The Influence of Thermal Curing Cycles on the Color Stability of Unfilled Polymethyl Methacrylate Teeth

Purpose: The purpose of this study was to evaluate the influence of water bath polymerization cycles on the color stability of unfilled polymethyl methacrylate (PMMA) teeth. Materials and methods: A total of 72 samples of unfilled PMMA were divided into two groups. Group 1 was subjected to a short curing cycle and group 2 to a long thermal curing cycle. Color measurements were done using a spectrophotometer and evaluated by the Commission Internationale de l’Eclairage (CIE) L*a*b* color system. Color difference (∆E) was calculated before and after thermal curing cycles and the data were statistically analyzed. Results: Group 2 teeth exhibited the highest ΔE values and color change to long curing cycle with significant difference between them. Conclusion: All the ΔE values were below 3.3, indicating that the color changes are not clinically perceptible.