Microleakage of three contemporary bulk fill resin composites; Thermoviscous preheated, sonic fill and flowable bulk fill in class I cavities: In vitro study

Objective: The aim was to compare the microleakage of three different types of bulk fill composites in class I cavities.
Materials and methods: Fifteen freshly extracted molars were selected for this study. Standardized occlusal cavities measuring 5X4X4 mm were prepared. The cavities were distributed among the three tested groups according to the type of resin composite; whereas; Group A: Viscalor thermoviscous preheated bulk fill, group B: Sonic fill bulk fill composite and group C: SUREFIL SDR™ flowable bulk fill. The restored molars were subjected to artificial aging, then teeth were immersed in 2% methylene blue dye solution for 24 hours at 37°C. Each tooth was then sectioned into 2 halves and the specimens were examined under a stereomicroscope. All the specimens’ images were subjected to image analysis to determine the depth of dye penetration in Mm. Statistical analysis was performed with IBM® SPSS® Statistics Version 20 for Windows.
Results: A statistically significant difference was found between group B and each of group A and group C where (p=0.018) and (p < 0.001) respectively. No statistically difference was found between group A and group C where (p=0.332). The highest mean value of dye penetration was found in group B, while the least mean value was found in group C.
Conclusions: None of the tested composites could completely eliminate microleakage along the tooth restoration interface in class I cavities. Flowable bulk fill composites and preheated composites showed less microleakage in comparison to the sonic fill composite.