Cytotoxicity of a new composite resin material

Composite resin materials are applied onto dentin and thus the risk for the dental pulp has to be assessed. Objective: To evaluate the cytotoxicity of a new dental composite resin (Tetric EvoCeram) in comparison with a known material (Tetric Ceram) in an elution cytotoxicity test and in a dentin barrier test. Methods: Tetric Ceram and Tetric EvoCeram (Ivoclar Vivadent) specimens were covered with a polyester film, light cured, and extracted in basal medium Eagle supplemented with 5% NBS (91.6 mm² sample surface/ml) for 24 h at 37°C. L-929 cells were then exposed to these extracts for 24h (5% CO₂, 37 °C), and cell survival rates were determined (crystal violet assay). In the dentin barrier test device, three dimensional cultures of SV40 transfected bovine pulp derived cells were separated from the test materials by dentin slices (500 µm thickness). The following materials were applied into the cavity part of the device: Tetric Ceram/Excite, Tetric EvoCeram/Excite, Excite, and Tetric EvoCeram. A silicon impression material (President, Coltene) served as a negative control material (100 % cell vitality). After a 24 h exposure period, cell survival rates were measured (MTT test), and statistically analyzed (Mann-Whitney test, a= 0.05). Results: Survival rates of L-929 cell (74% and 69% for Tetric Ceram and Tetric EvoCeram) were not statistically different. In the dentin barrier test, Tetric EvoCeram/Excite reduced cell viability to 93% compared to negative controls. The difference between Tetric EvoCeram/Excite (93%) and Tetric Ceram/Excite (81%) was not significant. Cell reactions caused by Excite and Tetric EvoCeram alone were not different from the negative control. Conclusions: Excite, Tetric EvoCeram, and the combination of both were less toxic than the combination Tetric Ceram/Excite. For the given experimental conditions, the new composite resin can be regarded as innocuous for the dental pulp.