Σωτηρία Γκιζάνη, Αναπληρώτρια Καθηγήτρια, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Ιωσήφ Σηφακάκης, Επίκουρος Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Βασίλειος Παπαιωάννου, Αναπληρωτής Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Introduction: White Spot Lesion (WSL) is a mark of demineralisation of enamel, which appears as a white spot on tooth surfaces. Unfortunately, it is considered quite a common side - effect of orthodontic treatment with fixed appliances which can sometimes be detectable even 12 years after debonding. The prevalence of WSLs in orthodontic patients varies from 2% to 97% depending on the population, duration of treatment and methods for caries detection. Remineralisation of WSLs may occur naturally by saliva, mainly in the first 2 months after debonding, although this procedure takes time and usually requires patient’s collaboration and improvement of oral hygiene. For non - responders, application of remineralising agents seems to be beneficial. However, the recent review by Sonesson and coworkers [Sonesson et al., 2016] concluded that there is lack of reliable evidence to support the application of remineralising strategies as method for the management of post - orthodontic WSLs. The effectiveness of ClinproTM White Varnish (3M ESPE) [functionalized tricalcium phosphate (fTCP) with 5% sodium fluoride] in comparison with other fluoride and CPP - ACP varnishes has been evaluated in several studies but they were in vitro studies which cannot completely stimulate conditions within the oral cavity. To our knowledge, no similar clinical study has been carried out so far.
Aim: To evaluate the effect of ClinproTM White Varnish application on the remineralisation of WSLs in patients from the Postgraduate Orthodontic clinic of the National and Kapodistrian University of Athens (NKUA) and Orthodontic Department of 251 General Hospital of Greek Air Force for 16 weeks after debonding as assessed by the patients and the dentist. The primary outcome was the severity of WSLs from photographs [ICDAS II modified by Almosa, Almosa et al., 2014] while the visible improvement, according to the visual analog scale (VAS - scale) by Huang and cowokers [Huang et al., 2013] as assessed by the patients, is the secondary outcome.
Materials and Methods: Sixty - four patients of the Postgraduate clinic of Orthodontics and Orthodontic Department of 251 General Hospital of Greek Air Force were invited to participate based on the following eligibility criteria: at least two white spot lesions on the buccal surface of their upper anterior teeth (incisors, canines or first premolars) at the time of debonding and duration of orthodontic treatment with fixed appliances at least 1 year. Patients who had severe chronic diseases and continuous use of medication causing xerostomia were excluded. Participants were randomly assigned into 2 groups based on a computer generated randomization list: a) Varnish group (Varnish - experimental group): patients received application of ClinproTM White Varnish with fTCP (22,600 ppm F) at baseline and 8 weeks and b) Placebo group (control - placebo group): patients received a mock product (mixture of non - fluoridated toothpaste with water) which had similar color and texture with varnish, at the same timepoints. The study employed a two - arm double blind randomized design over 16 weeks. At the time of debonding, 8 and 16 weeks follow up, clinical examination and varnish application carried out by two trained and calibrated examiners. Three clinical digital photos were taken of each patient, one frontal and two lateral photos, based on standardized parameters and using cross - polarized filters. The original ICDAS categories were merged from seven scores to four scores according to Almosa and coworkers [Almosa et al., 2014]: Score 0a = no visible signs of demineralisation (ICDAS 0); Score 1a = enamel caries when viewed dry or wet (ICDAS 1 and 2); Score 2a = localized enamel breakdown or underlying dark shadow (ICDAS 3 and 4); Score 3a = dentin caries with visible cavity (ICDAS 5). The photos were taken at baseline, 8 and 16 weeks and they were examined as well as evaluated by two examiners, independent from the examiners who did the clinical examination. The selected sites were evaluated using the VAS - scale from 0mm to 100mm (0 mm- no change- up to 100 mm-WSL completely disappeared) by the patient and the dental professional separately. All patients were examined at debonding, 8 and 16 weeks follow up, by two trained and calibrated experienced dentists (κ>0.80%). Information about the following variables were selected: gender, age, orthodontic treatment duration, tooth type and oral hygiene which was assessed as an overall score on patient level.
Statistical analysis: Descriptive statistics and cross tabulations were performed to describe baseline characteristics of the sample. Crude and multivariable mixed effects ordinal logistic regression models were built to identify the effect of intervention (ClinproTM White Varnish) on the severity of WSLs at 8 and 16 weeks after bracket removal, adjusted for baseline estimates. Likewise, univariable and multivariable mixed effects ordinal logistic regression models were also built for the effect of intervention on patient reported and dentist reported VAS scores. Scatter plots were constructed on patient level and Spearman’s rho correlation coefficient was calculated for the association between patient and dentist related average VAS scores (in original scale). The level of statistical significance was pre-specified at p< 0.05. Statistical analyses were performed with STATA version 15.1 software (Stata Corporation, College Station, Tex, USA).
Results: Finally, 59 patients (25 boys and 34 girls), aged between 12 and 18 years-old, complied with the protocol and participated in the study (mean age: 15.1, SD: 1.5, range: 12- 18, Varnish group: n=32 and Placebo group: n=27). A total of 390 teeth were examined at baseline for both groups, relatively equally distributed across tooth type. At 8 weeks, only type of tooth was a significant predictor of achieving higher WSL scores, compared to lower categories. Specifically, lateral incisor versus central had 2.6 times higher odds (95%CIs: 1.14, 5.88; p=0.02) of achieving a higher WSL score as represented by the combined (WSL 1, 2) category, compared to score 0. At 16 weeks, patients that received the ClinproTM White Varnish, presented 78% lower odds of having worse WSL scores (combined 1, 2 category) compared to score 0 (Varnish group vs Placebo group: OR= 0.22; 95% CIs: 0.08, 0.59; p=0.003) after adjusting for a number of predictors. In addition, there were 3% lower odds (OR= 0.97; 95% CIs: 0.95, 0.99; p=0.008) of combined 1, 2 WSL scores compared to 0 score for each unit increase in the hygiene index. As far as VAS score is concerned, both patient reported as well as dentist reported average VAS scores at 8 and 16 weeks were higher for the Varnish group. A significant correlation was observed between patient reported and dentist reported scores at both timepoints (8 weeks, Spearman’s rho: 0.70, p<0.001; 16 weeks, Spearman’s rho: 0.58, p<0.001). In the multivariable model at 8 weeks, lateral incisor versus central presented 72% lower odds of achieving VAS score of 50-100 compared to the low VAS score of 0-49 (OR= 0.28; 95%CIs: 0.11, 0.68; p= 0.005). In addition, first premolar versus central incisor presented 62% lower odds for high VAS score (ie, VAS 50-100 compared to VAS 0-49: OR= 0.38; 95%CIs: 0.15, 0.95; p= 0.04). Varnish application presented a significantly positive effect on dentist reported VAS scores at both 8 and 16 weeks according to the multivariable model and after adjusting for a number of parameters such as age, sex, treatment duration, hygiene index, WSL score and tooth type. Specifically, at 8 weeks, there were 8.47 times higher odds of dentist reported VAS 50 - 100 compared to the lower VAS category (ie VAS 0 - 49) in patients who received ClinproTM White Varnish compared to Placebo group (OR= 8.47; 95%CIs: 1.36, 52.83; p=0.02).
Conclusions: Patients receiving ClinproTM White Varnish (tricalcium phosphate) showed a significantly larger improvement of their WSLs at 16 weeks after debonding compared to the Placebo group, despite the fact that the lesions of this group was more severe initially. Regarding visual improvement, patients who received ClinproTM White Varnish gave higher VAS - scores than patients from the Placebo group at 8 weeks. Both patients and dentists gave comparable VAS - scores at both timepoints.