Debonding of orthodontic brackets : effect on marginal microleakage and microcrack of Class V composite resin restorations

Abstract

This study evaluated effects of orthodontic bracket debonding on microleakage and microcrack of Class V composite resin restorations.Fifty-two teeth were divided into four groups. Class V cavity was restored without bonding brackets in group 1. In group 2, 3, and 4, Class V cavity was restored after bonding brackets (group 2: 1.5mm away, group 3: 2.5 mm away, group 4: below CEJ). Thermocycling was carried out and brackets were debonded. Samples were stored in 2% methylene blue solution for 4 hours. Microcrack pattern was observed between brackets and Class V restorations on each tooth. Samples were sectioned and the extent of dye penetration was observed. After evaluating microleakage scores, following conclusions were obtained.1.Microleakage was higher in group of bracket debonding than in group 1 with statistical significance. And, no statistical significance in distance between bracket and Class V restoration (p<0.05).2.Microcrack increased in group 2 with statistical significance when compared with group 1. Group 3 and 4 showed similar pattern of microleakage and did not show statistically significant difference when compared with group 1 (p<.001).In conclusion, debonding of orthodontic brackets increased microleakage of Class V restorations located below the brackets, and microleakage have no relation with distance. Microcrack was also increased when the distance between bracket and Class V restorations was 1.5mm.