Evaluation of the influence of different polymerization methods on rest monomer amount and cytotoxicity in the acrylic resins reinforced with glass fibers

The purpose of this study was to investigate the residual monomer amount and cytotoxicity of glass fiber reinforced and unreinforced acrylic resin materials polymerized with different polymerization methods in vitro.E-glass fiber reinforced and unreinforced acrylic resin specimens were prepared with four different polymerization methods (heat-polymerized, autopolymerized, microwave polymerized, gamma-ray polymerized). Residual MMA content was determined using high-performance liquid chromatography. The cytotoxicity of acrylic resin test specimens evaluated with L929 mouse fibroblast cell culture. Cell viability was determined at 24, 48, 72, and 96 h after exposure by MTT method. Results were analysed with one-way ANOVA followed by Tukey HSD and Mann-Whitney U test.The highest residual monomer content between reinforced and unreinforced groups was found in autopolymerized specimens. The lowest residual monomer contents were in microwave polymerized unreinforced groups and heat polymerized reinforced groups. Generally, reinforcement with fiber increased the residual monomer amount. This amount of increase were significant statistically (p<0.05).In each incubation period, most toxic group was autopolymerized unreinforced resin. In 24, 48, 72h incubation period minimal toxic group was heat polymerized. However, this incubation periods were not found statistically different for polymerization methods. Microwave polymerized group showed the lowest toxicity at 96h. The correlation between microwave polymerized group with most cell viability and autopolymerized group with lowest cell viability at 96h were found statistically significant (p<0.05).There was no significance in polymerization methods between reinforced groups statistically. However, the highest toxicity degree was in autopolymerized resin in all incubation periods. The lowest toxicity degrees at 24 and 72h were in microwave polymerized group and at 48 and 96h were in heat polymerized group. Fiber reinforcement process decreased the cell viability percentage in general. However, this change in decrease was not statistically significant.As a result, reinforcement with glass fiber increased the residual monomer amount and cytotoxicity in acrylic resin specimens.