Effects of ageing and staining on color of acrylic resin denture teeth

Objectives: To assess the color stability of high-strength acrylic resin denture teeth after exposure to red wine, coffee and artificial ageing.

Methods: Four different shades of acrylic resin denture teeth were selected from three manufacturers. The teeth were evaluated in two phases: Phase I, upon staining for 7 days in distilled water (control Group A), red wine (experimental Group B) and coffee (experimental Group C), and Phase II, upon artificial ageing in a Weather-Ometer for a total exposure of 150 kJ/m(2) (control Group A; Phase I). Denture tooth positioning jigs were fabricated and color data recorded by means of an intra-oral spectrophotometer and expressed using the Commission Internationale d'Eclairage (CIE) L*a*b* color notation system. Means and standard deviations were determined. The staining data were analysed by three-way ANOVA, while the artificial ageing data were analysed by two-way ANOVA. Fisher's PLSD intervals were calculated at a significance level of P ≤ 0.05.

Results: In the staining experiment, the main effects of stains and denture teeth and the two-way and three-way interactions among stains, denture teeth and shades were significant (P ≤ 0.05). The same was true for the main effects of denture teeth and shades and their interactions in the ageing experiment. The smallest overall color change upon staining in red wine was recorded for Vita Physiodens denture teeth (ΔE*=0.9 ± 0.4), followed by SR Vivodent PE 1.2 (0.6) and Portrait IPN 2.4 (0.6). Corresponding values for staining in coffee were 2.0 (0.6), 1.7 (1.0) and 1.8 (0.8), while ageing-dependent changes in color were 1.7 (0.4), 2.4 (0.8) and 1.1 (0.4) for Portrait IPN, SR Vivodent PE and Vita Physiodens teeth, respectively.

Conclusion: Although the null hypothesis has been partially rejected, because some statistically significant changes in color and color coordinates occurred upon staining and ageing, all evaluated denture teeth exhibited good color stability compared to the 50:50% acceptability threshold used in data interpretation.

Clinical significance: Selection of a color stable and stain-resistant denture tooth can contribute to denture longevity and overall patient satisfaction.