Biocompatibility (MTT Test) of New, Non-Bis-GMA-Based Composites

Objectives: To evaluate/compare biocompatibility among new, non-Bis-GMA-containing composites, conventional composites, and a resin modified glass ionomer.
Methods: Cylindrical specimens (5x2mm) were made in opaque molds. Light-cured (LC) specimens were exposed from the open end (20 Sec, Elipar S10, 3M ESPE; 20s Demi Ultra for PREMISE), and self-cure (SC) specimens were allowed to polymerize at room temperature. Materials tested: non-Bis-GMA-Based composites (ACTIVA KIDS (SC and LC), Pulpdent, and ADMIRA FUSION (VOCO); conventional Bis-GMA-based composite (PREMISE, Kerr Dental); Resin modified glass ionomer (RMGI) (FUJI II LC, GC America). Specimens were removed from molds and dark-stored 24h. Polymerized specimens were then placed in medium (Hams Complete) for 24h, after which the eluate was placed on mouse fibroblasts (L929) for 72h. Recovered specimens were placed into phosphate-buffered saline and were dark-stored at 37°C for 1wk. Eluates were obtained and applied to new L929 cells and incubated at 37°C for 24h (1wk specimens). The process was continued to obtain 3-week old eluate results. Similar-sized Teflon cylinders were tested as control. N=6/product. Cell mitochondrial succinate dehydrogenase (SDH) activity (MTT testing) was measured on cultures after each time frame, and individual plate well results were expressed as a percentage of the Teflon controls. Within a material, percent control values were compared using a 1-way, repeated measures ANOVA. Within a time period, percent control values were compared using a 1-way ANOVA. Post-hoc testing by the Tukey test. Pre-set alpha=0.05.
Results: Table presents results. Products demonstrated significant improvement in biocompatibility (higher percent control) with time. At 24h, all products, except ADMIRA and PREMISE, showed low biocompatibility. After 1wk, biocompatibility for the RMGI greatly increased. After 3wk, all products, except ACTIVA KIDS LC, demonstrated similar SDH activity as Teflon controls, or better.
Conclusions: Biocompatibility of all materials improved with time, and varied among products: not all non-Bis-GMA-Based composites react similarly.