In vitro cytotoxicity of 5 dentine adhesive systems

Abstract

Dentin adhesives are placed directly on dentin wound from which the smear layer has been removed. Considering that dentin permeability is responsible for pulpal reactions, in this study we investigated the cytotoxic effect of primer and bond components of several dentin adhesive system (DAS) agents in an originally designed experimental model that included the analysis of post-diffusive and direct effects immediately, 24 hour, and 76 hours after the contact with a highly sensitive in vitro living test system containing L 929 fibroblasts. 20 intact premolars were used and the primers or bonds were placed in cavities, allowing a 24 hour contact with the roof of the pulpal chamber, and 1 mm thick dentin separating it from the culture medium (CM) in micro-wells. CM from this experimental group, experimental groups containing directly added DAS components, as a positive control, teeth only or just CM as a negative control, were then transferred into micro-well plates with L929 cells. The obtained results indicate that the post-diffusive effects of DAS components lead to an increasing, time-dependent, inhibition of L929 cell proliferation and that this effect is more pronounced in the direct presence of different concentrations of DAS. The in vitro observed toxic effects of DAS components should be less pronounced in vivo considering the fact that in healthy pulp the exchange of extra-cellular fluid is fast which reduces the possibility of toxicity. Therefore, it is necessary to perform in vitro investigations to obtain an understanding of the optimal characteristics of dental materials which can improve the ability to develop more biocompatible material.