Effect of glass fibre reinforcement on residual methyl methacrylate content of denture base polymers

Objectives. Residual methyl methacrylate (MMA) content in unreinforced and in glass fibre reinforced, heat-polymerized (long- and short-term terminal boiled and conventionally) autopolymerized (at room temperature and in water at 60 °C) and microwave-polymerized (3 min at 500 W) denture base polymers after processing were compared. Methods. Ten specimens were prepared for each curing cycle (five unreinforced and five reinforced) adding up to a total of 60. Residual MMA content was determined using high-performance liquid chromatography. Data were analysed with one-way ANOVA followed by Tukey HSD and Paired Samples tests. Results. For unreinforced and reinforced groups; residual MMA content succesively ranked from lowest to highest in; long- and short-term terminal boiled heat-polymerized, microwave-polymerized, autopolymerized specimens processed in water at 60 °C and conventionally heat- and autopolymerized specimens processed at room temperature. Generally residual MMA was found more in glass fibre reinforced test groups than unreinforced groups. However, when reinforced residual MMA increased significantly in long- and short-term terminal boiled heat- (P<0.05) and microwave-polymerized test groups (P<0.01). Conclusions. Although this increase was significant, lowest residual MMA content was found succesively in reinforced long- and short-term terminal boiled heat-polymerized and microwave-polymerized like in unreinforced groups.