Evaluation of the Transverse Strength and UV Spectrophotometric Analysis of the Residual Monomer Content of Autoclave Polymerized Conventional and High-Impact Heat-Cure Denture Base Resins—An In-Vitro Study

Background and Objective: Inspite of advancements in material properties of heat cure acrylic resin, fracture of denture base and allergic reactions due to release of residual monomer is encountered frequently. To improve strength and to reduce residual monomer, different polymerization methods need to be investigated. The objective is to evaluate and compare transverse strength and residual monomer content of two different heat cured denture base resins polymerized by conventional water bath and by autoclave. Materials and Methods: Samples were prepared with Acralyn-H conventional heat cure resin and Acralyn-H super hi-impact resin using metal dies. Samples undergoing water bath polymerization were polymerized in water bath at 74°C for 2 hours followed by 100°C for 1 hour and samples undergoing autoclave polymerization were cured in an autoclave at 121°C and 210 kPa for 30 minutes as holding temperature. Transverse strength specimens were processed and then tested for transverse strength in a Universal testing machine. Specimens for residual monomer content estimation were weighed and each specimen’s residual monomer was extracted in methanol using Soxhlet extractor and then read at 230nm in Ultraviolet-Visible spectrophotometer. Concentrations of residual monomer were evaluated and weight fractions were calculated. Results: The results of this study showed a statistically significant difference in transverse strength of Acralyn-H conventional heat cure resin polymerized by autoclave, whereas all other groups showed a non-significant result. Conclusion: Autoclave can be used as an alternative polymerization technique as it has shown similar results when compared with water bath polymerization and the time required for polymerization was also reduced.