CYTOTOXICITY STUDIES OF DENTAL RESTORATIVE MATERIALS USING HUMAN PERIODONTAL-LIGAMENT CELLS IN-VITRO

A model that simulates conditions of clinical practice in vivo and all ows extended exposure of test cells to test substances, was evaluated in vitro by screening the toxicity of seven dental restorative cements . Millipore filter discs, 0.45 mum pore size, or preserved dentine sli ces were used as diffusion barriers between test cells and test substa nces. Cytotoxicity was assessed by estimating cell loss from monolayer s and by evaluating cytopathic changes in cultured cells. After 24 h e xposure to the test materials results were in general agreement with r eported observations from similar studies. However, extended exposure to composite resins gave rise to severe cytotoxicity, which has not be en reported previously. In addition, monitoring of cultures by inverte d microscopy demonstrated attempts at recovery in damaged monolayers w ith viable cells migrating and proliferating into areas of earlier cel l loss. This supports observations in vivo of transient pulpal injury associated with the corresponding materials.