Effect of polymerization methods and thermal cycling on color stability of acrylic resin denture teeth

Abstract

Statement of problem: Acrylic resin denture teeth are widely used due to the chemical bond to the acrylic resin of the denture base. However, discoloration of acrylic resin denture teeth can be a problem. Purpose: The purpose of this study was to investigate the effect of polymerization methods and thermal cycling on the color change of acrylic resin denture teeth. Material and methods: Ten different brands of acrylic resin denture teeth were evaluated: Art Plus (AP), Biolux (BX), Biotone IPN (BI), Magister (MG), Mondial 6 (MD), Premium 6 (PR), SR Vivodent PE (SR), Trilux (TR), Trubyte Biotone (TB), and Vipi Dent Plus (VP). Each brand was divided into 2 groups (n=12); each group was subjected to 1 of 2 polymerization methods (microwave, 500 W for 3 minutes, or water bath, 74°C for 9 hours). After polymerization, all of the specimens were thermal cycled between 5°C and 55°C with 30-second dwell times for 5000 cycles. The specimen colors were measured with a spectrophotometer, using the CIE L*a*b* system, at baseline (B), after polymerization (P), and after thermal cycling (T). Color differences (ΔE) were calculated for periods between P and B (PB), T and B (TB), and T and P (TP). A ΔE of ≤3.3 was considered clinically acceptable. The data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (α=.05). Results: The highest ΔE values were obtained for BI and SR teeth; these were significantly higher than the values obtained for the other brands (P<.05). There was no significant difference between the 2 polymerization methods. There was no significant difference between TB and PB for either polymerization method. Conclusions: The ΔE values are within acceptable clinical limits for all brands, for both polymerization methods and different measurement periods. © 2009 The Editorial Council of the Journal of Prosthetic Dentistry.