The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study PROTOCOL
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Table of contents TABLE OF CONTENTS ................................................................................................................. 1 1. GLOSSARY .......................................................................................................................... 2 2. INTRODUCTION ................................................................................................................ 2 3. AIMS OF THE STUDY ......................................................................................................... 3 3.1. PRINCIPAL AIM ................................................................................................................. 3 3.2. SECONDARY AIM .............................................................................................................. 4 4. EXPERIMENTAL DESIGN AND METHODOLOGY .................................................... 4 4.1. TYPE OF STUDY .................................................................................................................. 4 4.2. SELECTION OF GENERAL DENTISTS........................................................................... 5 4.3. SELECTION OF PATIENTS .............................................................................................. 5 4.4. NUMBER OF SUBJECTS NECESSARY ........................................................................... 5 4.5. SAMPLING METHODS ....................................................................................................... 5 4.6. CALIBRATON OF EXAMINERS ........................................................................ 5 5. INFORMATION TO BE COLLECTED ............................................................................. 6 6. ORIGIN AND TYPE OF CATEGORICAL DATA TO BE COLLECTED .................... 6 6.1. DOCUMENTS TO BE COMPLETED ............................................................................... 6 7. DATA MANAGEMENT ....................................................................................................... 7 7.1. STATISTICAL ANALYSIS ................................................................................................ 7 8. ETHICAL CONSIDERATIONS ......................................................................................... 8 9. BUDGET ................................................................................................................................. 9 10. TIMETABLE.......................................................................................................................... 9 11. SCIENTIFIC COUNCIL ...................................................................................................... 9 12. NATIONAL INSTITUTIONS…………………………………………………………..… .9 12. REFERENCES …………………… ...................... ……………………………………..….10
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
1. Glossary BEWE GDP SD BU NCCL OR
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Basic Erosive Wear Examination General Dental Practitioners “Sentinel” Dentist Bristol University Non-Carious Dental Cervical Lesion Odds ratio
2. Introduction All teeth are exposed to attrition by virtue of being in an environment which wears the teeth and may result in cervical wear lesions. To different degrees, all dental surfaces are at risk of wear due to conditions inherent in the oral environment, and it is generally agreed that their aetiology is multifactorial. Different cervical lesion morphologies have been described corresponding to particular principal or even sole causes, so that cervical lesions may be identified and quantified in epidemiological studies. Non-carious cervical lesions progress constantly. Their high prevalence may be attributed to several factors of which the most important are linked to oral hygiene practices and dietary habits; to these may be added stress and its effects on the occlusion, and increases in population longevity. Cervical wear lesions typically present for one of three reasons. The patient may well present spontaneously because of hypersensitivity associated with the lesion or because of unaesthetic appearance, or the condition may be detected at a routine dental examination, without the patient being aware of a problem. Clinical identification of the lesion will determine the diagnosis and govern the therapeutic decision. Identification of aetiological factors will determine the prognosis of the lesion and suggest the treatment plan. The latter should most definitely include preventing the aggravation of the symptoms and the lesions, to facilitate the ultimate success of any restorative treatment. Non-carious cervical lesions are generally linked to a combination of three basic mechanisms: • Mechanical Mechanisms: Abrasion of enamel, due to forceful brushing. This well recognised mechanism may be accompanied by superficial gingival inflammation and gingival recession. Mechanical mechanisms underlie also the loss of tissue due to flexion of the dental crown under mechanical masticatory forces. Repeated flexion may lead to localised sub-surface tissue loss as pieces of the tissue fracture off. Details of this mechanism for tissue loss remain controversial. • Chemical mechanisms: Erosion of dental calcified tissue under the influence of acids can occur; the acids may be of dietary origin, or come from pharmaceutical products, or be linked to certain work environments. Gastroesophageal reflux, which may affect up to 60% of people during their lives, may also lead to erosions. The multifactorial origin of these lesions makes it difficult to define exactly their aetiology. The difficulty may be explained partly by the very wide differences in prevalence reported by different studies. Today, it is nevertheless possible to narrow down the aetiology of non-carious cervical lesions by identifying and analysing certain potential causal factors. These determining factors may be gleaned from: - Questionnaires competed by affected persons covering hygiene habits, dietary habits and any pathology or medication that could modify the pH of the oral environment or affect the buffering capacity of saliva. - Clinical records which provide information from ordinal indices on tooth wear, periodontal health and the occlusion.
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
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Few representative studies have examined the relationship between non-carious cervical lesions and periodontal disease in subjects presenting with clinical loss of attachment. An observational clinical epidemiological study would thus seem to be an appropriate public health response, for the following reasons: - Oral hygiene practices, and particularly brushing techniques, are key components in the maintenance of good periodontal health. On the other hand, poorly applied, it is well established that these factors can generate inflammation and gingival recession, frequently concomitant with damage to calcified dental tissues. - Periodontal conditions lead to cervical and radicular exposure (with clinical loss of attachment), illustrating the aggressiveness of the oral environment and the damage due to brushing, to the cement and the dentine which are 7 to 9 times less resistant than enamel. - The consequences of these lesions, at the tooth-periodontal tissue interface, manifest themselves functionally by dentinal-pulpal hypersensitivity and aesthetically when the lesions are on the anterior teeth. These functional and aesthetic problems necessitate either restorative treatment or periodontal plastic surgery. Dentinal hypersensitivity is one of the first symptoms to appear after cervical wear lesions occur. It occurs during the initial phases of an attack leading to cervical lesions. Epidemiological reports agree on an approximate prevalence in adult populations of 10% to 20%. In this connection, dentinal hypersensitivity, apart from having an impact on quality of life, seems to be the fundamental predictive risk factor for early detection of non-carious cervical lesions and preventive interventions for these conditions. If risk factors for non-carious cervical lesions have hitherto been poorly studied, better knowledge of these conditions would allow the establishment of preventive measures that seek to reduce the incidence of this condition and to diminish its impact, given that the condition has functional, aesthetic and painful consequences that impact on the quality of life of adult sufferers. We are proposing to conduct a study, using general dental practitioners, to identify risk factors for non-carious cervical lesions as diagnosed in dental practice. Apart from the risk factors for acquiring non-carious cervical lesions, we hope to answer questions about methods of management for the lesions, how is prevention organised, which preventive strategy for which risk factors? 3. Aims of the study 3.1. Principal Aim To research the risk factors associated with the occurrence of a non-carious cervical lesion in people aged 18-35 years included seen in general dentistry in Europe including Finland, France, Spain, Italy, Latvia, Estonia, United Kingdom. * Factors to be researched: 1. Clinical loss of attachment 2. Oral hygiene 3. Dietary habits 4. Tobacco and alcohol use 5. Medical predispositions 6. Life events during the preceding 12 months
* Turkey is inside the project as an associate partner. It performs the same study as methodological criteria, but the analysis, because of technical constraints identified in a development phase of the protocol, will be delayed. The Czech Republic is also an associate member. The methodology used in CZ is type CATI interview (by phone) including 700 adults. Only the questionnaire ESCARCEL project is used, no clinical collection is performed.
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
3.2. Secondary aims To record the prevalence of non-carious dental cervical lesions in a population of young adults attending a general dentist for consultation in Europe including Finland, France, Spain, Italy, Latvia, Estonia, United Kingdom (West South England; Bristol area); To record the prevalence of dentinal hypersensitivity in a population of young adults attending a general dentist for consultation in Europe including Finland, France, Spain, Italy, Latvia, Lithuania, United Kingdom; To analyse the relationship between subjective impressions of the dentition and clinical indices.
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4. Study plan and methods of 4.1 Type of study The study is a cross-sectional observational epidemiological study that will take place in Finland, France, Spain, Italy, Latvia, Estonia, United Kingdom. Turkey is involved as associate partner. The study participants are to be ambulatory persons aged 18-35 years included who consult a general dentist belonging to the “Sentinel” network. The standardised clinical examination will take place in connection with a routine check-up in the practice of a private or public dental practitioner. This examination will serve to divide participants into two groups: those who present with positive findings on examination and those who present with negative findings at the clinical examination. Persons who provide informed consent to participate will be asked to complete a self-administered questionnaire. Included in the study:
For every person to be included, the general dentist will Explain the study to the participant Provide him with a letter offering information Request his consent Provide the participant with a self-administered questionnaire Help the participant to complete the dentist questionnaire which covers clinical information and antecedent factors for the condition. The dentist will complete a register of patients affected by non-carious dental cervical lesions seen in consultation and will indicate whether each person was included or not in the study. “Sentinel” dentists will be requested not to modify their usual management practices for patients. This study should not change the dentist–patient relationship. The dentists will remain free to decide their treatment options and follow-up procedures and no out-of-the-ordinary treatment or examination is linked to this study. 4.2 Selection of general dentists General dentists of the “Sentinel” network will be invited to participate in the study. They will receive an invitation letter. The selection of those who will participate (n=20 maximum) will be based on an invitation to participate, a balanced territorial distribution and a regional distribution balancing urban, suburban and rural dentists. Calibrated and trained examiners will have completed a 11/2-day training on use the clinical index to conducting the study including inter and intra examiner reproducibility assessments. The number of GDP was respectively 10 in Estonia, Finland and Latvia, 15 in France, 17 in Italy, 20 in Spain. The epidemiological and national GDP of France, Italy, Latvia and Estonia have already participated in European EGOHID (www.egohid.eu) in 2008-2009 and have already gained quality experience in this field. It is important to understand that, although the ultimate vision of the second phase of the EGOHID project was to have teams of trained sentinel dentists working in primary care collecting comprehensive oral health information on representative quota samples of patients of specific age and socioeconomic groups passing through their practices. In each member state, a local coordinator was appointed and set a target of recruiting 10 to 20 dentists to be trained in the methodology. Only UK opted to use national epidemiologists (2).
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
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4.3 Selection of participants Inclusion criteria for participants o Patients of either sex, ambulatory, who consult a general dentist o Aged 18–35 years, inclusive o Having a good understanding of the national language o Understands and is willing, able and likely to comply with all study procedures and restrictions o Who accept the form of the study and who sign a declaration of informed consent o Who are of good health (in the opinion of the GDP) without clinical abnormality nor abnormal medical history Exclusion criteria o Persons incapable of responding to the questions o Persons having pathology – haemophilia, using anti-coagulants (including plaque anti-aggregants); o Persons using fixed maxillary or mandibular orthodontic appliances; o Persons who had used antalgic (pain relieving) drugs or had used a topical analgesic in the preceding 24 hours; o Persons who required antibiotic cover (following infectious endocarditis, using prosthetic cardiac valves); o An employee of the study site or their immediate family member. 4.4 Number of participants necessary The required number of participants is based on the principal objective, the evaluation of risk factors associated with the occurrence of non-carious cervical lesions. With two controls for each case of noncarious cervical lesion, an expected odds ratio of 2, a risk of 5% and a power of 80%, the required number of participants in Finland, Estonia, Spain (Region of Andalusia), UK (Bristol and Metropolitan West of South England) would be 332. The estimated error margin of 5% (incomplete questionnaires) brings the required number of participants to 350. In France, Italy, the required numbers of participants were 700. 4.5 Sampling method The sampling method chosen to achieve the aims of the study is the method of quotas on site. It comprises four-stage stratification with age, sex, profession and region** (based on the last national census in each country). The number of participants included for each “Sentinel general dentist “ depends (1) of the relative weight of the regional population to which the centre belongs and (2) to the activity profile (number of consultations) of each “Sentinel” general dentist. 4.6. Calibration of Examiners The chief objective of calibration process was to develop a comprehensive instrument to allow for the collection of NCCL oral health epidemiological data throughout the countries of the European Union together with additional documentation to support training, assessment, and comparability. The format of this instrument was to be a full standard clinical assessment form, adaptable and usable at local, national, and European level encompassing a BEWE index, Hypersensibility index, Schiff Index, Loss of attachment, Pocket deeph index, Bleeding index recommended by ESCARCEL. Training was organised on behalf of an European coordinator (DB) and national coordinators identfied in each country. In order to make the best possible use of a total of one day’s face-to-face training (two halfday sessions), participating dentists will received detailed information and training booklet to use at their practices in advance of training (See booklet in annex) The recommendations for training the GDP are: 1. One half day of slide presentations and discussions of the LA, BEWE and Schiff codes and protocol for examination. Information should be done via an e-session. 2. At least one half day of examiner training which will include examination of a set of subjects providing balanced numbers of tooth surfaces with LA Score, BEWE codes 0-3 and Schiff codes. The examination findings of all examiners should be reviewed to identify differences in interpretation. Examinations are to be repeated until agreement is reached among the examiners.
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
This exercise should be conducted by a “senior examiner”. Part of the exercise may involve using extracted teeth; however, the training exercise must include examining live subjects 3. 1/2 days of reliability assessment using live subjects presenting with non carious cervical with severity ranging between 0 and 3 (BEWE). At least 15 patients should be examined per examiner and the “senior examiner” A senior examiner is a dentist with experience in using the BEWE, has high degree (Kappa = 0.75+) of intra-examiner reliability, and has been calibrated and is reliable with another experienced BEWE examiner. In some studies, a senior examiner may work concurrently with the other examiners to reach a final decision. The term “senior examiner” (DB, AN) is used to refer to the standard which will be used to compare with the findings of the examiners in a study.
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3 types of calibration 1 ½ days seminars were organized: Type 1: Training dentists sentinel by the European coordinator of the project (DB) in France, Italy, Spain, Latvia (Kappa> 75) Type 2: Training Coordinator Finnish national epidemiologist by the European coordinator (Kappa> 75), followed by formation of Finnish and Estonian GDP (Kappa> 75) Type 3: Formation of two national epidemiologists by the European coordinator of the project (Kappa> 75) in UK. Country
Training
No. of Dentists
Estonia*
C
AN
10
France*
C
DB
15
Italy*
C
DB – LO
17
Latvia*
C
DB/ES
10
Finland
E
AN
10
UK
D
DB
2
Spain
C
DB
20
Turkey
E
DB
10
Total
94
Training format: (C) Conventional workshop using PowerPoint and discussion over clinical cases; (E) Formation of national officers using training and standardisation toolkits; (D) Formation of national epidemiologists Training days: (DB) Denis Bourgeois; (LO) Livia Ottolenghi (AN) Annamari Nihtila; (ES) Egita Senekola. *: Egohid Team (WWW.egohid.eu) The agenda of the calibration session include 8 sections : Section 1 Introduction Section 2: Basic Erosive Wear Examination Test calibration Evaluation Section 3: Hypersentivity, Schiff Index Section 4 Periodontal Health Assessment Test calibration
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
Evaluation Section 5 Euro Oral Health Erosion Clinical Form Section 6 Questionnaire Section 7: Practical organisations Section 8: Conclusions The trained dentists then returned to their own practices and recruited patients for inclusion in the study from their patients who had pre-existing appointments for dental examinations. National coordinator was in charge to control the sampling plan and the evolution of the type and nature of patients included according to the evolution of the quota. A hot line was initiated to assist GDP if necessary.
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5. Information to be collected The general dentists will recruit sequentially patients who agree to participate corresponding to the eligibility criteria. The study is a cross-sectional observational epidemiological study taking place in (1) metropolitan West of South England; (2) region of Bristol, England; (3) France, Italy, Latvia, Estonia at national level; (4) region of Andalusia of Spain; (5) region of Helsinki in Finland. Inclusion in the study: For every included participant, the general dentist should: o Explain the study to the participant; o Give the letter of information to the participant; o Obtain his informed consent; o Provide the participant with the self-completed questionnaire; o Complete with the participant the “dentist” questionnaire which covers the participant’s clinical and socio-demographic data. The standardised clinical examination and interview will take place in connection with a routine check-up in the practice of a private or public dental practitioner. The “Sentinel” general dentists will be requested not to modify their treatment practices for these patients. This study must not modify the dentist–patient relationship; the dentists remain free to choose the treatment of their choice and their follow-up. No out-ofthe-ordinary treatment or examination will be linked to this study 6. Origins and type of categorical data to be collected The general dentists will recruit sequentially patients who agree to participate in accordance with to the eligibility criteria and their willingness to participate and to complete the self-administered questionnaire. 6.1 Documents to be completed When the participant is initially admitted to the study, the general dentist should complete a register comprising: the participant’s initials; the age, sex, date of examination, included in the study (yes/no), reason for exclusion. Once admitted to the study, the self administered questionnaire completed by the patient and the clinical questionnaire will be provided; these will not include the participant’s name but rather an identifying number made up of the dentist’s number and a sequence number for the participant. The “patient–general dentist” questionnaire, completed by the dentist, will comprise: Criteria of eligibility: o Verification of the inclusion/exclusion criteria; age; date of consultation; socio-demographic data for the patient; age, sex, professional activity, study level achieved, location. Clinical data about non-carious cervical lesions: o Evaluated using the Basic Erosive Wear Examination –BEWE- Index on an ordinal scale ranging from 0 to 3 (0=no erosive wear, 3=Wear with tissue loss on more than 50% of the surface); o Localisation of the lesion (coronal, root surface or crown-root junction). Clinical data about dentinal hypersensitivity: o Evaluated by the Schiff index (ordinal scale, 0=no sensitivity, 3=continuous painful sensitivity on stimulus) and on the dentinal hypersensitivity index (binary, 0 = yes, 1=no on stimulus).
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
Clinical data about periodontal conditions evaluated by (1) loss of attachment (mm); (2) depth of periodontal pockets, and (3) presence or absence of gingival bleeding. All information to collect data are involved in the booklet attached: Booklets Escarcel
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The participant’s self-administered questionnaire, completed before the consultation, will include: o Data on the participant’s oral hygiene practices; o The participant’s Oral Health Related Quality of Life: this scale is a measurement tool comprising questions; responses are made on a 4 point scale; o Data on the participant’s perception of dentinal sensitivity: intensity, duration, origin. o Data on the evaluation of risk factors associated with non-carious cervical lesions (tobacco, medication, diet). o Data on the evaluation of risk factors associated with non-carious cervical lesions: seeking aid in the dental care system; health associated preventive behaviours (weight, size) 7. Data management The data arising from the “dentist” questionnaire, completed by the dentist, will be recorded on a paper form provided to the dentists at the commencement of the study. These paper forms will be returned to the “Sentinel” network using a pre-paid reply envelope. The information from these forms will be entered on computer using the EPIDATA programme and will form the database. The paper forms will be archived with the other documents of this study. The data arising from the “patient” self-completed questionnaire, on paper, will be returned to the “Sentinel” network by the dentist using a pre-paid reply envelope by the general dentist. The information from these forms will be entered on computer using the EPIDATA programme and added to the data base. The paper forms will be archived with the other documents of this study. Responses to the “patient-D” and “patient self reported” questionnaires in the data base will be identified by the sequence number and no names will be recorded against the data item in the electronic file so created. At the end of the study, a report with statistical tables and conclusions will be prepared for analysis and consideration of the findings by the scientific council and those responsible for the project. A scientific report will be written. The data will remain the property of the promoter of the study; all information published will be anonymous. Apart from the report and the scientific publication, no sharing of the data is anticipated. The final report will be published online on the internet site of the Sentinels network after the work has been published in medical and scientific journals. Internet access to the information will be free to all. 7.1. Statistical analysis The questionnaire data will be double entered to identify data entry errors and checked for logical coherence. Analysis will be conducted using the R programme. All questionnaire items will be analysed. Missing data will be flagged. The qualitative variables will be described and compared using the Chisquare test or Fisher’s Exact test if the former test is inappropriate. Quantitative variables will be described and compared using the Wilcoxon test. The analysis will be undertaken in two stages: a univariate analysis followed by a multivariate analysis. The univariate analysis will estimate crude odds ratios, measuring separately the strength of association between the disease and each of the exposure factors, without taking account of other potential confounding factors. An odds ratio of 1.0 signifies the absence of an association. An odds ration significantly greater than 1.0 implies that the exposure factor is a risk factor for the condition (disease) while an odd ration significantly lower than 1.0 suggests that the exposure factor is a preventive factor for the condition.
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
Multivariate analysis allows all the risk factors to be taken into account by simultaneously adjusting for their effects. The standard analytical method for case control studies is multiple logistic regression analysis. This method allows adjusted odds ratios (and their associated confidence intervals) to be estimated for each exposure factor. Odds ratios for risk factors associated with the different questionnaire items (dentinal sensitivity, erosion, periodontal conditions, quality of life scales and dietary variables will be calculated in accordance with the advice of the scientific committee.
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8. Ethical Considerations The refusal of the patient to participate in a study must never interfere with the physician-patient relationship. The design and performance of the study should be should be transmitted to a specially appointed independent committee for consideration, comment and guidance in accordance with national legislation. The protocol has been approved by the National Ethics Committee in each country. 9. Budget Co-funding for this research study will be provided by GlaxoSmithKline Consumer Healthcare in the context of an agreement for observational research with University Lyon1-EZUS, France. 10. Scientific Council Pr. Denis Bourgeois, University Lyon1, France, European coordinator Pr David Bartlett, King’s College University, London, United Kingdom Pr. A. Lussi, University of Berne, Switzerland Pr. Mariano Sanz, Computense University of Madrid, Spain Pr. Ph. Bouchard, University Paris VII, France Pr. N. West, University of Bristol, United Kingdom 11. National Institutions • Italy: University di Roma Sapienza • France: French Union for Oral Health –UFSBD• United Kingdom: University Bristol • United Kingdom : Kingston’s College, London • Spain: University of Grenada • Turkey: National Dental Association; University of Ankara • Finland : Public Health National Service, Espoo • CZ: TNS Sofress • Estonia: National Dental Association • Latvia: University of Riga
12. Timetable Stage 1: March-April 2010 Meeting of the scientific committee and finalisation of the protocol and questionnaires; Stage 2: October-November 2010 Recruitment of the general dentists; Stage 3: January 2011; Launching of the study; June 2011: Termination of the study 13. References 1. Addy M. Dentine hypersensitivity: new perspectives on an old problem. Int Dent J 2002; 52: 367-375.
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
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2. Miller N, Penaud J, Ambrosini P, Bisson-Boutelliez C, Briançon S. Analysis of etiologic factors and periodontal conditions involved with 309 abfractions. J Clin Periodontol. 2003; 30:828-32. 3. Mayhew RB, Jessee SA, Martin RE. Association of occlusal, periodontal, and dietary factors with the presence of non-carious cervical dental lesions. Am J Dent. 1998; 11:29-32. 4. Berg-Beckhoff G, Kutschmann M, Bardehle D. Methodological considerations concerning the development of oral dental erosion indexes: literature survey, validity and reliability. Clin Oral Investig. 2008; 12 Suppl 1:S51-58. 5. Bartlett DW, Shah P. A critical review of non-carious cervical (wear) lesions and the role of abfraction, erosion, and abrasion. J Dent Res. 2006; 85:306-312. 6. Bartlett DW, Palmer I, Shah P. An audit of study casts used to monitor tooth wear in general practice. Br Dent J. 2005; 13;199:143-145 7. Bartlett DW, Ganss C, Lussi A. Basic Erosive Wear Examination (BEWE): a new scoring system for scientific and clinical needs. Clin Oral Invest 2008; 12 (suppl 1): S65-S68. 8. Bartlett DW, Evans DF, Smith BG. The relationship between gastro-oesophageal reflux and dental-erosion. J Oral Rehabil 1996; 23: 289-297. 9. Bardsley PF. The evolution of tooth wears indices. Clin Oral Invest 2008; 12(suppl 1): S15S19. 10. Bardsley PF, Taylor S, Milosevic A. Epidemiological studies of tooth wear and dental erosion in 14-year old children in North West England I. The relationship with water fluoridation and social deprivation. Br Dent J 2004; 197: 413-416. 11. Pegoraro LF, Scolaro JM, Conti PC, Telles D, Pegoraro TA. Non-carious cervical lesions in adults: prevalence and occlusal aspects. J Am Dent Assoc. 2005;1361694-700 12. Lussi A, Schaffner M. Progression and risk factors for denral erosion and wedge-shaped defects over à 6-year period. Caries Res. 2000; 321-330 13. Lussi A, Hellwig E. Erosive potential of oral care products. Caries Res 2001; 35:52-56. 14. Zero T, Lussi A. Erosion – chemical and biological factors of importance to the dental practitioner. Int Dent J 2005; 55: 285-290.
The non-carious dental cervical lesion and associated risk factors An observational, cross-sectional and multi-centre epidemiological study: 2010-2011
