Comparing the Microleakage of Bulk-Fill (flowable, packable) Composite Restorations and Conventional Light-cured Composites

Introduction and aim: Bulk Fill composites have increased polymerization depth and their contraction stress, and cuspal deflection are reduced in comparison with conventional composites. Therefore, it is claimed that their microleakage is reduced. The aim of this study was to compare microleakage of (flowable and packable) Bulk Fill and conventional resin composites. Materials and Methods: This in vitro experimental study was done on sixty human extracted premolars. Standard class II cavities (4 mm in height, 3 mm in length bucco-lingually & 1.5 mm in axial depth) prepared in the teeth. The teeth were randomly divided into three groups based on the type of composite. Group I: Bulk Fill (Xtra Fill packable; Voco) composite, Group II: Bulk Fill flowable (Xtra base; Voco) and Group III: conventional composite (Grandio; Voco). Total-etch bonding system (5th generation) was applied in all cavities. After restoration, teeth were thermocycled. Finally, the microleakage rate was evaluated using a stereomicroscope. The data were analyzed using SPSS software, and Chi-square test. Results: The results indicated that there was no statistically significant difference between enamel and dentinal margins in Bulk Fill Packable and conventional composites (P=0.06). In Bulk-fill Flowable group, dentinal margins had greater dye penetration to enamel margin in the axial surface (P=0.02). There was no significant difference between the three groups in terms of marginal microleakage of enamel and dentin (P=0.4). Conclusion: Finally, we conclude that the use of Bulk Fill Flowable composites on dentinal cavity is not suitable with the manufacturer's recommended thickness. To prove these results, it is necessary to design and perform long-term laboratory and clinical studies. Furthermore, the use of the incremental technique for placement of composites -even with the Bulk-filled group- sounds to be more logical.