The aim of the study was to compare the microleakage along the margins of composite restoration in class II cavities using horizontal increment, oblique increment and bulk placement technique. Methods and Material: standardized class II cavities were prepared in 30 extracted human permanent molars. The teeth were restored with nanohybrid composite (Tetric N Ceram) and bonding with adhesive systems (3M ESPE Adper Single Bond 2 adhesive) using three different placement techniques. Microleakage evaluated after thermocycling (500 cycles) of the specimens. Statistical analysis: One way ANOVA test was used for inter comparison of microleakage between the groups at the 0.05 level of significance and multiple comparison by Tukey test were used. Results: Mean microleakage score of group I- 1.20, group II- 1.05 and group III -2.75 Conclusions: None of the insertion techniques used in this study was able to prevent microleakage, though the lowest microleakage values were obtained when the oblique incremental technique was used.
Keywords: Horizontal increment, oblique increment, bulk placement, polymerization shrinkage, microleakage, thermocycling.