Evaluation of the effect of different light cure devices/modes on the micro-leakage of class V composite restoration: (A comparative in vitro study)

Abstract

Introduction: Polymerization shrinkage has remained the major problem of composite restorations.This shrinkage can lead to micro-leakage between the composite material and tooth structure that adversely affect the longevity of the restoration. Many improvements of materials and curing devices had occurred to overcome these drawbacks. This study aimed to assess and compare the effects of different light cure devices/modes on the leakage of class V compositerestoration. Materials and Methods: A total of 64 standardized cavities (Cl V) were prepared on the buccal and palatal surfaces of 32 recently extracted human premolars. Teeth were divided randomly into 4 groups (N=8) according to the type of light curing unit used. All cavities were restored using flowable composite resin (3M ESPE) shade A2, and then they were finished and polished according to manufacturer's instructions. The specimens were subjected to thermocycling and dye immersion in 2% methylene blue. Then all teeth were sectioned longitudinally and examined for dye leakage scores under stereomicroscope with (40 X) magnification. Results: Using one- way ANOVA analysis and Student's t-test.The results of this study revealed that there were statistically significant differences (p<0.01) between Standard continuous and other modes of LED light. Conclusion: The Standard continuous mode of light curing showed more microleakage than the other modes. The soft start polymerization showed the least microleakage. The gingival margins showed more microleakage than the occlusal margins in all groups.