NECESSITY OF BEVELS FOR BOX ONLY CLASS-II COMPOSITE RESTORATIONS

Statement of problem. The tooth preparation of a bevel is recommended to improve marginal quality of a composite restoration. However, in sm all Class II restorations, it is unclear if a bevel also contributed t o a better marginal tit.Purpose, This study investigated the influence of tooth preparation design on microleakage of minimal posterior Clas s II composite restorations. Material and methods. Bos-shaped Class II tooth preparations for posterior composite restorations in maxillary premolars were restored with a total etch technique. The tooth prepara tions were beveled or nonbeveled and the box prepared at a right angle cervically or additionally excavated. The facial and lingual box marg ins were also either beveled or unbeveled. The teeth were thermocycled and immersed in a dye solution. After sectioning specimens, dye penet ration at the facial and palatal margins was recorded. Results. A beve l-reduced microleakage both at the cervical and ascending wails. Ename l cracks were observed along certain unbeveled margins as recorded in this study. The additional excavation did not contribute to reduction of microleakage. Conclusions. Tooth preparation of a bevel is recommen ded for an optimal marginal seal in small box-type Class II composite restorations.