Objectives: It has recently been shown by our group that cell culture toxicity data are highly model dependent. The aims of the present study were to establish a cytotoxicity test for dental composites according to ISO 10993, optimize this test protocol for dental composite materials and to compare the cytotoxicity of dental composite materials applied in 2.5 or 5 mm increments. Methods: According to ISO 10993, composite specimens (Definite, Herculite XRV and Solitaire 2) were incubated with L929 fibroblasts for 72h and cell numbers determined by flow cytometry. The effects of varying the specimen area to cell surface layer area ratio, transparency of specimen moulds, passage number of cultured cells, cell culture medium and experimental personnel were investigated. This optimized assay was further modified to test dental composites (Definite, InTen-S, Prodigy condensable and Solitaire 2) with different increment thickness (2.5 mm or 5 mm). In all protocols, specimens were added to cultures immediately following production or after preincubation for 7 days or 6 weeks under cell culture conditions. Results: Herculite XRV specimens (covering approximately 10% of cell surface layers according to ISO 10993-5) were severely cytotoxic even after 6 weeks preincubation whereas fresh Herculite XRV (approximately 2% cell surface layer coverage) showed only moderate cytotoxicity which diminished with increasing preincubation times. In this test system, Solitaire 2 showed severe and persistant cytotoxicity, whereas Definite was the least cytotoxic. The cytotoxicity of every composite was significantly higher when polymerized in 5 mm increments as opposed to 2.5 mm increments (p<0.0001) where Solitaire 2 showed the highest cytotoxicity, followed by InTen-S, Prodigy condensable and Definite. Conclusion: Cytotoxicity tests should be optimized and internationally standardized so that screening of dental materials is in line with existing standards allowing toxicity risk assessment.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the 81st General Session of the International Association for Dental Research (June 25-28, 2003)

Top Level Search