Transdentinal cytotoxicity of experimental adhesive systems of different hydrophilicity applied to ethanol-saturated dentin

摘要

The aim of this study was to evaluate the transdentinal cytotoxicity of experimental adhesive systems (EASs) with different hydrophilicity and dentin saturation solutions (ethanol and water) on odontoblast-like cells. One hundred 0.4-mm-thick dentin discs were mounted in in vitro pulp chambers and assigned to 10 groups. Odontoblast-like cells MDPC-23 were seeded onto the pulpal side of the discs, incubated for 48h. The EASs with increasing hydrophilicity (R2, R3, R4 and R5) were applied to the occlusal side of the discs after acid etching and saturation of demineralized dentin with water or ethanol. R0 (water and ethanol- no adhesive) served as controls. After 24h, cell metabolism was evaluated by SDH enzyme production (MTT assay; n=8 discs) and cell morphology was examined by SEM (n=2 discs). The type of cell death was identified by flow cytometry and the degree of monomer conversion (%DC) was determined by infrared spectroscopy (FTIR) after two photoactivation times (10 s or 20 s). Data were analyzed statistically by the Kruskal-Wallis and Mann-Whitney tests (α=0.05). Dentin saturation with ethanol resulted in higher necrotic cell death ratios for R3, R4 and R5 compared with water saturation, although R3 and R4 induced higher SDH production. Photoactivation for 20 s significantly improved the %DC of all EASs compared with 10 s. A significant positive correlation was observed between the degree of hydrophilicity and %DC, for both photoactivation times. In conclusion, except for R2, dentin saturation with ethanol increased the cytotoxicity of EASs, as expressed by the induction of necrotic cell death.