Effect of Composite Resin Volume and Rapid Curing on Microleakage of Composite Restorations

Aim: Microleakage is one of the causes of failure of composite restorations that influenced many factors. The aim of this in-vitro study is to evaluate the effect of composite volume and rapid curing on microleakage of composite restorations. Materials and Methods: 168 bovine incisors were randomly divided into 12 groups. Cylindrical cavities of 3 different diameters (2, 3 and 4 mm) and 2 different depths (1 and 2 mm) were prepared in the middle of the buccal surfaces of the teeth. The cavities were restored with a 7th generation adhesive system and micro-hybrid composite resin. Six of the groups were cured at 1000 mW/cm2 light power, while the other 6 groups were cured at 3200 mW/cm2. The restored teeth were immersed in 1% methylene blue solution for 24 hours. Then, the teeth were cut vertically to pass through the center of the restorations. The amount of microleakage was examined under a microscope. Data was analyzed with One-way Anova, Tukey and t tests (p=0.05). Results: The highest average microleakage scores at the incisal margin were observed in the 3x2 mm sized cavities cured at 3200 mW/cm2 light power and in the 4x2 mm sized cavities cured at 1000 mW/cm light power (mean score= 0.86, p>0.05). The highest mean microleakage score at the gingival margin was observed in the 3x2 mm sized cavities cured at 1000 mW/cm light power (mean score: 1.43, p>0.05). Conclusion: Considering the Pi value as 3.14, rapid polymerization of composite restorations with 3200 mW/cm2 power, a volume of 3.14 mm3 to 25.12 mm3 does not affect microleakage.