Human and bovine pulp-derived cell reactions to dental resin cements.

OBJECTIVES: The objective of this study was to evaluate the cytotoxic reaction of transfected human pulp derived cells (tHPDC) and transfected bovine pulp derived cells (tBPDC) after exposure to resin cements [RelyX UnicemClicker (RX), MaxCem (MC), Panavia F 2.0 (PF), BisCem (BC), and Bistite II DC (BII)] and to compare it to the generation of reactive oxygen species (ROS). MATERIALS AND METHODS: Set materials were extracted in culture medium, cell survival as a measure of cytotoxicity was determined photometrically using crystal violet after cells were exposed to the extracts for 24 h. The generation of ROS was detected by flow cytometry after cells were exposed to extract dilutions for 1 h. RESULTS: The ranking of the least to the most cytotoxic material was: RX < BII < PF < BC < MC for both cell lines, but for tHPDC, only MC and PF eluates were different from untreated controls. Generally, tBPDC were more susceptible to materials than tHPDC, but only for RX and BC was this difference statistically significant. All undiluted extracts increased ROS production in both cell lines but to a higher amount in tHPDC than in tBPDC. CONCLUSIONS: tHPDC reacted less sensitive than tBPDC in the cytotoxicity test but with the same rank order of materials. In contrast, the cellular oxidative stress reaction was more pronounced in tHPDC than in tBPDC. CLINICAL RELEVANCE: Depending on the residual dentine layer in deep cavities, biologically active resin monomers or additives released from resin cements may influence the dentine­pulp complex, for instance, its regenerative and reparative capacities.

Oxidative stress and cytotoxicity generated by dental composites in human pulp cells.

Dental composites are a source of residual monomers that are released into the oral environment. Since monomers act on cultured cells through reactive oxygen species (ROS), we hypothesized that composites generate ROS associated with cytotoxicity. Human pulp-derived cells were exposed to extracts of methacrylate-based materials including triethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate-free composites (Tetric Ceram, Tetric EvoCeram, els, els flow, Solitaire 2) and a silorane-based composite (Hermes III). The materials were polymerized in the presence and absence of a polyester film and then extracted in culture medium. The generation of ROS was measured by flow cytometry, and cytotoxicity was determined as well. Methacrylate-based composites reduced cell survival but varied in efficiency. Undiluted extracts of Solitaire 2 specimens prepared in the absence of a polyester film reduced cell survival to 26% compared with untreated cultures. Cytotoxicity was reduced when specimens were covered with a polyester film during preparation. Cytotoxicity of the composites was ranked as follows: Solitaire 2 >> els flow > Tetric Ceram = Tetric EvoCeram = els > Hermes III. The generation of ROS followed the same pattern as detected with cytotoxic effects. A positive correlation was found between ROS production and cell survival caused by extracts made from materials not covered with a polyester film. These findings suggest that components released from composites affect cellular signaling networks through ROS formation. Regenerative and reparative capacities of the dentine-pulp complex may be impaired by biologically active resin monomers released from composite restorations.