Effect ol light-curing time on the cytotoxicity of resin-based cements

Objectives:The aim of this in vitro study was to evaluate the cytotoxicity of resin-modified glass-ionomer lining cements submitted to different light-curing times and applied to an immortalized odontoblast-cell line (MDPC-23). Methods: Forty round-shaped specimens of each experimental material (Fuji Lining LC and Vitrebond) were prepared. They were light-cured for the manufacturersx recommended time (MRT), under-cured (0.5 MRT), over-cured (1.5MRT) or allowed to dark-cure (0MRT). Sterilized filter papers soaked with either 5µL of PBS or 5µL of pure HEMA were used as negative and positive control, respectively. The specimens were placed into wells of 24-well dishes, odontoblast-like cells MDPC-23 (30,000 cells/ cm2) were plated in each well and incubated for 72 hours in a humidified incubator at 37ºC with 5% CO2 and 95% air. The cytotoxicity was evaluated by the cell metabolism (MTT assay) and the cell morphology (SEM). Results:Fuji Lining LC was less cytotoxic than Vitrebond (p <0,05). However, the cytotoxicity of Fuji Lining LC was remarkably increased in the absence of light-curing while the same was not observed for Vitrebond. Conclusions:The length of light-curing (0.5MRT, MRT and 1.5MRT) did not influence the toxicity of both lining materials when they were applied on an odontoblast-cell line-MDPC-23.