In vitro Evaluation of Microleakage of Orthodontic Brackets Bonded Using Methacrylate and Silorane Base Composite

One of the orthodontic treatment problems, which causes marginal gaps and microleakage between tooth and composite is microleakage of composite bonding of orthodontic brackets. The microleakage formation permitting the passage of bacteria and oral fluids, which may cause white spot lesions under the brackets surface area.This is a clinical problem during orthodontic treatment. Few studies have been conducted in this area. The aim of this study was comparison of microleakage of composite silorane base and methacrylate base composite in orthodontic brackets. Thirty human premolar were collected and divided into 2 groups. In group 1, 15 orthodontic brackets were bonded using silorane base composite, in group 2, 15 orthodontic brackets were bonded using methacrylate base composite. Then the teeth were kept in water and thermo cycled(500×, 5-55°C). Specimens were further sealed with nail varnish, stained with 5% basic fuchsin for 24 hours. Then, all teeth sectioned and dye penetration rate were examined by an esteriomicroscope, and scored 0 to 3 for marginal microleakage for the bracket- adhesive and adhesive-enamel interfaces. The data collected analyzed with SPSS16 software, and fisher exact and Mann Whitney tests. Microleakage values were lower in silorane composite than in the methacrylate group, and this difference was found to be statistically significant(P-value =0.03). Also, the rate of microleakage between adhesive-bracket than adhesive-enamel interface was meaningful(P-value=0.025). The results of the current relealed that silorane-bass silorane-base composite provided low microleakage for orthodontic brackets, for this reason, it could be used it for bonding brackets.