conventional techniques at a relevant stage to take advantage of the benefits of heat-cured PMMA.

was obtained from all individual participants included in the article.

References 1.

Conclusion Although patients with a profound gag reflex may initially reject a removable prosthesis, a carefully designed cobaltchromium RPD may be a suitable option, as it was in this case. By using a surveyed crown and FPD, it maximized the success of the removable prosthesis. This permitted the patient to still have a restored UR2 should she not have tolerated the RPD. Other natural tooth preparations were minimal and the intra-oral scans were not invasive or traumatizing to the patient. The necessary conventional techniques were more easily controlled by the use of customized trays and control of material setting properties by temperature and technique manipulation. As can be seen in Figure 8, the metal was thin and streamlined and the palatal ring major connector minimized the chances of activating the gag-reflex. Try-in stage of the framework is likely to be a good indicator, if the patient will tolerate the prosthesis. In summary, cobaltchromium RPDs may be one option to be considered in a partially dentate patient with a history of a gag reflex if the prosthesis is designed well, the patient is willing, and an appropriate technique is used.

2.

3.

4.

5.

6.

Acknowledgements

The authors would like to thank Mr Dan Mulcare and Mr Ken Hall for the laboratory work and Dr David McReynolds for his guidance in writing this. This was a finalist case for the Gary Pollock prize at the BSRD Autumn Scientific Meeting 2018

7.

Compliance with Ethical Standards

Conflict of Interest: The authors declare that they have no conflict of interest. Informed Consent: Informed consent

8.

Anadioti E, Aquilino S, Gratton D, Holloway J, Denry I, Thomas G et al. 3D and 2D marginal fit of pressed and CAD/CAM lithium disilicate crowns made from digital and conventional impressions. J Prosthodont 2014; 23: 610−617. Seelbach P, Brueckel C, Wöstmann B. Accuracy of digital and conventional impression techniques and workflow. Clin Oral Invest 2012; 17: 1759−1764. Zarauz C, Valverde A, MartinezRus F, Hassan B, Pradies G. Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions. Clin Oral Invest 2015; 20: 799−806. Syrek A, Reich G, Ranftl D, Klein C, Cerny B, Brodesser J. Clinical evaluation of all-ceramic crowns fabricated from intraoral digital impressions based on the principle of active wavefront sampling. J Dent 2010; 38: 553−559. Abdel-Azim T, Rogers K, Elathamna E, Zandinejad A, Metz M, Morton D. Comparison of the marginal fit of lithium disilicate crowns fabricated with CAD/CAM technology by using conventional impressions and two intraoral digital scanners. J Prosthet Dent 2015; 114: 554−559. Almeida e Silva J, Erdelt K, Edelhoff D, Araújo É, Stimmelmayr M, Vieira L et al. Marginal and internal fit of four-unit zirconia fixed dental prostheses based on digital and conventional impression techniques. Clin Oral Invest 2013; 18: 515−523. Abdel-Azim T, Zandinejad A, Elathamna E, Lin W, Morton D. The influence of digital fabrication options on the accuracy of dental implant–based single units and complete-arch frameworks. Int J Oral Maxillofac Implants 2014; 29: 1281−1288. Lee S, Betensky R, Gianneschi G, Gallucci G. Accuracy of digital October 2020

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RestorativeDentistry

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10.

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versus conventional implant impressions. Clin Oral Implants Res 2014; 26: 715−719. Ahlholm P, Sipilä K, Vallittu P, Jakonen M, Kotiranta U. Digital versus conventional impressions in fixed prosthodontics: a review. J Prosthodont 2016; 27: 35−41. Ender A, Mehl A. Accuracy of complete-arch dental impressions: a new method of measuring trueness and precision. J Prosthet Dent 2013; 109: 121−128. Ender A, Mehl A. In-vitro evaluation of the accuracy of conventional and digital methods of obtaining full-arch dental impressions. Quintessence Int 2015; 46: 9−17. Güth J, Edelhoff D, Schweiger J, Keul C. A new method for the evaluation of the accuracy of full-arch digital impressions in vitro. Clin Oral Invest 2015; 20: 1487−1494. Kuhr F, Schmidt A, Rehmann P,

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Wöstmann B. A new method for assessing the accuracy of full arch impressions in patients. J Dent 2016; 55: 68−74. Nedelcu R, Olsson P, Nyström I, Rydén J, Thor A. Accuracy and precision of 3 intraoral scanners and accuracy of conventional impressions: a novel in vivo analysis method. J Dent 2018; 69: 110−118. Wiens J, Priebe J. Occlusal stability. Dent Clin N Am 2014; 58: 19−43. Bateman G, Saha S. Aspiration of dental impression material − a case report. Dent Update 2017; 44: 986−987. Cameron S, Whitlock W, Tabor M. Foreign body aspiration in dentistry: a review. J Am Dent Assoc 1996; 127: 1224−1229. Erren JP, Schipmann R. [Right-sided recurrent retention pneumonia of changing localization after aspiration of dental impression material

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with almost complete casting of a segmental bronchus in a previously healthy woman]. Pneumologie 1995; 49: 601−603. Sopena B, Garcia-Caballero L, Diz P, De la Fuente J, Fernandez A, Diaz JA. Unsuspected foreign body aspiration. Quintessence Int 2003; 34: 779−781. Dickinson C, Fiske J. A review of gagging problems in dentistry: 1. Aetiology and classification. Dent Update 2005; 32: 26−32. Dickinson C, Fiske J. A review of gagging problems in dentistry: 2. Clinical assessment and management. Dent Update 2005; 32: 74−80. McReynolds D, O’Sullivan M. Pushing the envelope of digital dentistry. J Ir Dent 2019; 65: 333−338. Anusavice K, Shen C, Rawls R. Phillips’ Science of Dental Materials. 12th edn. St. Louis: Elsevier Saunders, 2012.

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GeneralDentistry/PaediatricDentistry/Orthodontics

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Maurice J Meade

Supernumerary Teeth: an Overview for the General Dental Practitioner Abstract: Supernumerary teeth can develop in any location of the mandible or maxilla and may have a significant impact on the developing dentition. This paper reviews the prevalence, aetiology and classification of supernumerary teeth. It also describes their clinical characteristics and management options. A case report involving the interdisciplinary management of delayed eruption of central incisors due to the presence of a supernumerary tooth is outlined. CPD/Clinical Relevance: Timely diagnosis and appropriate management may reduce the potential problems associated with supernumerary teeth. General dental practitioners should be aware of the clinical characteristics and management options related to supernumerary teeth. Dent Update 2020; 47: 729–738

A supernumerary tooth is one that has developed in addition to the normal complement of teeth within the dentition.1,2 Supernumerary teeth can occur in isolation or, less commonly, in association with a number of developmental medical disorders.3 They may be single or multiple, unilateral or bilateral, and can occur in the maxilla and/or mandible.1,2,4 Supernumerary teeth are thought to occur in the maxilla up to 10 times more frequently than the 2 mandible. The most common location involving one or two supernumerary teeth only is the premaxilla followed by the mandibular premolar region. The mandibular premolar region, however, appears to be the site in which multiple supernumerary teeth are most frequently located.4 Maurice J Meade, BDS, MDPH, MFDS RCS(Edin), MJDF RCS(Eng), DClinDent(Ortho), MOrth RCS(Edin), Orthodontic Unit, The School of Dentistry, The University of Adelaide, South Australia, Australia, (email: [email protected]). October 2020

Supernumerary teeth can cause problems during development of the dentition and may require removal and interdisciplinary management in some situations. The aims of this paper are to: „ Review the prevalence, aetiology and classification of supernumerary teeth; and „ Describe their clinical characteristics and management options. In addition, a case report involving the interdisciplinary management of delayed eruption of two maxillary central incisors due to the presence of a supernumerary tooth is outlined.

Prevalence The prevalence of supernumerary teeth in the primary dentition ranges from 0.3 to 0.8%, and in the permanent dentition from 1.2 to 3.5%.4 Supernumeraries in the primary dentition, however, may be underreported. As spacing is commonly present in the primary dentition, supernumerary teeth may erupt into reasonable alignment and remain

undetected at, or exfoliate prior to, initial dental inspection.1 Males appear to be more likely than females to present with a supernumerary in the permanent dentition.4,5 Ratios from 1.3:1 to 2.64:1 have been reported.6,7 The broad range of ratios may be due to the wide variety of methodologies adopted in assessing supernumerary teeth and may reflect the varying age ranges and populations assessed.7 Sexual dimorphism does not appear to be present in the primary dentition.1 Those who present with a supernumerary in the primary dentition, however, may demonstrate a higher prevalence of supernumerary teeth in the permanent dentition.8 The majority of patients present with one or two supernumerary teeth.9 Although multiple supernumerary teeth can occur in isolation (Figure 1), they are more commonly seen in patients with an associated syndrome or medical disorder (Table 1).3,10 In rare cases, the presence of multiple supernumerary teeth may be an important indicator of an undiagnosed medical disorder.11 DentalUpdate 729

GeneralDentistry/PaediatricDentistry/Orthodontics

Cleft lip and/or palate Classical Ehlers-Danlos syndrome Cleidocranial dysplasia Ellis-Van Creveld syndrome Familial adenomatous polyposis/ Gardner’s syndrome Fabry disease Hypermobile Ehlers-Danlos syndrome Incontinentia Pigmenti Kreiborg-Pakistan syndrome Nance-Horan syndrome Neurofibromatosis Type 1 Opitz GBBB syndrome

Figure 1. A dental pantomagram indicating 3 supernumerary teeth in the mandibular premolar regions and 1 supernumerary impeding eruption of the maxillary right second molar.

Papillon-League syndrome Robinow syndrome [Dominant form] Rubinstein-Taybi syndrome [RSTS1] Trichorhinophalangeal syndrome Table 1. Medical disorders associated with supernumerary teeth.

The syndromes and medical disorders most frequently associated with supernumerary teeth are cleft lip and palate (CLP), cleidocranial dysplasia (CCD) and familial adenomatous polyposis.3,6 The prevalence of supernumeraries in patients with CLP is reportedly between 1.9 and 10% and they are thought to be a result of disruption of the dental lamina during cleft formation.6,12 They are the second most common anomaly found in the cleft area.12 Patients with a history of anterior conical or tuberculate supernumerary teeth at an early age have a one-in-four chance of later developing single or multiple supernumerary premolars.7 CCD is a rare autosomal dominant developmental disorder. Associated characteristics include persistent open cranial sutures, hypoplasia/aplasia of the clavicles and

730 DentalUpdate

dental anomalies including multiple unerupted supernumerary teeth.13 A recent review, however, has suggested that some disorders where few individuals display the presence of supernumerary teeth could be coincidental rather than a true association.3

Aetiology The aetiology of supernumerary teeth is not fully understood.1,6,14 Environmental and genetic factors have been implicated. Three main theories have been proposed:2,4,7,15 1. Atavistic theory: Suggests that supernumerary teeth were the result of phylogenetic reversion to extinct primates with three pairs of incisors. 2. Dichotomy theory: Suggests that the tooth bud splits into two equal or different-sized parts, resulting in the formation of two teeth − one normal and one dysmorphic. 3. Dental lamina hyperactivity theory: Involves localized and independent, conditioned hyperactivity of the dental lamina. A supplemental form develops from the lingual extension of an accessory tooth bud, while the more rudimentary forms develop from proliferation of the epithelial remnants

of the dental lamina. The available evidence appears to support the dental lamina hyperactivity theory and discount 8the Atavistic and Dichotomy Theories. Current thinking indicates a genetic or, more likely, a multifactorial basis to supernumerary development.1,5,6 A genetic basis is suggested as supernumeraries appear to: „ Run in families: Studies have shown that children of parents with supernumerary teeth have an increased risk of their development;16 „ Display sexual dimorphism: A sexlinked transmission may explain the greater prevalence of supernumerary teeth in males;17 „ Demonstrate ethnic variation: Prevalence, for example, has been reported to be greater among AfricanAmericans;18 „ Be associated with some medical disorders and syndromes;3,4 „ Be associated with other dental anomalies: Patients with supernumerary teeth may have larger ‘normal’ teeth compared with those who have no supernumerary teeth, particularly in the mesio-distal dimension.19,20 In addition, there appears to be a significant association between supernumerary teeth and invaginated teeth.7,21 October 2020

GeneralDentistry/PaediatricDentistry/Orthodontics

Type of Supernumerary

Frequency (%)

Common Locations

Typical Clinical Appearance

Conical

75

Anterior maxilla (commonly between central incisors)

„ Small „ Triangular/conical/peg-shaped crown „ Normal root development „ May be inverted „ Usually erupts palatally, rarely labially „ Usually isolated

Tuberculate

12

Anterior maxilla

„ Barrel-shaped with multiple tubercles „ Deviant or absent root development „ Rarely erupts „ Commonly prevents eruption of central incisor „ Frequently in pairs „ Late forming

Supplemental

7

Any location (most commonly a permanent maxillary lateral incisor)

„ ‘Normal’ tooth appearance „ Last in series „ Usually erupts

Odontome

6

Anterior maxilla (compound) and posterior mandible (complex)

„ Calcified dental tissues that are either: - Compound: discrete structures similar to fully developed teeth; or - Complex: poorly organized tissues with minimal similarity to normal tooth „ Radiographically: mixed radio-opaque area surrounded by radiolucent band

Table 2. Supernumerary teeth classified according to morphology.

Type of Supernumerary

Characteristics

Mesiodens

„ Conical or triangular crown „ Small and short „ Located between the maxillary central incisors „ Usually palatal to the incisors „ Sometimes lying in the line of the arch or labially

Paramolar

„ Supernumerary molar „ Usually rudimentary „ Located buccally or lingually/palatally to one of the molars or interproximally buccal to the second and third molar

Distomolar

„ Located distal to the third molar „ Usually rudimentary „ Rarely delays the eruption of associated teeth

Parapremolar

„ Forms in the premolar region and resembles a premolar

Table 3. Supernumerary teeth classified according to location.

Investigations into tooth development in the mouse have also demonstrated a genetic premise for supernumerary tooth formation. Although a genetic element is the component most closely associated with supernumerary teeth, transcription factors and separate October 2020

molecular signalling pathways are likely to play a part too.6,22 For example, it has been shown that inappropriate regulation by the RUNX2 gene (involving the transcription factor CBFA1) of the activity of the signalling molecule called Sonic Hedgehog (Shh)

may be involved in the formation of supernumerary teeth in individuals with CCD.1,22

Classification of supernumerary teeth Supernumerary teeth are usually DentalUpdate 731

GeneralDentistry/PaediatricDentistry/Orthodontics

a

b

c Figure 4. DPT indicating a supplemental maxillary central incisor.

Figure 2. (a) Supplemental upper left lateral incisor (frontal view). (b) Supplemental upper lateral incisor (side view). (c) Supplemental upper lateral incisor (occlusal view).

teeth are described as dysmorphic.23 Supplemental types (Figures 2−4) are most likely to erupt, followed by conical and tuberculate.6 Figure 5 shows an upper right unerupted distomolar. Although odontomas and supernumeraries have been classified as separate entities, they appear to be the manifestation of the same odontogenic hyper-productive process from an etiopathogenetic and a clinical perspective.24 As a result, odontomas are commonly classified as a morphological supernumerary variant.

Displacement or rotation of permanent teeth

Clinical characteristics of supernumerary teeth

A previously undiagnosed or a late developing supernumerary may prevent space closure during orthodontic treatment.23,28

A supernumerary tooth may just be a ‘chance’ discovery on a radiograph and have no effect on the dentition.7,23 In many instances, however, a variety of effects can be seen and may be the first indication of the presence of a supernumerary. Figure 3. Supplemental lower right lateral incisor (occlusal view).

classified according to morphology (Table 2) or location (Table 3). A supernumerary tooth that has a similar morphology to a ‘normal’ tooth is described as eumorphic, whereas supernumeraries that bear little resemblance to ‘normal’

732 DentalUpdate

Delayed or prevention of eruption of permanent teeth

The most common complication from a supernumerary tooth is failure of eruption of a permanent maxillary incisor.9,25 Delayed eruption of associated teeth has been reported to occur in up to 60% of Caucasians with supernumerary teeth.26 Figure 1 shows a supernumerary tooth impeding the eruption of an upper right second permanent molar tooth.

A supernumerary tooth located between the roots of adjacent teeth may obstruct root approximation, resulting in a diastema. Displacement may vary from a mild rotation to complete displacement.7,9 Crowding

Erupted supplemental teeth most often cause crowding, although eruption of any supernumerary type can result in crowding (Figure 2).9,27 Incomplete space closure during orthodontic treatment

Pathology

Dentigerous cyst formation is a complication that may be associated with a supernumerary tooth.29 Root resorption, dilaceration and abnormal root development of associated permanent teeth have been reported to occur in association with supernumerary teeth, but all are rare occurrences.7,30 Additional manifestations

Migration of the supernumerary into the nasal cavity and hard palate has been reported in the literature but is very uncommon.31,32 October 2020

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Protecting your lifestyle. Securing your future. To find out more visit our website at www.dentistsprovident.co.uk / www.dentistsprovident.ie or call our member services consultants on 020 7400 5710 Dentists’ Provident is the trading name of Dentists’ Provident Society Limited which is incorporated in the United Kingdom under the Friendly Societies Act 1992 (Registration Number 407F). Authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the Prudential Regulation Authority in the United Kingdom (Firm Reference Number 110015) and regulated in the Republic of Ireland by the Central Bank of Ireland for conduct of business rules (Firm Reference Number C33946). Calls are recorded for our mutual security, training and monitoring purposes. These case studies are for illustration purposes only and not based on real individuals. They are not designed to provide financial advice, nor are they intended to make any recommendations regarding the suitability of our plans for a particular individual.

GeneralDentistry/PaediatricDentistry/Orthodontics

a

b

c Figure 5. Sectional DPT showing an upper right unerupted distomolar.

Figure 6. (a) DPT indicating a supernumerary tooth impeding the eruption of maxillary central incisors. (b) CBCT image of the supernumerary observed in (a). (c) CBCT image of the supernumerary tooth observed in (a).

Management Careful clinical and radiographic examination is essential to identify and localize supernumerary teeth.6 Management is dependent on supernumerary type and position and its effect or potential effect on the dentition, and should be the result of a risk-benefit assessment.33 It may be prudent to liaise with an orthodontist and/or an oral surgeon, particularly as management should be undertaken in conjunction with the correction of any underlying malocclusion.1,14,34 A dental pantomogram (DPT), an upper standard occlusal and/ or a long-cone periapical radiograph may be used in combination to localize a supernumerary tooth via the parallax technique.35 A lateral radiograph of the incisor region may assist in its location.9 Cone beam computed tomography (CBCT) may be required to localize its position more accurately and can facilitate more precise assessment of resorption in adjacent roots.36-39 In many situations, no October 2020

intervention is necessary. If there is considerable risk of damage to the roots of teeth adjacent to the supernumerary, or its position is unlikely to obstruct tooth movement in prospective orthodontic treatment, then removal may not be indicated.40 Early identification and treatment of supernumerary teeth is often advised to minimize complications. If the supernumerary is located close to developing roots, however, delaying removal until root development is complete may be recommended.41 This is to minimize the risk of irreversible damage to developing roots. Where further dental development is anticipated or a decision made not to remove a supernumerary, regular monitoring of the patient with relevant radiographic investigation at intervals agreed between the patient and his/her general dental practitioner (GDP) and/ or other oral healthcare providers is recommended.37,38 Removal is indicated if the supernumerary:

„ Interferes with normal dental development; „ Impedes planned orthodontic tooth movement; „ Has associated pathology; „ Compromises potential alveolar bone grafting sites in patients with cleft lip and palate; „ Is situated at a potential implant site.9,14,23 Removal of a supplemental supernumerary tooth is commonly indicated due to crowding, displacement of adjacent teeth and challenges associated with orthodontic inter-arch correction, if it is retained. Timely extraction of a supplemental lateral incisor, for example, may result in self-correction and satisfactory alignment.15 In this situation, the choice of tooth for extraction is based on: „ Crown and root size and morphology; „ Degree of displacement; „ Ease of surgical access; and „ Periodontal considerations.

Case Report Figures 6 a−c show the pre-treatment radiographs and CBCT images of a 9.5-year-old Caucasian male who was referred by his GDP to an orthodontist regarding failure of eruption of his maxillary central incisors. Royal College DentalUpdate 735

GeneralDentistry/PaediatricDentistry/Orthodontics

a

a

surgeon in the patient’s care. Compliance with Ethical Standards

Conflict of Interest: The authors declare that they have no conflict of interest. Informed Consent: Informed consent was obtained from all individual participants included in the article.

b

b

References 1.

Figure 7. (a) Space creation and traction applied via ‘superthread’ to attachments bonded to maxillary central incisors. (b) Continuation of space creation and traction applied to attachments bonded to maxillary central incisors.

Figure 9. (a) ‘At deband’ (frontal view). (b) ‘At deband’ (occlusal view).

revealed the presence of a supernumerary tooth. Following discussion with the patient’s family, it was decided to bond attachments to the unerupted central incisors at the same time as removal of the supernumerary tooth. The patient underwent a course of sectional fixed appliance treatment to create sufficient space, facilitate guided traction and alignment of the incisors (Figures 7−9). Careful post-treatment monitoring will be required as patients with an anterior maxillary supernumerary tooth may be at increased risk of developing one or more late forming supernumerary teeth, especially in the lower premolar region.

a

b

Figure 8. (a) Aligning of maxillary right central incisor. (b) Continuation of aligning of maxillary right central incisor.

of Surgeons of England guidelines recommend that further investigation is warranted if: „ The maxillary central incisor does not erupt within 6 months of its contralateral incisor or within 12 months of eruption of the mandibular incisors; or „ The maxillary lateral incisor erupts before the central incisor.25 Radiographic investigation

736 DentalUpdate

Conclusions Supernumerary teeth are not uncommon and can be associated with a variety of effects on the dentition. The GDP should be aware of the characteristics that may indicate their presence, including delayed eruption of teeth and crowding, and should be able to carry out appropriate clinical and radiographic assessment. Once diagnosed, each patient should be managed appropriately to minimize (potential) deleterious effects to the dentition. This may require interdisciplinary involvement of an orthodontist and oral

Fleming P, Xavier G, DiBiase A, Cobourne M. Revisiting the supernumerary: the epidemiological and molecular basis of extra teeth. Br Dent J 2010; 208: 25−30. 2. Scheiner MA, Sampson WJ. Supernumerary teeth: a review of the literature and four case reports. Aust Dent J 1997; 42: 160−165. 3. Lubinsky M, Kantaputra PN. Syndromes with supernumerary teeth. Am J Med Genet A 2016; 170: 2611−2616. 4. Rajab L, Hamdan M. Supernumerary teeth: review of the literature and a survey of 152 cases. Int J Paediatr Dent 2002; 12: 244−254. 5. Brook A. A unifying aetiological explanation for anomalies of human tooth number and size. Arch Oral Biol 1984; 29: 373−378. 6. Tippett H, Cobourne MT. Supernumerary teeth. In: Orthodontic Management of the Developing Dentition. Cobourne M (ed). Springer, Cham, 2017. 7. Shah A, Gill DS, Tredwin C, Naini FB. Diagnosis and management of supernumerary teeth. Dent Update 2008; 35: 510−520. 8. Lu X, Yu F, Liu J, Cai W, Zhao Y, Zhao S et al. The epidemiology of supernumerary teeth and the associated molecular mechanism. Organogenesis 2017; 13: 71−82. 9. Garvey MT, Barry HJ, Blake M. Supernumerary teeth − an overview of classification, diagnosis and management. J Can Dent Assoc 1999; 65: 612−616. 10. Orhan AI, Özer L, Orhan K. Familial occurrence of nonsyndromal multiple supernumerary teeth: a rare condition. Angle Orthod 2006; 76: 891−897. 11. Subasioglu A, Savas S, Kucukyilmaz October 2020

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GeneralDentistry/PaediatricDentistry/Orthodontics

12.

13.

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18.

19.

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21.

E, Kesim S, Yagci A, Dundar M. Genetic background of supernumerary teeth. Eur J Dent 2015; 9: 153−158. Akcam MO, Evirgen S, Uslu O, Memikoğlu UT. Dental anomalies in individuals with cleft lip and/ or palate. Eur J Orthod 2010; 32: 207−213. Mundlos S. Cleidocranial dysplasia: clinical and molecular genetics. J Med Gen 1999; 36: 177−182. Chalakkal P, Krishnan R, De Souza N, Da Costa GC. A rare occurrence of supplementary maxillary lateral incisors and a detailed review on supernumerary teeth. J Oral Maxillofac Pathol 2018; 22: 149. Primosch RE. Anterior supernumerary teeth − assessment and surgical intervention in children. Pediatr Dent 1981; 3: 204−215. Kawashima A, Nomura Y, Aoyagi Y, Asada Y. Heredity may be one of the etiologies of supernumerary teeth. Pediatr Dent J 2006; 16: 115−117. Shilpa G, Gokhale N, Mallineni SK, Nuvvula S. Prevalence of dental anomalies in deciduous dentition and its association with succedaneous dentition: a crosssectional study of 4180 South Indian children. J Indian Soc Pedod Prev Dent 2017; 35: 56−62. Harris EF, Clark LL. An epidemiological study of hyperdontia in American blacks and whites. Angle Orthod 2008; 78: 460−465. Khalaf K, Robinson D, Elcock C, Smith R, Brook A. Tooth size in patients with supernumerary teeth and a control group measured by image analysis system. Arch Oral Biol 2005; 50: 243−248. Brook A, Griffin R, Smith R, Townsend G, Kaur G, Davis G et al. Tooth size patterns in patients with hypodontia and supernumerary teeth. Arch Oral Biol 2009; 54: S63− S70. Jimenez‐Rubio A, Segura J, Jimenez‐ Planas A, Llamas R. Multiple dens invaginatus affecting maxillary lateral incisors and a supernumerary tooth. Endod Dent Traumatol 1997; 13: 196−198.

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22. Cobourne MT, Sharpe PT. Making up the numbers: the molecular control of mammalian dental formula. Semin Cell Dev Biol 2010; 21: 314−324. 23. Yassin O, Hamori E. Characteristics, clinical features and treatment of supernumerary teeth. J Clin Pediatr Dent 2009; 33: 247−250. 24. Pippi R. Odontomas and supernumerary teeth: is there a common origin? Int J Med Sci 2014; 11: 1282−1297. 25. Seehra J, Yaqoob O, Patel S, O’Neill J, Bryant C, Noar J, Morris D, Cobourne M. National clinical guidelines for the management of unerupted maxillary incisors in children. Br Dent J 2018; 224: 779−785. 26. Mitchell L, Bennett T. Supernumerary teeth causing delayed eruption − a retrospective study. Br J Orthod 1992; 19: 41−46. 27. Ata-Ali F, Ata-Ali J, Peñarrocha-Oltra D, Peñarrocha-Diago M. Prevalence, etiology, diagnosis, treatment and complications of supernumerary teeth. J Clin Exp Dent 2014; 6: e414− e418. 28. Shah A, Hirani S. A late-forming mandibular supernumerary: a complication of space closure. J Orthod 2007; 34: 168−172. 29. Shetty R, Sandler PJ. Keeping your eye on the ball. Dent Update 2004; 31: 398−402. 30. Sian J. Root resorption of first permanent molar by a supernumerary premolar. Dent Update 1999; 26: 210−211. 31. Trejo-García W, Mendoza-Rodríguez M, Medina-Solís CE, VerasHernández MA, Lucas-Rincón SE, Casanova-Rosado JF. Supernumerary inversion in the palate of an infant: report of a clinical case. Pediatria (Asunción) 2018; 45: 237−241. 32. Chawla S, Singhal M, Yadav A. Ectopic supernumerary tooth in nasal cavity: a rare case report. Santosh Univ J Health Sci 2015; 1: 116−117. 33. Meade MJ, Weston A, Dreyer CW. Valid consent and orthodontic treatment. Aust Orthod J 2019; 35: 35−45. 34. Bharmal RV, Furness C, Slattery D,

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Campbell C. The multidisciplinary management of unerupted maxillary incisors. A report of three cases. Ortho Update 2016; 9: 122−128. Jacobs SG. Radiographic localization of unerupted maxillary anterior teeth using the vertical tube shift technique: the history and application of the method with some case reports. Am J Orthod Dentofacial Orthop 1999; 116: 415−423. Liu D-g, Zhang W-l, Zhang Z-Y, Wu Y-T, Ma X-C. Three-dimensional evaluations of supernumerary teeth using cone-beam computed tomography for 487 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 103: 403−411. SEDENTEXCT Guideline Development Panel. Radiation protection No 172. Cone beam CT for dental and maxillofacial radiology. Evidence-based guidelines. Luxembourg: European Commission Directorate-General for Energy, 2012. Horner K, O’Malley L, Taylor K, Glenny A-M. Guidelines for clinical use of CBCT: a review. Dentomaxillofac Radiol 2015; 44: 20140225. Mossaz J, Kloukos D, Pandis N, Suter VG, Katsaros C, Bornstein MM. Morphologic characteristics, location, and associated complications of maxillary and mandibular supernumerary teeth as evaluated using cone beam computed tomography. Eur J Orthod 2014; 36: 708−718. Kurol J. Impacted and ankylosed teeth: why, when, and how to intervene. Am J Orthod Dentofacial Orthop 2006; 129: S86−S90. Omer RS, Anthonappa RP, King NM. Determination of the optimum time for surgical removal of unerupted anterior supernumerary teeth. Pediatr Dent 2010; 32: 14−20. October 2020

OralSurgery

Enhanced CPD DO C

Claire Hopkins

Rhinosinusitis Update Abstract: Rhinosinusitis is a common condition, affecting more than one in ten adults. This article will review current management strategies. While multi-factorial in aetiology, odontogenic rhinosinusitis is an important subgroup that is often misdiagnosed and recalcitrant to management. Patients with rhinosinusitis often report facial pain, but when it is severe, and mismatched in severity to other sinonasal symptoms, facial migraine should be suspected. Finally, the risks of implantation in the setting of maxillary sinus mucosal thickening and the need for ENT referral in such cases will be discussed. CPD/Clinical Relevance: Sinus issues may present to a dentist as dental pain, and dental disease may itself cause sinusitis. With increasing use of cone beam imaging, sinus pathology will be detected frequently in dental practice and this review will help to advise practitioners on current best practice. Dent Update 2020; 47: 739–746

Introduction Rhinosinusitis is a condition of inflammation of the nose and paranasal sinuses. Rhinosinusitis is divided into acute and chronic forms. In Acute Rhinosinusitis (ARS) symptoms resolve within 12 weeks (although usually within 4 weeks) and often have an infective aetiology, while in Chronic Rhinosinusitis (CRS), symptoms last more than 12 weeks without complete resolution, with multiple potential aetiologies, which may include inflammation, infection and obstruction of sinus ventilation.1 CRS is subcategorized into Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) and without nasal polyps (CRSsNP), based on visualization of polyps on rhinoscopy or endoscopy. In a worldwide population study, 10.9% of UK adults reported CRS symptoms.2

Acute rhinosinusitis Acute rhinosinusitis is usually caused by a viral infection, and is usually self-limiting. NICE guidance3 advocates avoidance of

Claire Hopkins, BMBCH, MA(Oxon), FRCS(ORLHNS), DM, Professor of Rhinology, Guy’s Hospital, Great Maze Pond, London SE1 9RT, UK, (email: [email protected]). October 2020

antibiotic prescribing unless symptoms persist for more than 10 days, or if the patient has a high risk of complications, or is systemically very unwell. First choice antibiotics in such cases would be co-amoxiclav or doxycycline. A large number of high quality randomized trials support restricting usage of antibiotics.4 Although antibiotics can shorten resolution of the episode, only 1 in 20 benefits, while 1 in 8 will develop side-effects of antibiotic treatment. Despite this evidence, ARS accounts for over 20% of antibiotic prescriptions, with antibiotics being issued in over 90% of consultations for ARS.5

Chronic rhinosinusitis In contrast, most chronic rhinosinusitis (CRS) is associated with inflammation as the primary abnormality, with preservation of drainage pathways, although acute infective exacerbations may occur. It is thought that the persistent inflammation found in CRS is due to a dysfunctional host-environment, with abnormal responses of the mucosa to a wide variety of microbes and irritants. Targeting inflammation is therefore central to treatment options, rather than targeting the microbes or simple drainage procedures. This is reflected in the move away from antibiotic treatment in chronic disease. Chronic rhinosinusitis has been shown to have significant impact on quality

of life (QOL), with symptoms such as nasal obstruction, nasal discharge, facial pain, anosmia and sleep disturbance. Diagnosis of CRS is made by the presence of two or more persistent symptoms for at least 12 weeks without complete resolution, one of which should be nasal congestion/obstruction/nasal discharge and/or facial pain/pressure/ headache or loss/reduction in smell. Symptoms must be accompanied by endoscopic evidence of mucopurulent secretions, polyps or oedema or radiological evidence of disease, as a symptom-based diagnosis alone has high sensitivity but poor specificity − only 50% meeting the symptom-based definition have supporting objective signs of disease.6 First-line treatment in CRS usually includes a trial of intranasal corticosteroids (INCS) and saline irrigation. INCS have been shown to be effective in a large number of randomized trials, with a low incidence of adverse effects.7 This treatment is the same for both CRS with and without polyps, although steroid drops may be considered for patients with polyps to help achieve better nasal entry. Patients should be advised that steroid sprays work best when used regularly and do not perform well as a rescue medication. It is important that compliance is encouraged. Daily large volume saline irrigation should be recommended,8 and a number DentalUpdate 739

OralSurgery

a

b

Figure 2. Odontogenic sinusitis, periapical lucency and extensive opacification of the ipsilateral sinuses. The patient developed orbital cellulitis and an extradural collection secondary to the odontogenic infection.

Figure 1. Pre-operative CT and endoscopy images. (a) The cleft between the free posterior margin of the uncinate process, marked in blue on the CT and outlined in blue on the endoscopy image below: the ethmoid bulla is known as the hiatus semilunaris, and is key to the drainage of the anterior ethmoid, maxillary and frontal sinuses. This common drainage pathway is called the ostiomeatal complex. During functional endoscopic sinus surgery, the uncinate is removed along its anterior margin (marked in yellow) to expose the maxillary sinus ostium and the ethmoidal bulla and partitions are removed to remove any obstruction to sinus drainage and allow topical access to the sinuses. (b) The post-operative CT shows the widely opened sinus cavities; on the endoscopic image the frontal recess (F) skull base and maxillary sinuses are exposed.

of positive pressure squeeze bottles or irrigation jugs are available commercially. Antibiotics are not recommended for routine management of CRS, except in the setting of an acute exacerbation. Patients with CRS often receive multiple courses of oral antibiotics that may increase risk of antibiotic resistance. There is little evidence for any benefit of short-term oral antibiotics in CRS. There is weak evidence for the use of a 12-week course of a low dose macrolide,9 in highly selected patients with CRSsNP, although there is a small risk of cardiac toxicity.10

740 DentalUpdate

Patients who fail to achieve sufficient symptomatic control with medical treatment may be considered for surgery. Surgical intervention typically involves endoscopic sinus surgery to open and ventilate sinuses, restore normal mucociliary functioning and improve access to topical steroids (Figure 1). ‘Functional’ endoscopic surgery focuses on opening the ostiomeatal complex, and the key drainage pathway of the maxillary, anterior ethmoid and frontal sinuses in the middle meatus. Inferior meatal antrostomies and sinus wash-outs are no longer performed as they do not improve mucociliary drainage.

In more extensive sinus disease, or in the presence of tumours, extended procedures may be undertaken, including complete ethmoidectomy, sphenoidotomy, medial maxillectomy and median drainage of the frontal sinuses. Use of navigation systems may facilitate surgical dissection in the setting of complex anatomical variations or revision cases. Nasal polyp removal, surgery to manage underlying nasal abnormalities such as septal deviation, or turbinate hypertrophy may also be performed. Studies have shown greater benefits in surgery performed at an early stage in the disease process.11 Currently, commissioning restrictions and delays in primary care result in 50% of patients who currently undergo endoscopic sinus surgery waiting for more than 5 years from the onset of symptoms of CRS, potentially missing the window of greatest benefit. Although up to 15% of patients with CRSwNP require revision surgery over a 5-year period, surgery improves the effectiveness of ongoing topical therapy and achieves significant improvements in disease-related quality of life that is maintained long term.12

Facial pain and rhinosinusitis Facial pain is reported by 50% of patients with CRS, but is infrequently severe and usually mirrors the severity of other nasal October 2020

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OralSurgery

Figure 3. Right-sided maxillary mucous retention cyst.

symptoms. When pain is severe, and is the main presenting symptom, then a careful history for migraines should be taken, and key features of the pain should be elicited. Indeed, facial pain, particularly if reported as ‘throbbing‘ or associated with light sensitivity, has a significant negative predictive value in diagnosing CRS; its presence makes CRS LESS likely.13 This is also found when there is a mismatch in the severity of facial pain and aural fullness compared with the overall severity of nasal symptoms,14 or a mismatch in the severity of symptoms and endoscopy and radiological scores.15 Facial migraine is commonly misdiagnosed by both patients and physicians as chronic or recurrent acute rhinosinusitis; it typically presents with severe pain over the paranasal sinuses and is often associated with tenderness over the glabellar area, and may be accompanied by congestion and clear rhinorrhoea. Pain is usually intermittent, but episodes can be frequent and are often exacerbated by overuse of codeine analgesia. Often patients are given repeated courses of antibiotics, but with limited effectiveness. Of patients who met IHS criteria for migraines, 84% of patients reported sinus pressure, 82% reported pain in the sinus areas, 63% reported nasal congestion, and 40% reported rhinorrhea at the time of their initial consultation16 − it is therefore easy to understand why the symptoms are thought to arise in the sinuses. Vasodilation, occurring as a downstream effect of October 2020

Figure 4. Management algorithm for mucosal thickening discovered during pre-implantation planning.

migraines, may cause sinonasal symptoms, and may be relieved by the use of decongestants, thereby falsely re-affirming the diagnosis of sinogenic headache.17 In a large series of nearly 3000 patients with self diagnosed sinus headache, 88% were found to have migraine and 8% tension headaches.18 Recurrent acute rhinosinusitis is actually very rare, and facial migraine should certainly be considered in the setting of frequent intermittent episodes of facial pain in the absence of mucopurulent discharge. Often, endoscopy or a CT scan performed during an acute episode is required to differentiate between the two, as imaging performed in between episodes. In one study of patients referred to tertiary care thought to be having recurrent episodes of ARS, CT performed at baseline was normal at baseline and remained so when repeated at the time of an acute episode, excluding recurrent ARS in 96% of cases:19 47% were ultimately diagnosed with rhinitis, 37% with migraine, and 12.5% with otherwise unspecified facial pain. Correct and early diagnosis of migrainous headache is important, both to achieve adequate symptom control and to avoid unnecessary and often repeated courses of medical, and sometimes surgical, treatment. One patient,

referred to my practice with ‘recalcitrant recurrent acute sinusitis’, had undergone seven sinus procedures despite no evidence of mucosal thickening or other radiological signs of CRS, but made an excellent response to treatment for facial migraine. Within specialist clinics, ‘upfront’ CT should be considered in patients with negative endoscopy before prescribing ‘maximal medical therapy’ and reinforcing a diagnosis of sinus disease.20 Primary care and dental practitioners should similarly avoid reinforcing patient perceptions of a sinogenic headache, unless there is clear supporting evidence on examination or radiology.

Odontogenic sinusitis Odontogenic sinusitis, where a dental origin is identified clinically, radiologically, or suggested by anaerobic predominance on culture, may present as an acute or chronic picture. It is estimated that 10% of all sinusitis cases, and up to 40% of recalcitrant maxillary sinusitis cases,21,22 have an odontogenic cause. The incidence of odontogenic sinusitis appears to be increasing,23 possibly related to the rising rates of dental implantation.24 Only 50% of patients have a history of previous dental DentalUpdate 743

OralSurgery

surgery or known periapical disease25 and, as dental pain is often absent, odontogenic disease may present directly to ENT, where the diagnosis can be easily missed.26 Foul-smelling unilateral mucopurulent nasal discharge should raise suspicion of an odontogenic sinusitis. Facial pain and pressure, nasal obstruction and post-nasal drip may also be reported. Anterior rhinoscopy and endoscopy, which may reveal mucopurulence and oedema in the middle meatus, and dental examination, are helpful in making the diagnosis but radiological imaging is essential. CT is considered the gold standard (Figure 2), as high rates of false negatives are reported with periapical radiography.27 Ideally, if CBCT is used, the field of view should include the ostiomeatal complex, the drainage pathway of the maxillary sinus found in the superomedial aspect of the sinus. Anaerobic streptococci, gramnegative bacilli and enterobacteriae are the most commonly isolated microbes,28 although infections are usually polymicrobial. Initial medical management should include nasal decongestants and appropriate broad-spectrum antibiotics, such as co-amoxiclav or clindamycin. The dental origin should be addressed. While many patients will settle with conservative management, sinus surgery will likely be required in up to 50% of cases;29 this is more likely if there is a history of preceding dental procedure (particularly implantation) or if there is obstruction to the drainage of the maxillary sinus.

Management of the sinuses prior to dental implantation No doubt driven by a wish to avoid iatrogenic odontogenic sinusitis, an increasing number of patients appear to be being referred to the NHS to investigate incidental findings in the maxillary sinus found on CBCT prior to implantation. There are currently few published studies upon which to guide management in such cases, although the British Rhinological Society are in

744 DentalUpdate

the process of developing a consensus document. One of the most common incidental findings is a mucosal retention cyst (Figure 3); these are found in a third of CT scans performed for non-rhinological conditions and are not a manifestation of rhinosinusitis.30 They are rarely symptomatic and have a high recurrence rate after marsupialisation, and therefore treatment is not required. Mucosal thickening is also common in the absence of sinus disease. A study of patients undergoing sinus imaging for non-sinusitis causes found that only 25% had no mucosal thickening, with a mean Lund-Mackay score (a staging system that quantifies the amount of mucosal thickening on a scale of 0−24) of 4.26.31 Dental literature defines rhinosinusitis based on radiological thickening of the mucosa of >2 mm,32 but this definition has poor specificity and will include many healthy asymptomatic patients. The presence of mucosal thickening on CT has been shown not to affect the success of dental implants. In one study, with strict inclusion criteria, 29 CBCT scans were being evaluated prior to dental implantation. Of these, 6.9% had minimal thickening (1−2 mm), 20.7% of cases had moderate thickening (2−5 mm), and 65.5% had severe thickening (>5 mm). There was a 100% success rate of the implants with no loss of implantation or infection.33 This is also supported by a study by Jungner et al, in 2014, whereby radiographic signs of sinus pathology, opacification, polyp-like structures, and thickening of the sinus membrane, were not correlated to implant survival.34 A key feature is whether the drainage pathway of the maxillary sinus, the ostiomeatal complex, is patent; this should be included in the field of view on cone beam imaging if rhinosinusitis is suspected. If the drainage pathway is unobstructed, there is only mild mucosal thickening and, if the patient is asymptomatic, there is no need for ENT assessment. In all other cases, onward ENT referral should be made, with transfer of the appropriate imaging. As NHS systems are often unable to open CDs or import images, it can be helpful to ask the patient to take pictures of relevant images on their smartphone. A treatment

algorithm is proposed in Figure 4.

Conclusions Rhinosinusitis is a common chronic condition requiring early, correct diagnosis, medical management and, at times, surgical intervention. Radiological imaging may be required to distinguish between facial migraine in the setting of normal endoscopy. Odontogenic sinusitis should be considered with unilateral rhinosinusitis, and expedient management of the dental cause will result in resolution in over 50% of cases. Mild mucosal thickening and mucous retention cysts in the maxillary sinus are not contra-indications to dental implantation, but ENT assessment is advised if the sinus drainage is obstructed. Compliance with Ethical Standards

Conflict of Interest: The author declares that that there is no conflict of interest. Informed Consent: Informed consent was obtained from all individual participants included in the article.

References 1.

2.

3.

4.

5.

6.

Fokkens WJ, Lund VJ, Mullol J et al. European Position Paper on Rhinosinusitis and Nasal Polyps 2012. Rhinol Suppl 2012; 23: 1−298. Hastan D, Fokkens WJ, Bachert C et al. Chronic rhinosinusitis in Europe − an underestimated disease. A GA(2)LEN study. Allergy 2011; 66: 1216−1223. NICE. Sinusitis (acute): antimicrobial prescribing. NICE guideline (NG79) 27 October 2017. Lemiengre MB, van Driel ML, Merenstein D, Liira H, Makela M, De Sutter AI. Antibiotics for acute rhinosinusitis in adults. Cochrane Database Syst Rev. 2018; 9: CD006089. Ashworth M, Charlton J, Ballard K, Latinovic R, Gulliford M. Variations in antibiotic prescribing and consultation rates for acute respiratory infection in UK general practices 1995−2000. Br J Gen Pract 2005; 55: 603−608. Bhattacharyya N, Lee LN. Evaluating the diagnosis of chronic rhinosinusitis based on clinical guidelines and endoscopy. Otolaryngol Head Neck Surg October 2020

LTD

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OralSurgery

7.

8.

9.

10.

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12.

13.

14.

15.

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2010; 143: 147−151. Chong LY, Head K, Hopkins C, Philpott C, Schilder AG, Burton MJ. Intranasal steroids versus placebo or no intervention for chronic rhinosinusitis. Cochrane Database Syst Rev 2016; 4: CD011996. Chong LY, Head K, Hopkins C et al. Saline irrigation for chronic rhinosinusitis. Cochrane Database Syst Rev 2016; 4: CD011995. Wallwork B, Coman W, Mackay-Sim A, Greiff L, Cervin A. A double-blind, randomized, placebo-controlled trial of macrolide in the treatment of chronic rhinosinusitis. Laryngoscope 2006; 116: 189−193. Schembri S, Williamson PA, Short PM et al. Cardiovascular events after clarithromycin use in lower respiratory tract infections: analysis of two prospective cohort studies. Br Med J 2013; 346: f1235. Hopkins C, Rimmer J, Lund VJ. Does time to endoscopic sinus surgery impact outcomes in Chronic Rhinosinusitis? Prospective findings from the National Comparative Audit of Surgery for Nasal Polyposis and Chronic Rhinosinusitis. Rhinology 2015; 53: 10−17. Hopkins C, Slack R, Lund V, Brown P, Copley L, Browne J. Long-term outcomes from the English national comparative audit of surgery for nasal polyposis and chronic rhinosinusitis. Laryngoscope 2009; 119: 2459−2465. Hsueh WD, Conley DB, Kim H et al. Identifying clinical symptoms for improving the symptomatic diagnosis of chronic rhinosinusitis. Int Forum Allergy Rhinol 2013; 3: 307−314. Wu D, Gray ST, Holbrook EH, BuSaba NY, Bleier BS. SNOT-22 score patterns strongly negatively predict chronic rhinosinusitis in patients with headache. Int Forum Allergy Rhinol 2019; 9: 9−15. Lal D, Rounds AB, Rank MA, Divekar R. Clinical and 22-item Sino-Nasal Outcome Test symptom patterns in primary headache disorder patients presenting to otolaryngologists with “sinus” headaches, pain or pressure. Int Forum Allergy Rhinol 2015; 5: 408−416. Schreiber CP, Hutchinson S, Webster CJ, Ames M, Richardson MS, Powers C.

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17.

18.

19.

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21.

22.

23.

24.

25.

26.

27.

Prevalence of migraine in patients with a history of self-reported or physiciandiagnosed “sinus” headache. Arch Intern Med 2004; 164: 1769−1772. Bellamy JL, Cady RK, Durham PL. Salivary levels of CGRP and VIP in rhinosinusitis and migraine patients. Headache 2006; 46: 24−33. Eross E, Dodick D, Eross M. The Sinus, Allergy and Migraine Study (SAMS). Headache 2007; 47: 213−224. Barham HP, Zhang AS, Christensen JM, Sacks R, Harvey RJ. Acute radiology rarely confirms sinus disease in suspected recurrent acute rhinosinusitis. Int Forum Allergy Rhinol 2017; 7: 726−733. Leung RM, Chandra RK, Kern RC, Conley DB, Tan BK. Primary care and upfront computed tomography scanning in the diagnosis of chronic rhinosinusitis: a cost-based decision analysis. Laryngoscope 2014; 124: 12−18. Troeltzsch M, Pache C, Troeltzsch M et al. Etiology and clinical characteristics of symptomatic unilateral maxillary sinusitis: a review of 174 cases. J Craniomaxillofac Surg 2015; 43: 1522−1529. Melen I, Lindahl L, Andreasson L, Rundcrantz H. Chronic maxillary sinusitis. Definition, diagnosis and relation to dental infections and nasal polyposis. Acta Otolaryngol 1986; 101: 320−327. Hoskison E, Daniel M, Rowson JE, Jones NS. Evidence of an increase in the incidence of odontogenic sinusitis over the last decade in the UK. J Laryngol Otol 2012; 126: 43−46. Lopes LJ, Gamba TO, Bertinato JV, Freitas DQ. Comparison of panoramic radiography and CBCT to identify maxillary posterior roots invading the maxillary sinus. Dentomaxillofac Radiol 2016; 45: 20160043. Maillet M, Bowles WR, McClanahan SL, John MT, Ahmad M. Cone-beam computed tomography evaluation of maxillary sinusitis. J Endod 2011; 37: 753−757. Cartwright S, Hopkins C. Odontogenic Sinusitis an underappreciated diagnosis: our experience. Clin Otolaryngol 2016; 41: 284−285. Shahbazian M, Jacobs R. Diagnostic

28.

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34.

value of 2D and 3D imaging in odontogenic maxillary sinusitis: a review of literature. J Oral Rehabil 2012; 39: 294−300. Brook I. Sinusitis of odontogenic origin. Otolaryngol Head Neck Surg 2006; 135: 349−355. Mattos JL, Ferguson BJ, Lee S. Predictive factors in patients undergoing endoscopic sinus surgery for odontogenic sinusitis. Int Forum Allergy Rhinol 2016; 6: 697−700. Kanagalingam J, Bhatia K, Georgalas C, Fokkens W, Miszkiel K, Lund VJ. Maxillary mucosal cyst is not a manifestation of rhinosinusitis: results of a prospective three-dimensional CT study of ophthalmic patients. Laryngoscope 2009; 119: 8−12. Ashraf N, Bhattacharyya N. Determination of the “incidental” Lund score for the staging of chronic rhinosinusitis. Otolaryngol Head Neck Surg 2001; 125: 483−486. Cagici CA, Yilmazer C, Hurcan C, Ozer C, Ozer F. Appropriate interslice gap for screening coronal paranasal sinus tomography for mucosal thickening. Eur Arch Otorhinolaryngol 2009; 266: 519−525. Maska B, Lin GH, Othman A et al. Dental implants and grafting success remain high despite large variations in maxillary sinus mucosal thickening. Int J Implant Dent 2017; 3: 1. Jungner M, Legrell PE, Lundgren S. Follow-up study of implants with turned or oxidized surfaces placed after sinus augmentation. Int J Oral Maxillofac Implants 2014; 29: 1380−1387.

CPD ANSWERS July/August 2020 1. C

6. B

2. C

7. B

3. C

8. B

4. A

9. B

5. B

10. B October 2020

Endodontics

Enhanced CPD DO C

Manahil Maqbool Tahir Yusuf Noorani Jawaad Ahmed Asif, Saleem D Makandar and Nafij Bin Jamayet

Controversies in Endodontic Access Cavity Design: a Literature Review Abstract: The purpose of this article is to compare and contrast the different types of endodontic access cavity designs based on the current available evidence. Four types of access cavity designs, namely, traditional endodontic access cavity design (TEC), contracted/ conservative endodontic access cavity design (CEC), ultra-conservative or ninja endodontic access cavity design (NEC) and truss endodontic access cavity design (TREC) have been suggested, and the latter three are currently in the limelight. Studies in vitro have been performed comparing the TECs, CECs, TRECs and NECs; except for the TECs, the other three types have not undergone clinical trials on patients. The choice of endodontic access cavity design affects fracture strength of the tooth, but remnants of pulpal tissue, due to ineffective instrumentation, can cause root canal treatment failure. CPD/Clinical Relevance: Root canal treatment with new access cavity designs has been proposed. However, there is lack of evidence to support such practices. It is important to consider the potential deleterious effects of such access cavity designs rather than emphasizing the preservation of tooth structure alone. Dent Update 2020; 47: 747–754

Although the role of caries removal and root canal disinfection cannot be overemphasized, there is considerable

Manahil Maqbool, BDS, MSc, Postgraduate Student, Paediatric Dentistry Unit, Tahir Yusuf Noorani, DDS, MResDent, FRACDS, Senior Lecturer, Conservative Dentistry Unit (email: [email protected]), Jawaad Ahmed Asif, BDS, MOMS, FRACDS, Senior Lecturer, Oral and Maxillofacial Surgery Unit, Saleem D Makandar, BDS, MDS, Senior Lecturer, Conservative Dentistry Unit and Nafij Bin Jamayet, BDS, Grad DipClinSc, MScDent, Senior Lecturer, Prosthodontics Unit, School of Dental Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kota Bharu, Kelantan, Malaysia. October 2020

controversy regarding the size of the preparation of the access cavity and the parameters of the preparation of the root canal. The need for dentine conservation cannot, however, be understated.1 Direct access to the root canal system is one of the purposes of an endodontic access cavity. The traditional endodontic access cavity (TEC) design focuses on the inclusion of all pulp horns and the removal of the roof of the pulp chamber so that the coronal portion of the root canal system is sufficiently debrided (Figure 1 a, b).2 This approach has been contested by the radical design of the access cavity that has been proposed in recent years. It stressed the preservation of pericervical dentine (PCD) and suggested that it was not necessary to unroof the pulp chamber completely.1 The interest in minimally invasive endodontics is enabled by new technologies and

techniques that maximize residual dentine.3 The designs of the endodontic access cavity and cumulative loss of tooth structure appear to influence the fracture strength of endodontically treated teeth greatly.4 The amount of the residual dental substance could be affected by the preparation of the endodontic access cavity. Therefore, inspired by the minimally invasive concept of restorative dentistry, a conservative endodontic access cavity (CEC) (Figure 1 c, d) preparation was proposed to preserve as much tooth structure as possible.1 Some endodontists underlined this principle by creating ultra conservative endodontic access cavities ‘ninja’ and ‘truss’ (NEC and TREC, respectively).5,6 An NEC is a small cavity on the occlusal surface that should enable the clinician to find and access all the orifices of the canal system (Figure 1 e, f ).2 The other approach is orifice-directed DentalUpdate 747

Endodontics

of this article is to describe the various newly proposed endodontic access cavity designs, review the literature, and suggest best clinical practice based on the current available evidence.

Access cavity preparation

Figure 1. An artist’s impression showing the different access cavity designs and the possible amount of tooth structure removal in a mandibular molar (a−b) TEC, (c−d) CEC, (e−f) NEC, (g−h) TREC.

Figure 2. A radiograph showing the pericervical dentine (PCD), which is the most common area of catastrophic restorative/root fracture and should be preserved. Additionally, overhanging pulp chamber roof that should be preserved is also shown.

design (also called the ‘truss’ access cavity) in which separate cavities are prepared to approach the mesial and distal canal systems in a mandibular molar (Figure

748 DentalUpdate

1 g, h), whereas for maxillary molars the mesiobuccal and distobuccal canals are accessed through one cavity and the palatal canal through another.7 The purpose

The access cavity preparation generally refers to the part of the cavity from the occlusal table to the canal orifices. Black’s principles of cavity preparation, including outline, convenience, retention, and resistance forms, speculate the basis of TEC. The outline form of the endodontic cavity must be correctly shaped and positioned to establish complete access for instrumentation, from cavosurface margin to apical foramen. Convenience form, as conceived by Black, is a modification of the cavity outline form to establish greater convenience in the placement of intracoronal restorations. Later, removal of the remaining carious dentine and defective restorations in an endodontic cavity preparation is necessary. It must be removed for three reasons: 1. To eliminate as many bacteria as possible from the interior of the tooth mechanically; 2. To eliminate the discoloured tooth structure that may ultimately lead to staining of the crown; 3. To reduce the risk of bacterial contamination of the prepared cavity.8 Another important reason to eliminate undermined and unsupported tooth structure is to evaluate whether the tooth is restorable or not, and also to minimize the possibility of tooth fracture in future. It is imprudent and unlikely that a clinician would leave the structure of the diseased tooth intact to create a textbook access cavity.9 In 2010, Clark and Khademi introduced the concept of contracted endodontic access cavity design, in a series of case reports.10 The basis of a CEC was kept in terms of saving the pericervical dentine (PCD) and leaving small overhangs of the pulp chamber roof behind. The most important tooth structure responsible for long-term survival is considered to be the PCD, the dentine structure located 4 mm below and 4 mm above the alveolar crest1 (Figure 2), which serves as the neck of the tooth and is responsible for distribution of functional and mechanical stresses inside the tooth.11,12 More of the occlusal October 2020

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Endodontics

tooth structure can be sacrificed than the cervical tooth structure, as the key pericervical tooth structure should remain as unaltered as possible.1 A new contracted access cavity, using a different set of burs than those used for TEC, was suggested. In a CEC, measurement reference points may change; for example, in the past, the reference for the mesial canals of mandibular molars was often the corresponding MB cusp. Now it may be found as a reference more to the distal, as it would preserve PCD and overhanging dentine. The simultaneous placement of 4 or 5 gutta-percha points for a cone fit radiograph in the more constricted access may be difficult without trimming to eliminate binding. Clark and Khademi recommended not removing the pulp tissue under the overhang until the obturation was finished; that way the operator only has to clean it once.10 Another approach to the conservation of tooth structure is the orifice-directed design (TREC) (also known as the ‘truss’ access cavity) in which separate cavities are prepared. The main objective of these access cavity designs is to preserve strategic dentine (ie to leave a dentine bridge between the two cavities thus prepared).2 In TREC, the cavities are prepared over the mesial and distal canals of the mandibular tooth, respectively, guided by computed tomographic images. The pulp chamber roof is maintained beneath the ‘truss’ of the tooth structure, between the mesial and distal cavities.2 However, TREC significantly impaired the debridement of the pulp chamber.5 Only one case report has been published so far regarding a ‘truss’ type cavity design, however, no follow-up of this case was presented.13 Hence, the long-term outcome of this type of treatment is unknown. Another ultra-conservative technique has recently been introduced, which is also known as the ‘ninja’ access cavity design.6 An NEC is actually an even smaller access cavity than the one made for a CEC on the occlusal surface, that should enable the clinician to find and access all the orifices of the canals, but there is not sufficient data or literature discussing this type. However, the NEC could jeopardize the complete removal of infected pulp tissue October 2020

Figure 3. Diagrammatic view of the three access cavities in maxillary anterior teeth: (a) lingual cingulum access cavity; (b) lingual conventional access cavity; (c) incisal straight-line access cavity. Adapted from Mannan et al. 14

from the pulp chamber and make canal instrumentation more difficult and less safe.

Histological evaluation In a study conducted on mandibular molars, one type of CEC design (Truss access) was tested, to acertain whether it was able to debride the pulp chamber completely or not, and to evaluate the remaining pulp tissue (RPT) in both experimental group the (TREC) and control group (TEC). Although both groups showed the presence of RPT in the pulp chamber, the amount in the TEC group was significantly lower than that of the TREC group. There was no substantial difference in RPT present in the isthmus (within the canals) between the TEC and TREC groups at any level.2 Only the area of the pulp chamber under the truss was assessed, which could serve as a nutritional source for the remaining bacterial biomass, leading to persistent infection. The results of this study showed two important findings: the pulp chamber showed a significantly reduced amount of remaining pulp tissue in TEC compared to TREC access, and there was no difference in the amount of remaining tissue in the root canals, close to and at the isthmus area of the root thirds between the two access cavity designs. In another study, the effect of different access cavity designs (lingual cingulum, lingual conventional and incisal straight-line) (Figure 3) on the ability of endodontics files to plane the root canal walls in maxillary anterior teeth was tested.14 It was found that instrumentation did not allow the entire root canal wall to be instrumented during the preparation

of canals, irrespective of the access cavity design. However, the incisal straight-line access cavity allowed a larger proportion of the root canal walls to be instrumented as compared to the conventional lingual access cavity and the cingulum access cavity.14 Nevertheless, it is still uncertain what happens to the incisal part of the pulp chamber in incisal straight-line and lingual cingulum access, as no histological evaluation was performed to identify any remaining pulp tissue under the pulp horns. Whether the pulp remnants and possible remaining bacterial biomass would later be troublesome for the patient or not, is still unknown. Further investigations are required to establish the prognosis of root canal treatment in both anterior and posterior teeth with these new designs. Furthermore, no study has been done so far to identify possible remaining pulp tissue in the pulp chamber in other CEC and NEC designs. This holds relevance as the pulp chamber is not completely unroofed and remaining infected pulp tissue under the pulp horns may lead to contamination of the rest of the root canal system and subsequent failure.

Fracture testing Fracture tests are used primarily to compare the fracture strength or fracture resistance of teeth. Various studies that compared the fracture resistance of endodontically treated teeth with different access cavity designs are listed in Table 1. It has been shown that conservative endodontic access cavity designs, specifically the ‘ninja’ and ‘truss’ DentalUpdate 751

Endodontics

Author Krishan et al

15

Purpose of Study

Methodology

Outcomes

Assess impacts of conservative endodontic cavity on root canal. Instrumentation and resistance to fracture.

Intact extracted human teeth assigned to CEC & TEC groups. Pre- and post-canal treatment micro CT was done. UCL and DVL for each tooth type was analysed. Fracture loading using Instron Universal Testing Machine done.

CEC compromised canal instrumentation only in the distal canals of lower molars, but it conserved coronal dentine, which increased fracture resistance. No difference in fracture resistance in anterior teeth with different access cavity designs.

Moore et al21

Assess impacts of contracted endodontic cavities (TEC vs CEC) on instrumentation and biomechanical responses.

Intact extracted human molars assigned to CEC & TEC groups. Pre- and post-canal treatment micro CT was done. Linear strain gauge was attached to teeth and were subjected to load cycles (50−150 N) in the Instron Universal Testing machine, and the axial micro strain was recorded.

CECs did not impact instrumentation efficacy and biomechanical responses compared with TECs. No difference between groups in terms of fracture resistance.

Chlup et al18

Assess fracture behaviour of teeth with conventional and mini-invasive access cavity designs (TEC vs CEC).

Intact extracted human teeth were assigned to CEC & TEC groups. All specimen teeth embedded in the resin and loaded until fracture using Instron Universal Testing Machine.

No significant difference between CEC and TEC in terms of fracture resistance but higher fracture load was required for CEC.

Plotino et al16

Assess fracture strength of endodontically treated teeth with different access cavity designs (TEC, CEC, NEC).

Extracted human teeth were assigned to control (intact teeth), TEC, CEC, or NEC groups. Teeth were endodontically treated and restored. Specimens then loaded to fracture in a mechanical material testing machine. The maximum load at fracture and fracture pattern (restorable or unrestorable) were recorded.

NEC did not increase fracture strength compared with CEC. Teeth with TEC access showed lower fracture strength than the ones prepared with CEC or NEC.

Rover et al22

Assess influence of access cavity design (TEC, CEC) on root canal detection, instrumentation efficacy, and fracture resistance.

Extracted intact molars were scanned with micro–computed tomographic imaging and assigned to CEC or TEC group. After root canal preparation non-instrumented canal area, hard tissue debris accumulation, canal transportation, and centring ratio analysed. After cavity restoration fracture resistance test done.

No associated benefits with CECs could be proved as compared to TEC. Lower ability of root canal detection and higher incidence of canal transportation was noted with CEC.

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October 2020

Endodontics

Author

Methodology

Outcomes

Assess impact of access cavity design (CEC & NEC) and root canal taper on fracture resistance.

For tapering assessment, 30 sound distobuccal roots of maxillary molars were randomly assigned to 1 of 3 groups, 0.04 taper, 0.06 taper, or 0.08 taper. After canal preparation fracture resistance was tested using a universal testing machine.

Increasing root canal taper can reduce fracture resistance. NEC in comparison with CEC had no significant impact on fracture resistance.

Corsentino et al5

Assess influence of access cavity design (TEC, CEC, TREC) and remaining tooth substance on fracture strength.

Sound molar teeth were selected. After access cavity preparation, all test teeth were endodontically treated and restored. The specimens were then loaded to fracture in a universal loading machine.

TREC & CEC do not increase the fracture strength of endo treated teeth, rather the loss of mesial and distal ridges reduced fracture strength of teeth significantly.

Özyürek et al24

Assess the effects of endodontic access cavity preparation design (TEC, TREC) and different restorative base material on the fracture strength.

Intact molar teeth were randomly assigned to TEC or TREC group (with one marginal wall missing), restored with either SDR or EverX posterior as base material. Sample loaded after restoration until fracture.

TREC did not increase the fracture strength of teeth. No difference in the fracture strength between teeth with TEC or TREC when the same base material was used

Sabeti et al

23

Purpose of Study

Abbreviations: UCL − Untouched Canal Wall; DVL − Dentine Volume Removed; CEC − Conservative Endodontic Access Cavity; TREC − Truss Endodontic Access Cavity; TEC − Traditional Endodontic Access Cavity; NEC − Ninja Endodontic Access Cavity. Table 1. List of studies that compared the effects of different access cavity designs on the fracture strength and instrumentation efficacy. Studies published until 31 December 2018 were included.

types, are successful in maintaining the pericervical dentine, and hence increasing the fracture resistance of the tooth. However, a group of researchers concluded that it was the loss of the mesial or distal marginal ridge that affected the fracture resistance of endodontically treated teeth rather than the access cavity design itself.5 Furthermore, Krishan et al15 found no advantage of conservative access cavity design over traditional design in terms of fracture resistance in anterior teeth. Another study compared teeth with different access cavity designs and sound teeth. It was found that unrestorable type fractures after fracture testing were noted considerably more often than the restorable type in access teeth, irrespective of the access cavity design.16 Besides, a huge limitation to the findings of the previous studies is that all of them were performed in vitro on almost non-carious October 2020

teeth, and the age of the patients, from whom the teeth were extracted, was not recorded. As with the increasing age of the patient, the brittleness and hence the fracture ability of a tooth increases,17 it is necessary that the age be considered and mentioned. Furthermore, all these studies used static loading to determine the fracture strength. Ideally, cyclic loading, as compared to static loading, would correspond better to the natural loading during chewing. Additionally, there was no simulation of periodontal ligament in most of these studies. Although this simulation is necessary, a standardized periodontal ligament simulation model has not yet been introduced.18

The challenges and changes Bio-minimalism recognizes that the pericervical dentinal (PCD) zone is essential to support the residual coronal tooth

structure during functional loading stress, and acts ostensibly to minimize cuspal flexion during mastication.9 However, the fracture strength of endodontically treated teeth could also be affected by insufficient dental residue, due to the caries causing the loss of one or more dentinal walls.19 Fortunately, technological advances in armamentarium has brought the objectives of minimally invasive endodontics closer. Cone beam computed tomography aids the clinician in avoiding the removal of excessive hard tissue by allowing assessment of the angulation and orientation of the root canals.9 Despite the limited clinical evidence for the use of contracted access cavity designs, the growing interest and technological advances in image-guided endodontics can prove to be a paradigm shift in root canal treatment.2 Besides, we now have DentalUpdate 753

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files and finishers that adjust to the original canal shape, scrape biofilm in a way similar to periodontal scalers and make it easier for irrigants to act on exposed microbes.9 Furthermore, with the advent and use of the dental operating microscope, root canals can be detected and cleaned optimally, even through minimally invasive endodontic access cavities. However, currently there is little evidence (mainly from in vitro studies) available to prove that conservative and ultra-conservative access cavity designs are advantageous over their traditional counterpart, especially when the need to clean the root canal adequately remains an overarching objective of non-surgical endodontic treatment.2 Besides, no clinical trials have been reported so far on patients with these newly introduced contracted cavity designs. Additionally, owing to the fact that pulpal remnants were seen in the pulp chamber while examining the histological sections of the ‘truss’ type CEC,2 the longterm success rate is unknown. Perhaps case selection (based on multifactorial evaluation, including the condition of the pulp, vital or necrotic), level of difficulty (presence of calcifications, curvatures, etc) and accessibility, in addition to the equipment and facilities available, would serve as a reason in which conservative access cavities could be prepared for certain cases without compromising the ability to locate all canals and the efficiency of subsequent root canal treatment procedures.20

Conclusion Currently, there is no conclusive evidence to suggest that conservative or ultraconservative access cavity design can help retain endodontically treated teeth longer by increasing their fracture resistance. Furthermore, there is no conclusive evidence that the biological principles (complete disinfection) of endodontic treatment can be adequately achieved with these conservative access cavity designs. Hence, conservative or ultra-conservative access cavity designs should be used with extreme caution. Perhaps the objective of conservative cavity preparation should be avoided from ‘removing the smallest possible tooth structure’ to ‘removing as little as necessary’. Besides, to validate these newly introduced access cavity designs, more research needs to be conducted, as the studies remain few and

754 DentalUpdate

stress distribution in human dental supporting

fragmentary.

structures. Arch Oral Biol 2000; 45: 543−550.

Acknowledgement

The authors acknowledge the financial support in preparation of this article from Universiti Sains Malaysia (shortterm research grant scheme no. 304/ PPSG/6315195).

12.

alveolar system using digital photoelasticity. Proc Instn Mech Engrs 2000; 214: 659−667. 13.

Auswin MK, Ramesh S. Truss access new conservative approach on access opening of a lower molar: a case report. J Adv Pharm Edu Res 2017; 7: 345−348.

14.

Compliance with Ethical Standards

Conflict of Interest: The authors declare that they have no conflict of interest. Informed Consent: Informed consent was obtained from all individual participants included in the article.

Asundi A, Kishen A. Stress distribution in the dento-

Mannan G, Smallwood E, Gulabivala K. Effect of access cavity location and design on degree and distribution of instrumented root canal surface in maxillary anterior teeth. Int Endod J 2001; 34: 176−183.

15.

Krishan R, Paqué F, Ossareh A, Kishen A, Dao T, Friedman S. Impacts of conservative endodontic cavity on root canal instrumentation efficacy

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access and directed dentin conservation. Dent Clin N Am 2010; 54: 249−273. 2.

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Neelakantan P, Khan K, Ng GPH, Yip CY, Zhang

access cavity designs. J Endod 2017; 43: 995−1000.

C, Cheung GSP. Does the orifice-directed dentin conservation access design debride pulp chamber

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human tooth. Int J Oral Sci 2014; 6: 61−69.

molars similar to a traditional access design? 3.

18.

and technological insights: DENTISTRY

invasive access cavity designs. J Eur Ceram Soc 2017;

TODAY; 2017 (cited 3 October 2019). Available

37: 4423−4429. 19.

remaining tooth structure on the fracture resistance

structural-and-technological-insights

of endodontically-treated maxillary premolars: an

Sedgley CM, Messer HH. Are endodontically

in vitro study.

332−335.

J Prosthet Dent 2016; 115: 290−295. 20.

substance on fracture strength of endodontically

2015; 9: 287−288. 21.

treated teeth. J Endod 2018; 44: 1416−1421.

S. Impacts of contracted endodontic cavities on instrumentation efficacy and biomechanical

3 October 2019). Available from: http://www.

responses in maxillary molars. J Endod 2016; 42:

new-access-concept-in-endodontics

8.

1779−1783. 22.

Silva EJNL, Teixeira CS. Influence of access cavity

Practices in Endodontics: A Desk Reference. USA:

design on root canal detection, instrumentation

Quintessence Publishing Co, Incorporated, 2015.

efficacy, and fracture resistance assessed in maxillary molars. J Endod 2017; 43: 1657−1662.

Black GV. Operative Dentistry. Medico-Dental 23.

11.

Sabeti M, Kazem M, Dianat O et al. Impact of access

Trope M, Serota K. Bio-minimalism: Trends and

cavity design and root canal taper on fracture

transitions in endodontics. Provider 2016; 501:

resistance of endodontically treated teeth: an ex vivo investigation. J Endod 2018; 44: 1402−1406.

98−103. 10.

Rover G, Belladonna FG, Bortoluzzi EA, De-Deus G,

Schwartz RS, Canakapalli V, Anthony L. Best

Publishing Co, 1955. 9.

Moore B, Verdelis K, Kishen A, Dao T, Friedman

Belograd M. The genious 2 is coming 2014 (cited dentinaltubules.com/videos/ninja-access-a-

7.

Ahmed HMA. Thoughts on conventional and modern access cavity preparation techniques. Endo

Corsentino G, Pedullà E, Castelli L et al. Influence of access cavity preparation and remaining tooth

6.

Ibrahim AMB, Richards LC, Berekally TL. Effect of

endodontics/10346-endodontic-controversies-

treated teeth more brittle? J Endod 1992; 18: 5.

Chlup Z, Žižka R, Kania J, Přibyl M. Fracture behaviour of teeth with conventional and mini-

Ruddle CJ. Endodontic controversies: Structural

from: https://www.dentistrytoday.com/

4.

Zhang Y-R, Du W, Zhou X-D, Yu H-Y. Review of research on the mechanical properties of the

and mesial root canal systems of mandibular J Endod 2018; 44: 274−279.

Plotino G, Grande NM, Isufi A et al. Fracture strength

Clark D, Khademi JA. Case studies in modern

24.

Özyürek T, Ülker Ö, Demiryürek EÖ, Yılmaz F. The

molar endodontic access and directed dentin

effects of endodontic access cavity preparation

conservation. Dent Clin N Am 2010; 54: 275−289.

design on the fracture strength of endodontically

Asundi A, Kishen A. A strain gauge and

treated teeth: Traditional versus conservative

photoelastic analysis of in vivo strain and in vitro

preparation. J Endod 2018; 44: 800−805.

October 2020

Radiology

Enhanced CPD DO C

Kuljit K Grewal Neil Heath

Update on Ionizing Radiation Regulations 2017 (IRR 2017) and Ionizing Radiation Medical Exposure Regulations 2018 (IRMER 2018) − Relevance to the Dental Team Abstract: The introduction of the new European Basic Safety Standards Directive in 2013 outlined clear responsibilities and requirements for all professionals involved in radiodiagnostic and radiotherapeutic procedures. Its guidance has since been transcended and incorporated into the revised IRR 2017 and IRMER 2018 national guidelines. The revisions to the guidelines have implications for all health professionals involved in undertaking radiation exposures, including dentists, doctors, medical physics staff and radiographers. CPD/Clinical Relevance: Dentists need to appreciate the revisions in IRMER 2018 and IRR 2017 guidance and incorporate these changes into clinical practice to ensure good practice. Dent Update 2020; 47: 755–760

The new European Basic Safety Standards Directive was unanimously adopted in 2013.1 It incorporates recommendations issued by the International Commission on Radiological Protection, as well as

Kuljit K Grewal, BDS, MFDS(Glas), GDP, HHS Dental Practice, Hounslow, (email: [email protected]) and Neil Heath, DCR(R), BDS, MSc(Newc) MFDS(Edin), FDS RCPS(Glas), DDR RCR, Consultant at Newcastle Dental Hospital, Richardson Road, Newcastle upon Tyne NE2 4AZ, UK. October 2020

operational expertise and latest scientific evidence. The directive has since been embedded into UK law by revision of IRMER 2018 and IRR 2017 guidance. The purpose of this article is to shed light on some of the changes introduced and highlight its relevance to the dental team.

IRR 2017 IRR 2017 predominantly focuses on radiation exposure to employees and the public. It is regulated in dental practice by the Health and

Safety Executive (HSE). The revision of the guidelines required all dental practices to register with the HSE, at a fee of £25 by the 5th February 2018, to acknowledge the use of dental X-ray equipment. This is due to the graded approach utilized by HSE, whereby dental radiation exposures are perceived as ‘intermediate risk’. In light of a material change, such as a change of address, it would necessitate the employer to register again.2 Under previous regulations, employers were only obligated to inform the Health and Safety Executive of the use of DentalUpdate 755

Radiology

of 150 mSv. This is due to the increased radiosensitivity of the lens, a caveat to this implementation being the use of dedicated eye dosimeters to measure exposures accurately. These are doses much higher than any dentist should receive. Definition of ‘classified’ and ‘non-classified’ outside workers

Figure 1. The key areas that need to be covered as part of the induction process when new staff are enrolled into the Radiology Department at Newcastle Dental Hospital.

ionizing radiation for dental radiography purposes.

Key changes in IRR 2017 Appointment of Medical Physics Experts (MPE)

IRR 2017 places a clear emphasis on the employer to appoint a competent certified person to fulfil the role of Medical Physics Expert (MPE), a term used in IRMER and/or Radiation Protection Adviser (RPA). It highlights the need for the MPE to meet a set criteria of competence, and actively be involved in assessing patient dose and quality assurance of radiography equipment. Unintended or accidental exposure

In the event of an unintended or accidental exposure, the new guidelines

756 DentalUpdate

stress the need for greater transparency to ensure all parties are informed of the incident and the outcome of analysis of the exposure. Under this legislation and a duty of candour, this is then required to be relayed to the patient. The IRMER practitioner and IRMER referrer must also be informed. The authors of this paper deem a ‘clinically significant’ exposure to be: „ Any over exposure or unintended dose that results in an additional risk to the patient of more than 1 in 1000; „ Any over exposure or unintended dose that is likely to result in a tissue effect (ie skin reddening); „ An exposure which compromises a dose limit set for the lens of the eye. IRR 2017 also states that the dose limit to the exposure of the lens of the eye has been reduced to 20 mSv compared to the previous limit

Furthermore, the revised IRR 2017 makes a differentiation between outside workers, depending on whether they are ‘classified’ or ‘non-classified’. A classified worker being an ‘employee receiving an effective dose greater than 6 mSv a year or an equivalent dose greater than 15 mSv per year for the lens of the eye, who carries out services in a controlled area’. Such a dose should not be experienced by the dental team. A non-classified outside worker is permitted to work and provide services within the controlled area, ‘however would not be exposed to an effective dose greater than 6 mSv a year or an equivalent dose greater than 15 mSv per year for the lens of the eye’. Therefore, these workers may be engineers or contractors, respectively. Now all employees who undertake work in a radiation-controlled area, who are likely to surpass public dose limits, must have radiation monitoring and training. This would not normally include the dental team in their normal role.

IRMER 2018 IRMER 2018 primarily ensures that patients are protected from harm when exposed to ionizing radiation. It applies to all radiation exposures undertaken as part of medical or dental diagnosis, exposures as part of health screening programmes, and those participating in diagnostic or therapeutic research programmes. Its key principles focus on justification of exposures and optimizing diagnostic doses to keep them As Low As Reasonably Practicable (ALARP).

Revisions of IRMER 2018 Carers and comforters

The revision of IRMER makes a clear October 2020

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Radiology

greater emphasis placed on quality assurance programmes and audit to ensure exposure dosages are regularly reviewed and equipment periodically maintained to enhance performance. The requirements differ for CBCT and other dental imaging equipment, and so clinicians must be aware of this.3 Currently, there is uncertainty as to whether exposure dosages used with intra-oral sets need to be clinically documented with every exposure. In standard dental surgery, this may simply involve documentation of exposure factors KVp, mA and time. Many DPT and CBCT machines now give access to/flag up a Dose Reference Level (DRL), which gives a record that can be used by medical physicists. This practice of recording individual exposures would fit with the aspiration to build large datasets, so that national radiation dosages used in dentistry can be harvested for audit. It is the recommendations of these authors that this is best practice. Adequate training for practitioners and operators

Figure 2. The information leaflet available to patients to read in advance of taking the radiograph.

reference to carers and comforters. In the dental environment it would be those willingly and knowingly remaining in the controlled area during the radiation exposure to support the patient, ie a parent with a child. The revision stresses that informed consent must be elicited from the carer in advance, with the net benefit of the October 2020

exposure outweighing any health detriment posed to both the carer and patient. Practically, for the dental team this may involve presenting some dose comparisons to real-life risks. Quality assurance programmes

Another add-on in IRMER 2018 is the

The roles and duties of the IRMER referrer, practitioner and operator remain unchanged. The new revision does stress the necessity for better availability of referral criteria, the use of diagnostic reference levels and encourages better communication between all duty holders. The content of training requirements remains largely unchanged, however, there is an aspiration to educate more in diagnostics, with reference to more emphasis on the fundamentals of radiological interpretation being taught to delegates. Figure 1 demonstrates the key areas that are covered as part of a routine induction to a radiology department. Informed consent

A further change incorporated in the IRMER guidelines states that ‘the employer’s procedures must provide that, where appropriate, written instructions and information are DentalUpdate 759

Radiology

years of leading clinical success c clinica

provided to [the] patient……[and] the individual concerned is informed in advance about the risks of the exposure’.4 How this will be applied to clinical practice is currently under debate. The writers of this paper currently provide patients with written guidance (Figure 2) prior to exposure and acquire verbal informed consent following a brief discussion with the patient. This allows patients to be well versed in the risks and benefits of the exposure, and opens up dialogue for patients to ask questions if any concerns are present. ’Non-medical imaging exposures’ is substituted for ‘medical-legal exposures’

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’Non-medical imaging exposures’ relates to undertaking imaging that is of no health benefit to the individual. In dentistry, this may be for the purpose to age assess specific populations, such as asylum seekers. This is unethical practice, however, but may still be performed by certain public authorities. Other groups who may fall into this category include research subjects and the military. The new revision stresses that employers need to have a set of procedures in place for such requests and appropriate documentation prepared.

Conclusion In conclusion, the revised guidelines changed little, but require more information recording, exchange and justification prior to radiation exposures, especially when carers and comforters are involved. The small amendments are essentially add-ons to encourage further transparency in the event of an accidental exposure, and to ensure good clinical practice. Efficient induction of new staff and follow-up audit continue to underpin these measures. Compliance with Ethical Standards

Conflict of Interest: The authors declare that they have no conflict of interest.

References 1.

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760 DentalUpdate

4.

European Society of Radiology (ESR). Summary of the European Directive 2013/59/Euratom: essentials for health professionals in radiology. Insights Imaging 2015; 6: 411−417. Horner K. Updated: new regulations on xray use − likely implications of IRR17 and IRMER18. Faculty of General Dental Practice (FGDP), 2017 Guidance on the Safe Use of Dental Cone Beam CT (Computed Tomography) Equipment. HPA CRCE 2010. ISBN 970-085951-681-5. Health and Safety. The Ionising Radiation (Medical Exposure) Regulations 2018. Online article available at: https:// assets.publishing.service.gov.uk/government/uploads/ system/uploads/attachment_data/file/627847/ Annex_I_-_Draft_IR_ME_R_2018_Regulations.pdf October 2020

COVID-19Commentary

Enhanced CPD DO C

Lakshman Samaranayake

Niraj Kinariwala

RAPM Perera

Coronavirus Disease 2019 (COVID-19) Diagnostics: a Primer Dent Update 2020; 47: 761–765

The Coronavirus disease 2019 (COVID19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARSCoV-2), seems to have spared no single community. Rapid and accurate identification of COVID-19 patients are the mainstay for breaking the chain of community infection and controlling the pandemic. There are now a bewildering array of diagnostic tests available to detect COVID-19 at various stages of infection. In this, the fourth article in the COVID-19 Commentary series, we describe the basics of current clinical diagnostics, including molecular and serological testing approaches, and summarize their advantages and limitations.

Preamble The current pandemic of COVID-19 is an infectious disease caused by SARS-CoV-2

Lakshman Samaranayake, DDS, FRCPath, FDS RCPS, FDS RCS(Ed), Professor Emeritus, Faculty of Dentistry, The University of Hong Kong, Hong Kong, (email: [email protected]), Niraj Kinariwala, MDS, PhD, Associate Professor, Karnavati School of Dentistry, Karnavati University, Gujarat, India and RAPM Perera, BDS, PhD, Research Assistant Professor, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong. October 2020

which originated in Wuhan, China in late 2019. It is now known that the median incubation period of COVID-19 is approximately 5 days (range: 2 to 14 days), and a large proportion of those infected become symptomatic within two weeks or so (range: 8 to 16 days).1 The recovery period for mild infection is 2 weeks, although in severe cases this may last up to 6 weeks. In the most severe infections, the time from symptom onset to death may range between 2 to 8 weeks, depending on various co-factors, such as the extant co-morbidities. In the early pre-symptomatic phase, the index case unknowingly transmits the infection to others prior to symptom development and, on the contrary, a small proportion of infected individuals never develop symptoms (so called ‘asymptomatics’) and may act as ‘silent spreaders’ of the infection in the community. These two elements of the disease development have made the spread of COVID-19 virtually uncontrollable, leading to the current pandemic. In the absence of efficacious therapeutics and a vaccine, as yet, to combat the infection, the mainstay of prevention and spread of COVID-19 is the early diagnosis of the disease, with the help of an array of diagnostic tests that are currently available. According

to the World Health Organization (WHO) and US Food and Drug Administration (FDA), over 450 tests have been developed thus far for rapid identification of COVID-19 patients in clinical and research settings.2 In order to comprehend the basics of COVID-19 diagnostics, it is essential to know the structural elements of SARS-CoV-2, as the tests are based on the detection of the anatomical components of the organism. Similarly, to understand the serological tests for the virus, a clear comprehension of the host antibody response is essential. These are described first, followed by the diagnostic tests that are in common use.

Anatomy of SARS-CoV-2 (Figure 1) The overall structure of SARS-CoV-2 is similar to other viruses of the Coronaviridae family. It has a protein envelope with characteristic outward projecting spikes (hence the Latin name corona = crown), enclosing a singlestranded, positive sense RNA genome of approximately 30,000 nucleotides in length (Figure 1). The genome is tightly bound to a protein capsid, and both together are called a nucleocapsid. The nucleocapsid is protected by the external protein envelope, which has DentalUpdate 761

COVID-19Commentary

a

b

Figure 1. (a) Morphology of SARS-CoV-2. Transmission electron microscope image of SARS-CoV-2 spherical viral particles emerging from an infected epithelial cell; (b) structural components of SARS-CoV-2. (Modified from the US Centres for Disease Control Image Library).

„ The envelope or E protein, which is the smallest protein in the SARS-CoV-2 structure, plays a role in the production and maturation of this virus.

Serological response (Figure 2)

Figure 2. A diagrammatic representation of antibody development after SARS-CoV-2 infection during the symptomatic period and thereafter (x axis), and the sensitivity for antibody tests (y axis); (RT PCR, real-time reverse transcription polymerase chain reaction; IgM, Immunoglobulin M; IgG Immunoglobulin G). (Note: Antigens can also be detected by RT PCR tests during the pre-symptomatic period which is not shown in the figure).

three major components, the spike (S) glycoprotein, envelope (E) glycoprotein, membrane (M) glycoprotein, (plus several accessory proteins). Thus: „ The nucleocapsid (N) protein cover codes for 27 proteins, including an RNAdependent RNA polymerase; „ The spike or S glycoprotein is a transmembrane protein in the outer portion of the virus and forms, so called,

762 DentalUpdate

homotrimers protruding in the viral surface, giving them the crown or corona-like appearance. They facilitate binding of the virus to the host cells by attaching to the angiotensinconverting enzyme 2 (ACE2) receptors expressed on epithelial and other cells; „ The membrane, or M protein, plays a role in determining the shape of the virus envelope;

In simple terms, the host immune response of the body to SARS-CoV-2 is triggered through the stimulation of the innate immune system cells via antigen presenting cells (eg dendritic cells and macrophages as frontline guardian cells of the host). The antibodies produced are mainly IgM and IgG (together with some IgA), which have a unique profile in response to the infection. The median seroconversion time for IgM and IgG antibodies are 12 and 14 days after the onset of symptoms, respectively, whilst they are detected only in less than 40% of the patients within the first week (Figure 2). In some cases, serum IgG could appear at the same time or even earlier than IgM. It is noteworthy that, in addition to the antibody formation, exposure to coronaviruses in general also induce CD4 T cells and CD8 memory cell development and maturation that can last for up to 4 years. This bodes well for the development of vaccines against SARS-COV-2, as an encounter with the virus even after a few years is likely to protect the vaccinee, after the initial, successful vaccine procedure. October 2020

COVID-19Commentary

Diagnostic tests for COVID-19 (Figure 3; Table 1)

Figure 3. A schematic diagram showing the principles guiding the diagnostic tests for COVID-19.

Type of Test and Synonyms

Primary Clinical Use

COVID-19 diagnostics encompass either: i) Detection of viral antigens which indicate current infection; or ii) The host immune response to the virus (ie specific antibodies) that indicate past infection or vaccination (Figure 3). The following is a primer on the currently prevalent antigen and antibody tests for COVID-19, and their utility. However, it should be noted that, due to the

Specimen/s Required

Turnaround Time*

Properties

I

Viral test, Diagnosis of molecular test, current infection nucleic acid amplification test (NAAT), RT PCR test, LAMP test

Nasal or throat swab (most tests) Saliva (a few tests): respiratory tract specimens in hospitalized patients

May vary from 15 min to 8 hr depending on the type of test, and laboratory workflow

Amplifies viral RNA; Highly sensitive and specific in ideal settings. (Results depend on the type and quality of the specimen and the duration of illness at the time of testing). Usually does not need to be repeated.

II

Antigen tests or rapid diagnostic tests

Diagnosis of current infection

Nasopharyngeal or nasal swabs

Usually less than 60 min

Most probe for nucleocapsid (N) or spike (S) proteins, ie antigens of SARS-CoV-2; generally less sensitive, and more likely to miss an active infection compared to nucleic acid tests.

III

Serology test, Serological test, serology, blood

Diagnosis of prior infection or (in future) seroconversion after vaccination

Finger prick or venepuncture blood

Usually ranges from 15 minutes to 2 hours

Checks for IgG antibodies (mainly) to the S or the spike protein or nucleocapsid, N or NC protein. Highly variable sensitivity and specificity, and hence results should be interpreted with caution; possible cross-reactivity with other coronaviruses reported.

Data from various sources including References 1 and 5; COVID-19: coronavirus disease 2019; RT PCR: real-time reverse transcription polymerase chain reaction; IgG: immunoglobulin G; loop-mediated amplification: LAMP. *Turnaround time is influenced by the test used and laboratory workflow. Note: the sensitivity and specificity of any diagnostic test depend upon the quality of the sample, and various other technical factors. (Note: Antigens can also be detected by RT PCR tests during the pre-symptomatic period which is not shown in the figure) Antigen tests colour coded in green and antibody tests in red. Table 1. Diagnostic tests for COVID-19 and their properties.

764 DentalUpdate

October 2020

COVID-19Commentary

dynamic nature of the subject, the viral testing procedures are in a state of flux. In general, COVID-19 diagnostic tests can be broadly classified as: I. Tests for viral nucleic acid (so called nucleic acid amplification tests or NAATs); II. Tests for viral antigen tests; III. Antibody tests for seroconversion. (Note: A continuously updated infographic on COVID diagnostic tests can be found at https://csb.mgh. harvard.edu/covid) I. Tests for viral nucleic acid (RNA)

Real-time reverse transcription polymerase chain reaction (RT PCR) test is the gold standard for diagnosis of current infection with COVID-19. It amplifies the viral RNA (Figure 1) to detectable levels; hence the term nucleic acid amplification tests (NAAT).3 This method, which is quantitative, and highly sensitive and specific, is also the commonest technique currently used to detect SARS-CoV-2 RNA from respiratory samples. The test is used increasingly on automated platforms, and may take several hours to complete (Table 1). II. Tests for viral antigens

The antigen tests probe for the structural components, such as the nucleocapsid (N) or spike (S) proteins of SARS-CoV-2 (Figure 1) via lateral flow or ELISA (enzymelinked immunosorbent assay) tests, and can be performed with only nasopharyngeal swabs. As these tests take less than an hour to complete, and yield faster results than some NAATs, they are used for point of care (POC) testing (eg airports for arrivals and departures). However, the broad consensus is that the viral antigen tests are less sensitive than NAATs, described in Table 1, and often yield falsenegative results. Hence, a negative antigen test does not necessarily rule out SARS-CoV-2 infection, and should be confirmed using a sensitive NAAT if the clinical suspicion is high. Nevertheless, antigen tests are October 2020

valuable for detecting those in the early stages of infection, when virus replication is at its highest.

COVID-19, including sample collection, transportation and so on, that are not described here, and are beyond the remit of this article.

III. Serological tests

In general, serological tests are useful to determine prior viral exposure of an individual and seroconversion after a course of vaccination (eg akin to seroconversion after Hepatitis B infection or vaccination). They could also be used for retrospective assessment of the efficacy of infection control and lockdown measures, as well as for ascertaining the extent of COVID-19 in the community through en masse evaluation. As soon as any virus infects a person, he/she will start developing antibodies, and the first such antibody type is IgM immediately followed by IgG. The former is rather transient compared to IgG, which could last for several months or years, depending on various factors. This is also the case with SARSCoV-2 infection as, in many studies, IgM and IgG seroconversion occurred in all patients between the third and fourth week. Thereafter IgM began to wane, and virtually disappeared by week 7, although IgG levels persisted beyond 7 weeks.4 As seen above, SARS-CoV-2 possesses various antigenic structural components (Figure 2), and a substantial antibody response is directed against the nucleocapsid (N or NC) protein. Hence, tests that detect antibodies to NC are the most sensitive, though they may be lacking in specificity. However, antibodies to the S or the spike protein are much more specific than that for the NC protein. Additionally, antibodies to the S protein are considered to neutralize the viral infectivity much more than the other antibodies. The long-term persistence of protection conferred by the neutralizing antibodies is unknown, as yet. Finally, serological tests for SARS-CoV-2 should be specific and must differentiate past infections from those caused by other human coronavirus infections (eg SARS-CoV, HKU1). There are also many confounding factors that interfere with laboratory testing for

Future perspectives and conclusions Several simple, reliable and rapid COVID19 diagnostic tests, which could be used at community level and obviate sample referral to a centralized laboratory and consequent prolonged turnaround time, are currently under development. They include loop-mediated amplification (LAMP), recombinase polymerase amplification (RPA) and nicking enzyme-assisted reaction (NEAR) technologies that yield results within 15 to 30 minutes. It is hoped that, in the fullness of time, such miniaturized tests, akin to ‘pregnancy tests’, could be used and interpreted by ordinary citizens at home. These rapid diagnostic tests hold much promise and would be a valuable and welcome addition to curb the pandemic, particularly in resource-poor settings in the developing world where its rabid and rampant spread has created unprecedented suffering, misery and privation.

References 1.

2. 3.

4.

5.

Lee RWH, Ko J, Mikael J, Pittet MJ. COVID-19 diagnostics in context. Sci Transl Med 2020; 12: eabc1931 doi: 10.1126/scitranslmed.abc1931. COVID-19 diagnostic tests. https://csb. mgh.harvard.edu/covid Li CX, Zhao C, Bao J, Tang B, Wang Y, Gu B. Laboratory diagnosis of coronavirus disease-2019 (COVID-19). Clin Chim Acta 2020; 510: 35−46. Sethuraman N, Sundararj SJ, Ryo A. Interpreting diagnostic tests for SARS-CoV-2. J Am Med Assoc 2020; 323: 2249−2251. doi:10.1001/ jama.2020.8259. Cheng MP, Papenburg J, Desjardins M et al. Diagnostic testing for severe acute respiratory syndrome-related coronavirus 2: a narrative review. Ann Intern Med 2020; 172: 726−734.

See review of SDCEP document ’Breaking News: COVID-19 and Dentistry‘ at the end of the Letters to The Editor on page 769. DentalUpdate 765

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we protect lives worldwide *German working group for hygiene in dentistry

Letters

Letters to the Editor COVID-19 mitigation is a barrier to meeting population oral health needs The COVID-19 pandemic has caused substantial disruptions to dental services globally. In the United Kingdom, National Health Service (NHS) dentistry was reduced to telephone consultations with Urgent Dental Care Centres established to deliver emergency dentistry, when deemed necessary, based on a national triaging system. Following lifting of lockdown restrictions, numerous countries released guidance for re-opening and re-structuring dental services to mitigate the risk of SARS-CoV-2 transmission.1 Such risks are of concern in dental clinics due to the high volume of patients, close physical proximity of dental professionals to patients, and aerosol generating procedures (AGPs). SARS-CoV-2 has high affinity to angiotensin-converting enzyme 2, distributed throughout the respiratory tract and present in the oral mucosa. The virus has been isolated in saliva and in the pharynx,2 hence dental AGPs are stratified as high-risk procedures. The current evidence shows that SARSCoV-2 can remain viable in an aerosol for up to three hours.3 Therefore, a ‘fallow’ period is required for the aerosol to settle after an AGP, and is necessary to prevent infection transmission, but limits the number of patients that can be seen. However, there is considerable heterogeneity in the interpretation of the limited available evidence with respect to risk mitigation strategies (eg the use of rubber dam, high volume aspiration, room ventilation, etc), with countries issuing guidance of different fallow times (ranging from 2−180 minutes)1 to their dental workforce. There are substantial challenges in meeting population oral health needs if dental services are limited by a fallow period and, in many instances, dental clinics may become financially unviable to maintain. The risk of live SARS-CoV-2 remaining suspended in the air should not be underestimated. Nevertheless, evidence-based consensus October 2020

is required on ventilation parameters and the most effective risk reduction strategies to enable safe resumption of dental care. Ideally, a rapid SARS-CoV-2 test would provide reassurances for dental professionals to reduce their fallow period and adopt routine personal protective equipment (PPE). This can increase patient capacity and reduce the burden of limited PPE, but would involve testing every patient before each appointment. Multi-faceted infection prevention and control interventions, including hand hygiene and the right level of PPE, remain the most effective methods to prevent infection transmission. The COVID-19 mitigation policies of time restrictions between patients and enhanced PPE, with their surplus costs, strongly suggests that the current commissioning of NHS dentistry requires major reforms to prevent collapse of an integral component of population healthcare. It is expected that rapid SARS-CoV-2 testing will be available in the future, however until then, prolonged disruptions to dental services is likely to have a detrimental effect on patient health. A pragmatic and balanced approach to dental public health reforms is needed, as is urgent research on risk reduction strategies for SARS-CoV-2 in aerosols. Declaration of interests

All authors declare no competing interests.

References 1.

Clarkson JE, Ramsay C, Aceves M, Brazzelli M, Dave M, Glenny AM et al. Recommendations for the re-opening of dental services: a rapid review of international sources. 2020. Cochrane Oral Health (Accessed 25 August 2020]. https:// oralhealth.cochrane.org/news/ recommendations-re-openingdental-services-rapid-reviewinternational-sources

2.

To KK, Tsang OT, Leung WS, Tam AR, Wu TC, Lung DC et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by sars-cov-2: an observational cohort study. Lancet Infect Dis 2020; 20: 565−574. 3. van Doremalen N, Bushmaker T, Morris DH, Holbrook MG, Gamble A, Williamson BN et al. Aerosol and surface stability of sars-cov-2 as compared with sars-cov-1. N Engl J Med 2020; 382: 1564−1567. Manas Dave, NIHR Academic Clinical Fellow in Oral and Maxillofacial Pathology, University of Manchester Noha Seoudi, Senior Clinical Lecturer in Oral Microbiology, Queen Mary University, London Paul Coulthard, Dean for Dentistry and Institute Director, Queen Mary University, London

The Effect of COVID-19 on dental foundation training applications COVID-19 in dental school

The COVID-19 pandemic has altered several features in the practice of dentistry globally, including dental education. Most UK-based dental schools have been closed for at least 6 months and will be operating at a lower capacity once they re-open. Dental schools have been working diligently to establish protocols to ensure that the dental team and patients are in a safe environment. This includes wearing robust PPE, limiting the number of attending patients and one-way walking systems. Students will also be fit-tested for masks before performing aerosol producing procedures. Furthermore, there is likely to be an increase in simulation teaching, such as phantom head work and using virtual reality technology. Dental foundation training application alterations

In June, it was announced that, in light of COVID-19, the dental foundation training DentalUpdate 767

Letters

(DFT) application process would be altered. Whilst previously the ranking for DFT placements was based on faceto-face assessment centre interviews and a situational judgement test (SJT), it will now be based solely on the SJT in order to reduce social contact during interviews. Naturally, applicants are under an increased amount of pressure, given that they will no longer have an interview to support their application or an outlet to present their personalities and enthusiasm to potential trainers. Expectation for the future

Despite the efforts made by universities to continue teaching during the pandemic, students will be graduating having partaken in less clinical time at university. Furthermore, in the event of a second wave of the virus, there are likely to be further disruptions. Due to the lack of clinical time, it is probable that newly qualified dentists will require more support from their dental trainers. In addition, with video and phone consultations becoming more routine, learning to conduct these effectively may become essential to training. With diligent planning and preparation, there is hope that the next cohort of dental foundation trainees will also have a constructive training experience and ultimately be able to provide optimal care to their patients. Ayla Mahmud, Biomedical Science BSc(Hons) BDS5 Student at King’s College London

COVID-19 educational resource COVID has had an unsettling impact on dental education. The team at revisedental.com have produced an evidence-based educational resource, providing the student and young professional with a ‘go to’, reliable platform that helps guide self-directed learning. Moreover, the site donates all its contributions, supporting: the BDA Benevolent Fund and the Motor Neurone Disease Association. The site has attracted a vast amount of specialist help, supporting the growth of the premium content;

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advancing student learning. This area continues to expand and, if you wish to help and support, please don’t hesitate to contact the team. The impact of the site so far has received wonderful feedback, with numerous students already visiting and interacting with the content. The site also offers student collaborations, through interprofessional teamwork, which is essential during these times more than ever. The team has brought together medics, pharmacists and other dental professionals. This has been on both a national and an international scale (eg Australia), boosting the quality of the lesson content. In addition to the charitable donations and the site itself, the team’s efficiency, motivation and dedication to producing the wonderful content has been incredible. Each member brings his/ her unique attributes, all with the aim to help colleagues, both during these strange times, and for the future. We hope you enjoy visiting www.revisedental.com Now is the time to pull together and support our own education, going forward, to adapt for the new normal. Mike Daldry, Sumeet Sandhu, Leah Webb and Jaimi Shah

Time to rethink, reconsider and reinvite case reports! We, as clinicians come across interesting, or challenging clinical cases in our everyday practice. Few of these cases stand apart, as they may be combined with an interesting observation, a rare clinical sign, unexplored association of various clinical manifestations, etc.1 Unfortunately, case reports are not being accepted by many reputed journals and are tagged as the lowest level of research.2 Many journals flatly refuse to accept case reports and consider them as beyond the scope of publishing. Sadly, some journals, which do accept them, quote exorbitant article processing charges, which demotivates the authors further. Most indexed journals do not support publishing case reports, which has paved the way for predatory and dubious journals to fill this void, publishing case reports while charging

the fees. This is one of the known barriers, preventing competent clinicians from sharing their experiences in the form of case reports and series. The current medical literature primarily focuses on evidence-based practice which has led to the notable decline in the publishing of clinical case reports,2 possibly due to the inability of scrutinizing the originality of the case, with an inherent risk of fraudulent information being incorporated to make it more appealing. Furthermore, the lesser number of citations received for case reports compared to original research, metaanalysis and reviews, which indirectly hampers the overall journal performance assessment and impact factor, further discourages the publishing of case reports.3 Case reports can still serve as a useful platform to share our unique and interesting experiences and to reinforce certain overlooked clinical diagnostic clues. They serve as teaching aids for educating healthcare students.4 Moreover, the novel management strategies or follow-up protocols adopted in specific disorders, and its response, could help us to think beyond the traditional options and seed research ideas. Thus, case reports contribute to a modest but significant role in knowledge dissemination. To ensure completeness and transparency of published case reports, a consensus-based clinical case reporting guideline, termed ‘CARE’ (CAse REport) has been formulated.1 A CARE guidelines checklist helps the author to document the clinical case reports accurately and this checklist has become an integral part of the manuscript submission platform in recognized journals. On the other hand, PROCESS (Preferred Reporting Of CasE Series in Surgery) guidelines are recommended while documenting surgical case reports, and this has improved reporting transparency of case series across several surgical specialties.5 It is time to realize that case reports contain a small but significant piece of disrupted information, unlike original research articles, which may have technical and processing errors inherent to the study design. However, shouldn’t we reconsider and reinvite case reports and October 2020

Letters

recognize their duly deserved position in the medical literature? In the mad rush to compete with journal ratings, citations and impact factors, etc, are we ignoring the reader’s choices?

2.

3.

References 1.

Gagnier JJ, Kienle G, Altman DG, Moher D, Sox H, Riley D, CARE Group. The CARE guidelines: consensusbased clinical case reporting guideline development. J Med Case Rep 2013; 7: 223.

Breaking News: COVID-19 and Dentistry Mitigation of Aerosol Generating Procedures in Dentistry – A Rapid Review by the Scottish Dental Clinical Effectiveness Programme (SDCEP): An Appraisal It had the makings of a perfect storm! A vicious virus infecting through aerosol transmission, and a livelihood necessitating aerosol generating procedures (AGPs). This epitomizes the predicament of returning to dental practice in the Coronavirus Disease 2019 (COVID-19) pandemic era. Eight months into the pandemic, various bodies have issued multiple recommendations on how best to mitigate AGPs in routine dentistry,1 but most are not evidencebased and are unsubstantiated, probably due to the dearth of data on SARS-CoV-2 and its spread. Hence, it is gratifying to note the arrival of a brand new document from the Scottish Dental Clinical Effectiveness Programme (SDCEP) entitled Mitigation of Aerosol Generating Procedures in Dentistry – A Rapid Review,2 sponsored by NHS Education, Scotland. Chaired by Professor Jeremy Bagg, and an erudite group of academics, clinicians and a member of the public have produced this timely document (46 pages) identifying and appraising the extant evidence on a number of key questions related to AGPs in dentistry, and recommending mitigation measures. In the preamble, the authors categorically state that the review and the conclusions do not have the status October 2020

4.

Pimlott N. Two cheers for case reports. Can Fam Physician 2014; 60: 966–967. Available from: http:// www.cfp.ca/content/60/11/966. long Kidd MR, Saltman DC. Case reports at the vanguard of 21st century medicine. J Med Case Rep 2012; 6: 156. Yitschaky O, Yitschaky M, Zadik Y. Case report on trial: Do you, Doctor, swear to tell the truth, the whole truth and nothing but the truth? J Med Case Rep 2011; 5: 179.

of guidance, and should primarily be used to inform policy-making, and developing clinical guidance relevant to dental care delivery during the COVID19 pandemic. This is a sensible stance as the data on SARS CoV-2 and the spread of infection are constantly emerging. The document focuses on three main areas, ie AGPs, procedural mitigation and environmental mitigation. These are then subdivided as, categorization of AGPs, high volume suction, rubber dam isolation, preprocedural mouthrinses, antimicrobial coolants, ventilation and air-cleaners. Then, each of the sub-sections are further discussed in terms of: i) evidence summary and appraisal; ii) considered judgement and agreed position; and iii) agreed position statement. Thus, in total there are well argued and articulated, six position statements for the foregoing subcategories. The document ends with a succinct section on implications for clinical practice, and research considerations. On the whole, the clarity of the document must be commended. Some of the traditionally recommended infection control measures, such as the preprocedural antiseptic mouthwashes, are discouraged, and I fully concur with this view of a ritualistic practice that has a flimsy evidence base, in terms of combating infection transmission in the clinical environment. I also believe the categorization of AGPs into three groups, according to the uses of high (a) and low (b) powered instrumentation,

5.

Agha RA, Borrelli MR, Farwana R, Koshy K, Fowler AJ, Orgill DP, et al. The PROCESS 2018 statement : Updating Consensus Preferred Reporting Of CasE Series in Surgery (PROCESS) guidelines. Int J Surg 2019; 60: 279–282. Mathangi Kumar Shruthi Acharya Ravindranath Vineetha Department of Oral Medicine and Radiology, Manipal College of Dental Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India

and (c) no powered instrumentation, is sensible, simple and practical, as dentists can formulate the mitigation measures accordingly. One statement that I personally do not concur with is the division of fallow periods into five different time periods of 5 min intervals, as dictated by the use of AGPs. I wonder whether this is a practical proposition. The latter, however, is a minor blemish in an otherwise insightful and instructive review on AGPs in dental practice. Professor Bagg and his team should be applauded for producing such an important, comprehensive and a timely commentary when the pandemic is waning in most countries, and return to routine clinical dentistry is a feasible proposition. I have no hesitation in commending this freely available review as essential reading to all practitioners. Note: Any further discussion of the review will appear in the November 2020 issue of Dental Update.

References 1.

2.

Jamal M, Shah M, Almarzooqi SH, Samaranayake LP et al. Overview of transnational recommendations for COVID‐19 transmission control in dental care settings. Oral Dis 2020. Available at: https://doi.org/10.1111/ odi.13431 https://www.sdcep.org.uk/ wp-content/uploads/2020/09/ SDCEP-Mitigation-of-AGPS-inDentistry-Rapid-Review.pdf Lakshman Samaranayake Professor Emeritus, University of Hong Kong DentalUpdate 769

ClinicalExperiencesofReaders

'I learnt about Dentistry from that' Readers are encouraged to submit clinical experiences, good and bad, in a culture of open reporting, so that other clinicians will learn from these experiences. Unlike articles in Dental Update, in which published articles are peer reviewed by two experts in the field of the article, this page is not subjected to review other than by the Editorial Director.

When I was a newly qualified dentist, an older gentleman attended for his 6-monthly routine dental check-up. He had no complaints. He lay back in the chair and I began the check-up. He had an upper denture in place and asked if I would like him to remove this. ‘Yes please’, I replied. Out the denture came. I began to examine him again and was immediately worried. On the buccal aspect of the maxillary alveolar ridge was a poorly defined patch of erythema with several white speckles overlying it, which had previously been hidden by his denture. Thinking back to my oral medicine lectures, I knew that a white and red patch, in an older patient, who also smoked, was bad news. I asked the patient if he was aware of the patch or it had given him any symptoms; ‘I didn’t know there was anything there at all’, he replied. ‘Painless’ I thought – another bad sign. I called a (very busy) senior associate dentist to come and have a look. When he arrived (mid-extraction with his own patient), I tried to convey my concern to him in ‘dental code’ and with my worried facial expression. He sat down and looked at the patch. He then wiped it clean off with a glove, revealing totally normal mucosa beneath. He examined the red debris that had come away on his glove. ‘That’s a bit of old mouldy cherry tomato skin that’s been sitting beneath the denture’, he explained. The patient then recalled the last time he ate cherry tomatoes (a full week ago) and, needless to say, I went the colour of the cherry tomato. I learnt always ‘to get stuck in’ when examining mucosal abnormalities, something which is now the bread and butter of my job in oral medicine. Don’t be scared by a mucosal abnormality – touch it, feel it, see if it rubs off! These are all essential for a provisional diagnosis!

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18/06/2020 16:55

October 2020

TechniqueTips

Technique Tips The Role of Fibre-reinforced Composite Posts in Children This technique tip highlights the role of fibre-reinforced composite (FRC) posts in managing fractured teeth, as well as their specific application in children, with a casebased discussion and exploration of their advantages and disadvantages. Dentists are frequently exposed to the management of fractured anterior teeth in children. Restoring extensively fractured permanent teeth in a child to maintain function and aesthetics can pose a significant clinical challenge. Conventional techniques to support coronal restorations of teeth with little supragingival tooth structure in children may not always be practicable. They may not conform to immature canal anatomy or may require an indirect restoration with laboratory input, which may necessitate multiple appointments. In a growing child, FRC may provide a useful alternative to address the shortcomings of more traditional restorative techniques in restoring an extensively fractured anterior tooth. The everStick® POST (GC Europe NV, Leuven, Belgium) (Figures 1−3), a silanated E-glass fibre impregnated with a bis-GMA matrix and Polymethylmethacrylate (PMMA) polymer,1,2 is an example of such an alternative. It is an adaptable, soft and flexible post with a diameter of approximately 1.5 mm and similar composition to composite. The term ‘E-glass’ refers to fibres which are a variant of a FRC which has been found to have superior strength properties in varying conditions, good chemical resistance and sufficient imperviousness to moisture.3,4 Whilst we are focusing on its use as a post in a fractured anterior permanent central incisor, other uses of variants of everStick® POST (GC Europe NV, Leuven, Belgium) include a splinting material for periodontally compromised teeth or a minimally invasive composite bridge, which are discussed in greater detail in other literature.5,6 In using this type of post, it

allows for less invasive canal preparation, helping to maintain dentine and reduce the likelihood of iatrogenic damage to the tooth, such as perforations. In paediatric patients, traumatized teeth can require operative treatment at an early age and may require further treatment in the future. This proved to be a useful choice for re-restoring a heavily fractured tooth with a guarded clinical prognosis. A low viscosity cement helps to ensure that the post can reach the full anatomy of the root canal, preventing voids and unpolymerized areas for leakage and a poor overall seal.7 Further advantages and disadvantages are summarized in Table 1. The use of everStick® POST (GC Europe NV, Leuven, Belgium), as a post to aid in the restoration of an UR1 in a child which had a history of a complicated crown fracture and previous failed root canal treatment with post, core and crown is highlighted.

Case report A nine-year-old boy was seen in the Paediatric Dental Department at Birmingham Dental Hospital for assessment of his UR1, which was causing him pain. On presentation, the UR1 had a buccal sinus and mobile indirect crown. The UR1 had previously sustained a complicated crown fracture, which had been treated with root canal treatment and a metal post, core and crown. A pre-operative radiograph was taken of the UR1 revealing an open apex, suboptimal RCT and poorly fitting post, core and crown (Figure 4). On removal of the restoration under dry dam and local anaesthetic, it was noted that there was a lack of coronal supragingival tooth structure. Following removal of GP using Hedstrom files, the UR1 underwent re-root canal treatment (Figure 5) and was dressed with calcium

Figure 1. everStick® POST (GC Europe NV, Leuven, Belgium) packet.

Figure 2. everStick® POST (GC Europe NV, Leuven, Belgium) encased within silicone, where it can be cut to the appropriate length.

Figure 3. Handling of everStick® POST (GC Europe NV, Leuven, Belgium) with tweezers, for placement into root canal. Multiple posts can be used, if necessary, depending on morphology.

hydroxide and temporized with composite. Four weeks later, symptoms improved and the patient returned for removal of the

Amardeep Singh Dhadwal, BDS, MFDS RCPS(Glasg), Academic DCT, (email: [email protected]), Sarah J McKaig, BChD, FDS RCS(Ed), MPaedDent(Glasg), FDS(PaedDent) RCS(Ed), Consultant in Paediatric Dentistry and Abdullah Casaus, BDS, MJDF RCS(Eng), MPaedDent RCS(Eng), FDS(PaedDent) RCS(Eng), Consultant in Paediatric Dentistry, Birmingham Dental Hospital and School of Dentistry, Birmingham Community Healthcare NHS Foundation Trust, Birmingham, UK. October 2020

DentalUpdate 771

TechniqueTips

Advantages

Disadvantages

Improved aesthetics and shade to tooth colour

Canal preparation and dentine removal still required

Good flexibility, facilitating negotiation around curved canals, immature canal anatomy and larger canals

Radiolucent and reduced visibility on radiographs

Chairside fabrication and adjustments: can be adjusted for size through cutting and/or adding more posts to the canal based on anatomy and size

Technique sensitive − clinicians may find them difficult to handle and manipulate with tweezers

Ability to bond directly to composite

Still reliant on the child’s co-operation and the ability of the child to tolerate root canal treatment and tooth isolation

Figure 6. Labial view of UR1 after re-root canal treatment had been undertaken showing a lack of supragingival tooth structure labially.

Similar modulus of elasticity to dentine8 Table 1. A table to summarize the advantages and disadvantages of FRC posts in paediatric patients.

Figure 7. UR1 with FRC post in situ, rubber dam and OpalDam (Ultradent Products Inc, South Jordan, USA) used for moisture control.

Figure 4. Pre-operative periapical radiograph of UR1 highlighting a suboptimal root canal treatment with extrusion of GP, poorly fitting post, core and crown and associated apical area.

temporary restoration and obturation with Mineral Trioxide Aggregate (MTA). Due to the lack of remaining supragingival tooth structure remaining (Figure 6), retraction cord with astringent was used to isolate the margins and a FRC post everStick® POST (GC Europe NV, Leuven, Belgium) was used (Figures 7 and 8), which was cemented using a low-viscosity dual curing resin cement (GRADIA®, GC). Finally, the

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Figure 5. Mid-treatment radiograph, highlighting re-established working length following canal re-preparation.

Figure 8. Close-up image of UR1 with FRC post in situ, rubber dam andOpalDam (Ultradent Products Inc, South Jordan, USA) used for moisture control.

tooth was restored using direct composite. Occlusion was checked prior to completion (Figure 9). A post-operative radiograph revealed a well-condensed post, following the patient’s root canal anatomy (Figure 10).

permanent teeth in children due to insufficient supragingival tooth structure and large root canal anatomy. The use of FRC posts can provide an alternative, chairside solution to restore a child’s dental function and aesthetics in these cases.

Conclusion

Conflict of interest

Dentists may encounter difficulties in restoring severely fractured anterior

The authors declare that they have no conflict of interest or any support from the October 2020

TechniqueTips

3.

4.

5.

6. Figure 9. Post-operative labial view of UR1 post finishing and placement of final composite restoration.

7. manufacturers of any items discussed.

References 1.

2.

Figure 10. Post-operative radiograph, highlighting a well-condensed post and a good apical and coronal seal.

Özcan M, Kumbuloglu O. Fracture strength of fiber-reinforced surfaceretained anterior cantilever restorations. Int J Prosthodont 2008; 21: 228−232. Vallittu PK, Sevelius C. Resin-bonded,

glass fiber-reinforced composite fixed partial dentures: a clinical study. J Prosthet Dent 2000; 84: 413−418.

8.

Zhang M, Matinlinna JP. E-glass fiber reinforced composites in dental applications. Silicon 2012; 4: 73−78. Nayar S, Ganesh R, Santhosh S. Fiber reinforced composites in prosthodontics − a systematic review. J Pharm Bioallied Sci 2015; 7(Suppl 1): S220−S222. Van Rensburg J. Fibre-reinforced composite (FRC) bridge − a minimally destructive approach. Dent Update 2015; 42: 360−366. Van Rensburg J. Fibre-reinforced composite splint − step-by-step instructions. Dent Update 2019; 46: 380−387. Aksornmuang J, Nakajima M, Tagami J. Effect of viscosity of dual-cure luting resin composite core materials on bond strength to fiber posts with various surface treatments. J Dent Sci 2014; 9: 320−327. Plotino G, Grande NM, Bedini R, Pameijer CH, Somma F. Flexural properties of endodontic posts and human root dentin. Dent Mat J 2007; 23: 1129−1135.

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DentalUpdate 773 28/07/2020 10:59

CPD continuing education Test your knowledge on the content of the articles published. The following 10 questions relate to some of the articles carried this month. Only one answer is correct. To receive CPD credit answer the questions online at www.dental-update.co.uk

Q1

AYUB, KHAN AND KELLEHER 47: 706–712

Regarding dens evaginatus (DE): A. There is only one classification for this. B. Pulp tissue is never found within the tubercle associated with this. C. This is never associated with shovel-shaped incisors with prominent marginal ridges. D. This occurs more frequently in the mandible than the maxilla.

Q2

AYUB, KHAN AND KELLEHER 47: 706–712

Regarding prevalence of DE: A. This never occurs bilaterally. B. It is seen more frequently in Asian patients. C. Upper incisors are more frequently affected than premolars. D. Patients with SturgeWeber syndrome are at a lower risk of having DE.

Q3

OWEN ET AL 47: 714–718

Regarding coronectomy: A: Re-operation rates are 15%. B: Case selection is limited to vital teeth with a high risk of IANI. C: CBCT is of no help in cases requiring coronectomy. D: Piezosurgery is of no value in coronectomy cases.

Q4

O’LEARY AND GUNDERMAN 47: 719−727

Regarding chairside digitization: A. There are no challenges when trying to obtain accurate cross-arch dental prostheses. B. The potential for gag-reflex activation is increased by using this. C. The main advantage is improved patient comfort. D. Set-up costs are low and therefore not a barrier.

Q5

O’LEARY AND GUNDERMAN 47: 719−727

Regarding gag reflex: A. Patients with a severe gag reflex never vomit during impressiontaking. B. Jackson and Jones produced an index for its severity. C. Using intra-oral scanners rather than conventional impressioning may reduce the potential for gag-reflex activation. D. Gagging is always caused by a mental trigger. DEADLINE FOR SUBMISSION: 14 DECEMBER 2020 10 QUESTIONS REPRESENT 4 HOURS OF CPD ANSWERS FOR JULY/AUGUST CPD ON PAGE 746

CPD in Dental Update in partnership with

774 DentalUpdate

Q6

MEADE 47: 729–738

Regarding supernumerary teeth: A. Their aetiology is well understood. B. Prevalence has been reported to be greater among African Americans. C. Males appear to be less likely than females to present with a supernumerary in the permanent dentition. D. These never need to be removed.

Q7

MEADE 47: 729–738

Regarding clinical characteristics of supernumerary teeth: A. Dentigerous cyst formation is never a complication associated with a supernumerary tooth. B. Delayed eruption of associated teeth has been reported in up to 60% of Caucasians with supernumerary teeth. C. These never cause failure of eruption of a permanent maxillary incisor. D. Migration of the supernumerary into the nasal cavity is common.

Q8

NOORANI ET AL 47: 747–754

Regarding RCT access cavity preparation: A. The least important tooth structure responsible for long-term survival is considered to be the pericervical dentine. B. Complete removal of caries is not necessary. C. An important reason to eliminate undermined and unsupported tooth structure is to evaluate whether the tooth is restorable or not. D. There is very good evidence to suggest that conservative or ultraconservative access cavity design can help retain endodontically treated teeth for longer.

Q9

GREWAL AND HEATH 47: 755–760

A ‘clinically significant’ exposure is considered to be: A. Any over exposure/unintended dose that results in an additional risk to the patient of more than 1 in 10. B. Any over exposure/unintended dose that results in an additional risk to the patient of more than 1 in 500. C. Any over exposure/unintended dose that results in an additional risk to the patient of more than 1 in 1000. D. Any over exposure/unintended dose that results in an additional risk to the patient of more than 1 in 10,000.

Q10 GREWAL AND HEATH 47: 755–760 Revisions to IRMER 2018: A. Incorporate voluminous amendments. B. Include the text ‘… written instructions and information are provided to the patient and the individual concerned is informed in advance about the risks of the exposure’. C. Quality assurance programmes and audit to record exposure dosages are no longer needed. D. Regular maintenance of equipment to enhance performance is not needed.

October 2020

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1. Barnett ML. The rationale for the daily use of an antimicrobial mouthrinse. JADA 2006; 137: 16S-21S 2. Araujo MWB et al. Meta-analysis of the effect of an essential oil-containing mouthrinse on gingivitis and plaque. JADA 2015; 146(8): 610-622 UK/LI/20-15605