Synthesis and Characterization of Dimethacrylate Monomer with High Molecular Weight for Root Canal Filling Materials

A new dimethacrylate monomer 9,9'-bis[4-(2'-hydroxy-3'-methacryloyloxy- propoxy)phenyl] fluorene ( 3 ) with a molecular weight of 634 was synthesized in 51.4% yield by addition of a glycidyl ether group to 9,9'-bis(4-hydroxyphenyl) fluorene ( 1 ) by the reaction of compound 1 with epichlorohydrin, and then introducing the methacrylate moiety by the reaction of the epoxy group with methacrylic acid. The structure of monomer 3 was confirmed by FT-IR, 1 H-NMR, mass spectra and elemental analysis. Keywords: Dimethacrylates, high molecular weight, synthesis, characterization. Introduction Polymethyl methacrylate was firstly used in tooth restoration by German scientists in 1937. After that polymethacrylates were used extensively as dental materials, e.g. as dental restorative materials and primary resins of root canal sealers in root canal treatment, due to their good biocompatibility and adhesive properties [1]. The main drawback of methacrylate monomers is volumetric shrinkage during their polymerization, so marginal gaps between tooth and sealer, lead microleakage and clinical failure when these monomers were applied in root canal sealers are unavoidable. In order to decrease the polymerization shrinkage of methacrylate monomers, Bowen [2] had synthesized Bis-GMA with a