Dose- and Time-dependent Cytotoxic Responses of Contemporary Glass Ionomer Cements: An in Vitro Study

Background The biocompatibility of restorative materials is critical due to their close contact with vital tissues. Resin-modified glass ionomer cements have been developed to improve mechanical properties; however, their cytotoxic effects remain controversial. Materials and Methods In our study five glass ionomer cements with different compositions were used: four resin-based (Ionosit Baseliner, Nord Liner, Glass Line, Ionoseal) and one conventional type (Espe Ketac Molar Easymix) were tested. A total of 35 (7 for each material) samples evaluated with standardized discs (5×2 mm). Extracts were prepared according to ISO standards and applied to L929 mouse fibroblast cells at four concentrations (100%, 75%, 50%, 25%) for 24 and 48 hours, and cell viability was assessed using the MTT assay. Absorbance was measured using a spectrophotometer at the appropriate wavelength. Results Nord Liner and Ionoseal glass ionomer cements showed no significant reduction in cell viability compared with controls, whereas Glass Line and Ionosit Baseliner exhibited cytotoxic effects in a time- and dose- dependent manner (p < 0.05). Conclusions The cytotoxic responses of glass ionomer cements varied according to material composition, concentration, and exposure time. Among the tested materials, Nord Liner and Ionoseal demonstrated more favorable cell viability profiles under the tested in vitro conditions. These findings highlight the importance of material composition in restorative procedures performed close to pulp tissues.