Objectives: We found recently that dental bonding substances tested alone or in combination with composites are far more cytotoxic than composite materials alone. These data are in line with several cytotoxicity studies but contradict in vivo studies which have underlined the beneficial effects of bonding materials. The aims of the present study were: (1) To develop a preparation method for composite specimens resembling conditions in the oral cavity and (2) to analyse the influence of bonding substances on the cytotoxicity of 6 different composite materials. Methods: Cylindrical composite specimens were prepared in polyethylene blocks containing 4 mm diameter cylindrical holes (cylinder height 2 mm), covered with mylar and light cured from one end for 40 s. In a second series of experiments, composite specimens were combined with bonding materials. Bonding was first applied onto mylar in one or two layers and light cured according to the manufacturers' instructions. Subsequently, the polyethylene moulds were placed on top of the bonding materials and composites prepared as before. Specimens were added to L-929 fibroblast cultures immediately after production or following preincubation for 7 days under cell-culture conditions. After incubation for 72 h, cell numbers were determined by flow cytometry. Results: Results demonstrate that the cytotoxicity of all 6 tested composites was significantly different (p<0.0001) and was diminished after 7 days of preincubation (p<0.0001). Bonding substances had no statistically significant influence on the cytotoxicity of composite materials (p=0.159). Conclusions: This study demonstrates that cell culture toxicity data are highly model dependent and that internationally standardized test protocols for toxicity screening of dental materials in line with the existing standards (ISO 10993 - series) are clearly needed to obtain comparable results.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

Top Level Search