Effects of Different Whitening Toothpastes on the Color of Aged Zirconia-Reinforced Lithium Silicate Ceramics After Immersion in an Acidic Beverage.

INTRODUCTION: This study is aimed at comparing the effects of different whitening toothpastes on the color of aged ZLS ceramics after immersion in an acidic beverage. MATERIALS AND METHODS: In this in vitro study, 72 cylindrical (2×10 mm) ZLS ceramic specimens were sintered, polished, and randomly assigned to six groups (n = 12) of distilled water (D), distilled water + Colgate Total Whitening (DT), distilled water + Perfect White black (DP), cola (C), cola + Colgate Total Whitening (CT), and cola + Perfect White black (CP). After 5000 thermal cycles, the specimens were immersed in an acidic beverage for 6 days. The specimens in groups CP, CT, DP, and DT were brushed at 40 rpm for 2.33 min. The CIEL ∗a ∗b ∗ color parameters were measured spectrophotometrically before and after aging and toothbrushing. Data were analyzed by one-way ANOVA (alpha = 0.05). RESULTS: The color change (ΔE) was not clinically detectable in any group (< 3.3). ΔE of the CT group was significantly greater than that of the C (mean difference: 0.12, p < 0.05) and the CP (mean difference: 0.13, p < 0.05) groups. ΔL of the C group was significantly greater than that of the CP group (mean difference: 0.21, p < 0.05). The differences in Δa and Δb were not significant among the groups (p > 0.05). CONCLUSIONS: The application of Colgate Total Whitening and Perfect White black toothpaste for 6 weeks, along with simulated 6-month cola consumption, did not cause a clinically detectable change in the color of aged ZLS ceramics.