بررسي تاثير دماهاي متفاوت كامپازيت رزين و الگوهاي تابشي مختلف بر ريزنشست ترميمهاي كامپازيت رزين

Effect of different composite resin temperatures and different light exposure patterns on microleakage of composite resin restorations

Introduction: The reaction of polymerization can be controlled by the light exposure pattern and the temperature. The purpose of this study was to evaluate the effect of different light exposure patterns and composite temperatures on microleakage of light cured composite resin restorations. Materials and Methods: In this interventional study, class V cavities were prepared on 200 extracted human molars. Then the teeth were randomly divided into four main groups according to different light exposure patterns of High Intensity Program (HIP), Low intensity program(LOP), Puls Program(PUL) and Suggested Progressive Program(SUP) and 5 subgroups according to different temperatures of composite during curing (5°C, 20°`, 35°x, 500 and 65°C). After thermocycling and dye penetration, measurement of microleakage was done using a stereomicroscope. The data were analysed using SPSS software (ANOVA). Results: ANOVA showed that both in enamel and dentinal margins, a significant decrease in microleakage has occurred in SUP group. Microleakage in enamel and dentinal margins was significantly higher in HIP group than the other groups. No significant difference was observed in the rate of microleakage among the 5 subgroups with different temperatures. Conclusion: SUP light curing pattern could be considered for improving composite resin restorations as a superior light exposure pattern due to its ability in Polymerization control, reducing polymerization shrinkage stress and microleakage. Prewarming of the composites is a practical and easy way to improve composite properties for dental restorations.