The individuals included in the study were all undergoing psychiatric and/or medical outpatient treatment at clinics for eating disorders during 2005 – 2013. Because of the assumed relation between eating disorders and dental problems, all patients at these clinics were offered a referral for a dental examination. The patients who were interested were then offered a dental examination at a university dental clinic (University of Oslo, Norway). The eating disorder diagnoses were made by the professional team at the eating disorder clinics. Of 72 referred patients examined at the university dental clinic, 62 had been diagnosed with BN, eight with AN, one with binge-eating disorder (BED) and one with an unspecific eating disorder. Self-induced vomiting was, or had been, a part of the eating disorder for 67 patients, and only these individuals were further studied. After the examination, one additional individual was excluded from the study because of crowns and onlays on all lower molars and upper front teeth.
Prior to the dental examination, each patient was interviewed by one examiner. The standardized interview was based on questions from a previously tested questionnaire,[26,27] and discussed the patient's present medical condition, other diseases/diagnoses and medical history. In addition, the examiner asked each patient about their dietary habits, such as consumption of acidic beverages and foods. This consumption was assessed by frequency questions with five possible responses: several times daily, once daily, 3–5 times weekly, 1–2 times weekly and less than once weekly. The participants were also asked if they vomited after eating, and if so, how often (daily, several times weekly, monthly and occasionally) and how long time since the last episode of vomiting.
The duration of self-induced vomiting was recorded during the interview, with three possible responses: 3–7 years, 8–10 years and more than 10 years duration of self-induced vomiting. Only a few participants specified the time of last episode of vomiting, and because this ranged from weeks to years, it was therefore not further considered in the study. The frequency of SIV was registered as times of vomiting per week, and ranged from two to 210 times per week.
Calibration and Clinical Examination
The intra-oral clinical examination was performed by one previously calibrated clinician (AM). The examiner was calibrated with four other clinicians (intra- and inter-examiner agreement values of mean κw = 0.95 and mean κw = 0.73; range 0.71 – 0.76, respectively). For more details see Mulic et al..
The clinical examination was performed in a dental clinic with standard lighting, using mirrors and probes. Access saliva was removed from the teeth with compressed air and cotton rolls. The lingual/palatal and buccal surfaces of all teeth, and the occlusal surface of premolars and molars, were examined. For severity grading of dental erosion, a well established scoring system with the ability to diagnose early stages, as well as more advanced stages of erosion, was required. Scoring of dental erosion was therefore performed according to the Visual Erosion Dental Examination (VEDE) system:[27–29] Score 0: No erosion; score 1: Initial loss of enamel, no dentine exposed; score 2: Pronounced loss of enamel, no dentine exposed; score 3: Exposure of dentine, < 1/3 of the surface involved; score 4: 1/3–2/3 of the dentine exposed; score 5: > 2/3 of dentine exposed. The number and distribution of affected teeth and surfaces were also registered. When surfaces were either filled, repaired with a crown or a veneer, affected by attrition or abrasion, or the tooth had been extracted, the surfaces and teeth were recorded as missing and excluded.
The study was approved by the local Regional Committee for Medical Research Ethics and The Norwegian Social Science Data Services. Written, informed consent was obtained from all participants.
The statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS, Chicago, IL, USA, version 20). Presence of dental erosive wear was used as the dependent variable. Frequency distributions, descriptive and bivariate analyses (Chi-square test) were conducted to provide summary statistics and preliminary assessment of the associations between independent variables and the outcome.
The level of significance was set at 5%.
BMC Oral Health. 2014;14(92) © 2014 BioMed Central, Ltd.