The Effect of Inhibitor Concentrations on the Chemical and Mechanical Properties of Bis-GMA-Based Resin Dental Composites

Abstract

Bis-GMA (Bisphenol A glycidyl methacrylate) based resin composites in dentistry require UV induced light polymerization to be used as restorative materials. This polymerization induces shrinkage stresses on command light polymerization, which can be clinically significant. To resolve this issue inhibitors such as Bisphenol-A-glycidyl dimethacrylate (BHT) have been introduced as an alternative method to try to decrease this polymerization shrinkage. However increases in inhibitor concentration whilst reducing polymerization shrinkage might induce an effect on the mechanical properties of the resin composite. In addition, the oral cavity is a fluid environment and can induce changes in the resin composite. The aim of this study was to try to determine if an increase in inhibitor concentration had an effect on the flexural strength and elastic modulus of resin composites after short and medium term aging immersion. These assessments were accomplished by looking at Flexural Strength and Elastic Modulus after short and medium term aging immersion. An experimental composite was prepared using a blend of Bisphenol A glycidyl dimethacrylate (Bis-GMA): Urethane Dimethacrylate (UDMA): Triethylene glycol dimethacrylate (TEGDMA) (1:1:1 weight ratio) with 70 wt% silanized glass fillers. Four group concentrations of BHT were tested mechanically using flexural strength and elastic modulus. Based on this laboratory study, changes in BHT concentrations can induce and maintain high strength in resin composites.