The Effect of Rebonding on Microleakage of Composite Resin Restorations

Different methods are proposed for reduction of microleakage of resin composite, for example, the use of incremental method,the use of flowable liner and rebonding. Objectives: The purpose of this study is to evaluate and compare the microleakage of composite restorations by use of rebonding on restoration margins and flowable composite as a liner. Methods: 60 extracted caries-free human premolars were selected,the class V cavities on buccal surfaces were prepared, such that occlusal margins were placed in enamel and gingival margins were placed in dentin. The teeth were randomly divided in to five groups of 12 each. Group 1 was the control,that was restored without any liner or rebonding. In groups 2, 3 and 4, after finishing and polishing, rebonding was in turn performed by Prompt L-pop, Permaseal and SE bond on the restoration margins. In group 5, the cavities were restored by flowable and hybrid composite without rebonding. The specimens were thermocycled, and then sealed using fingernail polish except the occlusal and gingival margins, and then immerged in basic fushine 2% for 24 hours. The specimens were longitudinally sectioned with diamond disks and analyzed by stereomicroscope. The data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Results: There was no leakage by Permaseal at the occlusal margins, and there was a statistically significant difference between Permaseal and control, Prompt-L pop and flowable composite groups and between SE bond with flowable composite. The least microleakage was found in SE bond group, that was statistically different from the flowable composite and Prompt L–pop, but there was no significant difference from other groups. Conclusions: The results of this study indicate that the use of flowable composite as an liner can not reduce the microleakage of composite restorations and none of the restorative systems could eliminate microleakage at the gingival margins.