Synthesis and evaluation of novel dental monomer with branched aromatic carboxylic acid group

Abstract

A new glycerol-based dimethacrylate monomer with an aromatic carboxylic acid, 2-((1,3-bis(methacryloyloxy)propan-2-yloxy)carbonyl)benzoic acid (BMPB), was synthesized, characterized, and proposed as a possible dental co-monomer for dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA) and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (BisGMA) in addition to BMPB were formulated with water at 0, 5, 10, and 15 wt % to simulate wet, oral conditions, and photo-polymerized. Adhesives were characterized with regard to viscosity, real-time photopolymerization behavior, dynamic mechanical analysis, and microscale 3D internal morphologies and compared with HEMA/BisGMA controls. When formulated under wet conditions, the experimental adhesives showed lower viscosities (0.04–0.07 Pa s) as compared to the control (0.09–0.12 Pa s). The experimental adhesives showed higher glass transition temperature (146–157°C), degree of conversion (78–89%), and rubbery moduli (33–36 MPa), and improved water miscibility (no voids) as compared to the controls (123–135°C, 67–71%, 15–26 MPa, and voids, respectively). The enhanced properties of these adhesives suggest that BMPB with simple, straight-forward synthesis is a promising photocurable co-monomer for dental restorative materials.