Effect of accelerated aging on the color stability of feldspathic ceramic treated with various surface treatments

Objective: To investigate the effect of the accelerated aging process on the color stability of feldspathic ceramic treated with dual ion exchange, overglaze, polishing, and autoglaze surface treatments. Method and Materials: A total of 40 disks (15 mm in diameter and 2 mm thick) of feldspathic ceramic were made in an A2 shade according to the manufacturer's recommendations. The samples were randomly divided into 4 groups: dual ion exchange, overglaze, polishing, and autoglaze. The samples were subjected to conditions in an accelerated aging machine for 150 and 300 hours. Differences in color before and after accelerated aging were calculated using spectrophotometric analyses. Overall color difference (ΔE) was determined using the CIE L*a*b* system for measuring small color differences. Scanning electron microscopy was used to evaluate the surface texture of samples. Color difference data were evaluated statistically by Kruskal-Wallis and Mann-Whitney U tests, with a significance level of .05. Results: After 150 and 300 hours of accelerated aging, color changes of the 4 surface treatment groups ranged between 0.35 and 1.31 ΔE units. All ΔE values were below a quantitative level that would be considered clinically acceptable. Autoglazed samples were the most color stable, followed by ion exchanged, overglazed, and polished test samples. Conclusions: All groups demonstrated color stability below a quantitative level that would be considered clinically acceptable, but long-term clinical studies are necessary to verify these findings. Parole chiave: aging, ceramics, color change