Synthesis and characterization of new dimethacrylate monomer and its application in dental resin

In this study, a dimethacrylate monomer, 1,4-Bis[2-(4-(2'-hydroxy-3'-methacryloyloxy-propoxy)phenyl)-2propyl]benzene (BMPPB) was synthesized to replace 2,2-bis[4-(2'-hydroxyl-3'-methacryloyloxy-propoxy)phenyl]propane (Bis-GMA) as one component of dental restorative materials. The structure of BMPPB and its intermediate product 1,4-bis[2-(4-(oxiranylmethoxy)phenyl)-2propyl]benzene (BOPPB) were confirmed by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance spectroscopy ((1)H-NMR), and elemental analysis. In order to evaluate the possibility of replacing Bis-GMA with BMPPB in dental resin, double bond conversion (DC), polymerization shrinkage, contact angle, water sorption (WS) and solubility (SL), and flexural strength (FS) and modulus of BMPPB/tri(ethylene glycol)dimethacrylate (TEGDMA) (50/50 wt) resin system and Bis-GMA/BMPPB/TEGDMA (25/25/50 wt) resin system were studied. Commercially used Bis-GMA/TEGDMA (50/50 wt) dental resin system was used as reference. The results showed that BMPPB-contained copolymer had higher DC, higher WS and SL than the copolymer that only contained Bis-GMA (p<0.05). All of the copolymers had nearly the same contact angle (p>0.05). BMPPB/TEGDMA resin system had lower polymerization shrinkage, higher FS and modulus (p<0.05) than Bis-GMA/TEGDMA resin system. There was no significant difference on polymerization shrinkage, FS and modulus (p>0.05) between Bis-GMA/BMPPB/TEGDMA resin system and Bis-GMA/TEGDMA resin system. Before and after water immersion, both FS and modulus of every copolymer did not change significantly (p>0.05). Therefore, BMPPB had potential to be used to replace Bis-GMA as base resin in dental restorative materials, but many studies should be undertaken further.