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.
Highlights
Dental Composites known as “white filling materials” typically consist of a resin based oligomer matrix such as Bisphenol A glycidyl methacrylate (Bis-GMA) or Urethane Dimethacrylate (UDMA), and inorganic fillers such as Silicone dioxide (Silica)
Our study aimed to study the effect of short and medium term aging immersion (48 hours, 1 month, 2 months and 4 months) of the varying concentrations (0.01%, 0.6%, 1.00% and 1.40%) of Bisphenol-A-glycidyl dimethacrylate and determine if this immersion had an effect on the flexural strength and elastic modulus
The dental resin composite was synthesized in the composition that is common to materials on the market for clinical use
Summary
Dental Composites known as “white filling materials” typically consist of a resin based oligomer matrix such as Bisphenol A glycidyl methacrylate (Bis-GMA) or Urethane Dimethacrylate (UDMA), and inorganic fillers such as Silicone dioxide (Silica). The advantages of Bis-GMA over other monomers are less shrinkage, higher modulus, and reduced toxicity due to its lower volatility and diffusivity into tissues (Sideridou et al, 2002). In dentistry it is used in resin-based sealants, which serves to form a protective coating or a barrier that isolates pits and fissures to help prevent caries in children and adults. The free radical polymerization of the monomer is initiated and this is accompanied by a cross-linking of the molecule, which results in polymerization shrinkage. The internal stresses created within the material can be transferred to the www.ccsenet.org/jmsr
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