Comparison of microleakage from gingival wall restorations with and without sonically activated bulk-fill composite resins and incrementally layered composite resin: A laboratory experimental study

One of the factors that determine the success of proximal composite restorations is a good marginal adaptation at the interface area. During polymerization, composite resin will undergo contraction which may cause gap formation between the wall cavity and restoration. The gap can cause microleakage and provide a passage for bacteria, fluid, molecules, and ions. The purpose of this study was to analyze the microleakage from gingival wall restorations with and without sonically activated bulk-fill nanohybrid composite resins and incrementally layered nanohybrid composite resins. Standardized Class II cavities were prepared on 30 extracted human upper and lower human teeth and were randomly assigned to three groups: filled with sonically activated bulk-fill composite resin, filled without sonically activate resin, and filled incrementally with resin. The specimens were stored in distilled water for 24 hours, were subjected to thermocycling, and were followed by immersion in 1% methylene blue dye for 24 hours. The teeth were sectioned longitudinally, were evaluated for microleakage under a stereomicroscope at 25x magnification, and were scored from 0-3. The Kolmogorov-Smirnov test was used to perform the statistical analysis. None of the techniques was capable of eliminating microleakage from gingival wall cavity preparations. There were no statistically significant leakage differences among the three groups.