Cytotoxicity of Dental restorative Composites on Gingival Epithelial Cells

The development of resin-based dental materials bonded to tooth surfaces contributes to major developments in dental restorative techniques. However, adverse biological reactions have been attributed to the monomers released from dental resin materials. Objective: This study was to investigate the cytotoxic effects on gingival epithelial cells by the composites and to determine when the monomers become non-toxic. Methods: Composite discs (5 by 2 mm) from SDR, GCK, Filtex, and Esthet-X were prepared, cured and then were incubated with DMEM for periods ranging from 30 minutes to 10 days. Culture media was collected, filter sterilized after each incubation. Epithelial cells (1x10⁵)were incubated with composite-conditioned media for 24 hours. Cytotoxicity was evaluated by MTT assay, and composite effect on superoxide dismutase activity was determined. Assays were done using triplicate samples. The data were analyzed by one-way analysis of variance, with a level of significance of p <0.05. Results: Composite culture supernatants were found to be cytotoxic initially. After 24 hours, only 25 ± 9% viability of cells was observed when treated with SDR and Esthet-X. Viability of these cells was increased to 90±7% after 96 hours , while less than 50% viability was seen with cells treated with GCK and Filtek. The composites were found to inhibit the superoxide dismutase activity, but after 96 hours, cells treated with SDR and Esthet-X inhibited only 11-14% of activity, when compared to the control. Conclusion: The study demonstrated that the composite supernatants are toxic to the cells initially, but the toxicity of SDR and Esthet-X were found to be minimal after 72 hours. Clarifying the toxic effects of monomers in a composite is important for evaluating the safety use of these dental materials.

Supported by UT College of Dentistry Alumni Foundation.