Abstract
OBJECTIVE: Flowable composite resins are widely used in dentistry, and their biocompatibility is a critical factor. This study aimed to evaluate the cytotoxicity of flowable composite resins with different compositions using an MTT assay on L929 mouse fibroblast cultures. MATERIALS AND METHODS: In this study, four types of flowable composite resins with different compositions were used: nanoparticle-containing (Filtek Supreme - FS), self-adhesive (Vertise Flow - VF), highly filled (G-aenial Universal Injectable - GUI), and fibre-reinforced (EverX Flow - EF) resins. A total of 28 disc samples (seven from each material), each with a diameter of 5 mm and a thickness of 2 mm, were prepared and polymerized. Five different dilutions (1:1, 1:2, 1:4, 1:8, and 1:16) of the test materials were added to the L929 mouse fibroblast culture medium. The effects of the test materials on cell viability were evaluated using the MTT assay at three different time points (24, 48, and 72 h). The optical densities of the cells were measured with a spectrophotometer. The calculated viability percentages (%) were statistically analysed along with their standard deviations. The effects of the materials' dose and incubation time on cell viability were evaluated using two-way ANOVA. A Bonferroni post hoc test was applied to determine which factor or interaction group the difference originated from (p < 0.05 was considered statistically significant). RESULTS: FS, GUI, and EF materials showed no cytotoxic effects at any of the tested concentrations and incubation times; cell viability was found to be above 70% under all conditions. In contrast, undiluted VF material showed cytotoxic effects at all time points, while the 1/2 concentration exhibited cytotoxicity at 72 h. CONCLUSION: FS, GUI, and EF materials are considired to be biocompatible based on ISO 10993-5 criteria, However, the dose- and time-dependent cytotoxicity observed for the VF material limits its biocompatibility. This may be attributed to differences in monomer and filler composition, highlighting the importance of evaluating the biocompatibility of flowable composite resins before clinical use.