Effects of Fluoride Varnishes on Enamel Decalcification Around Orthodontic Appliances

Decalcification around orthodontic appliances continues. Objectives: To investigate the effect of a fluoride releasing adhesive and fluoride varnish application on demineralization around orthodontic appliances in vivo, and the effect of varnish application before bracket bonding on bond strength in vitro. Methods: In vivo: Orthodontic brackets were placed on 20 patients using a fluoride releasing adhesive, APC-Plus, and Transbond XT which does not release fluoride. A split arch/mouth design was used, for example, upper-right and lower-left receiving one adhesive while the upper-left and lower-right received the other. Fluoride varnish (Duraflor) applied around orthodontic brackets of one maxillary or mandibular arch but not the other. Plaque scores every 4 months and decalcification scores after 16 months were recorded. In vitro: Fluoride varnish was applied and brackets were bonded to 90 extracted human premolars, 30 minutes or 10 days prior to bonding. Controls without varnish were included. Bond strength was determined utilizing a mechanical testing machine. Adhesive Remnant Index (ARI) was recorded. Data were analyzed with bivariate analysis, ANOVA and Tukey–Kramer statistical tests. Results: Teeth with varnish had significantly less decalcification than teeth without (mean score of 1.24 vs 1.53 with a std error of 0.04, p<.001). No significant differences were found due to location of varnish (p=0.40) nor adhesive utilized (p=0.89). Bond strength was not statistically different when application times were compared (p=0.51). Statistical differences of ARI were not judged to be clinically significant; largest = 1.0. A bivariate analysis of total plaque score versus total decalcification was more significant without varnish (p=0.06) than with (p=0.18). Conclusions: Fluoride varnish reduced decalcification during active orthodontic therapy. Use of a fluoride releasing adhesive did not reduce decalcification. Time of varnish application did not affect bond strength or ARI.