Fluoridated elastomers: effect on disclosed plaque.

OBJECTIVE To investigate the effect of fluoridated elastomers on the quantity of disclosed dental plaque surrounding an orthodontic bracket in vivo. DESIGN A randomized, prospective, longitudinal clinical trial, employing a split mouth, crossover design. SETTING The Orthodontic Departments of Liverpool and Sheffield Dental Hospitals. SUBJECTS AND METHODS The subjects were 30 individuals about to start fixed orthodontic treatment. The study consisted of two experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly assigned at the first visit to be placed around brackets on 12, 11, 33 or 22, 21, 43. Non-fluoridated elastomers were placed on the contra-lateral teeth. After 6 weeks (visit 2) the elastomers were removed, the teeth disclosed and a photograph taken. Non-fluoridated elastomers were placed on all brackets for one visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the contra-lateral teeth to visit 1. At visit 4, the procedures at visit 2 were repeated. The photographs were scanned, then the area and proportion of the buccal surface covered with disclosed plaque was measured using computerized image analysis. A mixed-effects ANOVA was carried out with the dependent variable being the area or percentage area of disclosed plaque. RESULTS There was no evidence of a systematic error and substantial agreement for the repeat readings of the same images. The only significant independent variable for the area of disclosed plaque was the subject (p < 0.001). The significant independent variables for the proportion of disclosed plaque were the subject (p < 0.001) and the tooth type (p = 0.002). The independent variable describing the use of fluoridated or non-fluoridated elastomers was not significant for either the area or the proportion of disclosed plaque. CONCLUSION Fluoridated elastomers do not affect the quantity of disclosed plaque around an orthodontic bracket.