THERMAL, MECHANICAL, AND BIOCOMPATIBILITY PROPERTIES OF CURED MULTI-METHACRYLATES DERIVED FROM PROPOXYLATED, ENZYME OLIGOMERIZED BPA NEAT RESINS

Abstract

In a previous study, we showed that the methacrylate derivatives of propoxylated bisphenol-A oligomers (EPBPA) have potential application for formulating visible light-curable (VLC) composites for dental restoratives. The purpose of this study was to evaluate the thermal, mechanical and biocompatibility properties of the EPBPA oligomers. The EPBPA oligomer multi-methacrylate: triethylene glycol dimethacrylate (TEGDMA) (50:50/wt:wt) blends were combined with 0.5 wt% camphorquinone (CQ) and 1.0 wt% N,N-di-methyl-aminoethyl methacrylate (DMAEMA). The control was 2,2-bis[4-(2-hydroxy-3-methacryloyloxpoxy) phenyl] propane (BisGMA:TEGDMA) (50:50/wt:wt) blends having the same levels of CQ/DMAEMA. The glass transition temperature (Tg) and the thermal expansion coefficient (α) were obtained for all materials studies, using a thermomechanical analyzer (TMA, TA Instruments 2940 with an expansion probe (heating rate 10°C/min, N2). The compressive (CS) and diametral tensile strength (DTS) tests were carried out using a screw-driven mechanical testing machine (Model 4204 screw-driven mechanical testing machine (Model 4204, Instron Corp., Canton, MA) at 25°C, with a constant crosshead speed of 0.5 mm/min. The biocompatibility test of the polymerized oligomers (EPBPA) was done, and compared with the conventional BisGMA/TEGDMA neat resins and blank controls, using cellculture techniques. Human gingival fibroblasts were used for the initial evaluation of the biocompatibility of the EPBPA based resins. One-way ANOVA and Tukey multiple comparison (p < 0.05) results show that the cured EPBPA neat resins have better thermal and mechanical properties than the BisGMA/TEGDMA neat resin control. The results also revealed that the EPBPA oligomer significantly favored the cell growth of the human gingival fibroblasts, compared to the control. Thus, the conclusion is reached that EPBPA oligomers have potential application in formulating dental composites as direct esthetic restorative materials with improved properties.