Abstract:

Objective: The aim of this in vitro study was to evaluate the effects of different application modes of the universal adhesive system on the microleakage of Class V flowable composite restorations. Materials and Methods: In this study, sixty sound human premolar teeth were used. Standardized Class V cavities were prepared on the buccal surfaces of teeth, with the cervical margin on the dentin and the occlusal margin on the enamel surface. Specimens were randomly divided into 6 groups according to composite resin type (Filtek Z250/FZ, Metafil Bulk Fill/MB, and Nova Compo HF/NC) and application modes of the universal adhesive (selective etch/SEE and self-etch/SE): Group FZ+SEE, Group FZ+SE, Group MB+SEE, Group MB+SE, Group NC+SEE, and Group NC+SE. The specimens were stored in distilled water for 24 hours at 37°C and subjected to 10,000 thermocycles. Then, the teeth were stored in 0.5% methylene blue dye for 24 hours. They were examined under a stereomicroscope (40x) to evaluate microleakage. The data were statistically analyzed using the Kruskal-Wallis and Mann-Whitney U tests (p<0.05). Results: At the occlusal margin, Group MB+SE showed a statistically lower microleakage value compared to Group FZ+SE, and Group MB+SEE showed a statistically lower microleakage value than Group FZ+SEE (p<0.05). For all restorative materials, at both the occlusal and cervical margins, no significant differences in microleakage were found between the application modes (p>0.05). Except for Group NC+SE, statistically higher microleakage scores were observed at the cervical margin than at the occlusal margin for all restorative materials (p<0.05). Conclusion: It has been determined that Class V flowable bulk-fill composite resin restorations with both application modes of the universal adhesive system have a better microleakage performance than microhybrid composite resins at the occlusal margin.

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