Abstract
Objectives. The currently available commercial dental resin composites have limitations in use owing to the high viscosity and water sorption of Bisphenol A glycidyl methacrylate (BisGMA). The objective of this study was to obtain a BisGMA analog with reduced viscosity and hydrophilicity for potential use as an alternative to BisGMA in dental resin composites. Methods. The targeted chlorinated BisGMA (Cl-BisGMA) monomer was synthesized via the Appel reaction. The structural modification was confirmed via H-1- and C-13 nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and mass spectrometry. Five resin mixtures (70:30 wt. %: F1=BisGMA/TEGDMA; F2 = Cl-BisGMA/TEGDMA; F3 = Cl-BisGMA only; F4 = Cl-BisGMA/BisGMA; F5 contained 15% TEGDMA with equal amounts of BisGMA and Cl-BisGMA) were prepared. The viscosity, degree of double-bond conversion (DC), water sorption (W-SP), and solubility (W-SL) were tested. Cell viability and live/dead assays, as well as cell attachment and morphology assessments, were applied for cytotoxicity evaluation.
Results. Cl-BisGMA was successfully synthesized with the viscosity reduced to 7.22 (Pas) compared to BisGMA (909.93, Pa s). Interestingly, the DC of the F2 resin was the highest (70.6%). By the addition of equivalence concentration of Cl-BisGMA instead of BisGMA, the WSP was decreased from 2.95% (F1) to 0.41% (F2) with no significant change in WSL. However, the WSL increased with high Cl-BisGMA content. Biological tests revealed that all the resins were biocompatible during CL1 incubation.
Significance. The experimental resins based on Cl-BisGMA exhibited improved properties compared with the control samples, e.g., biocompatibility and lower viscosity, indicating that Cl-BisGMA can be considered as a potential monomer for application in dental resin composites. (C) 2019 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.