Comparative evaluation of color stability in polished and glazed CAD/CAM ceramics subjected to coffee thermal cycling: an in vitro study.

BACKGROUND AND AIMS: Optimal color stability is crucial for patient satisfaction in prosthetic dentistry. This study assessed the impact of coffee immersion on the color stability and translucency of polished and glazed lithium disilicate, zirconia, and zirconia-reinforced lithium disilicate ceramics.

MATERIALS AND

METHODS

This in-vitro study evaluated the color stability and translucency of three CAD-CAM ceramics: lithium disilicate (IPS e.max CAD), monolithic zirconia (Incoris ZI), and zirconia-reinforced lithium disilicate (Vita Suprinity). Ninety specimens (30 per ceramic type) were divided into glazing, polishing, and control groups. After thermal cycling in a coffee solution, color changes (ΔE) and translucency parameters (TP) were measured with a spectrophotometer. ANOVA was used to analyze differences between groups. Post-hoc comparisons were conducted using the Tukey test, with a significance threshold of p < 0.05.

RESULTS

The results showed no significant differences in color changes (ΔE) between the polished, glazed, and control groups after coffee immersion (P = 0.096). Although coffee immersion caused detectable color changes, these were not clinically perceptible (ΔE > 1.01). Translucency (TP) measurements revealed significant differences between the groups (P < 0.001), with monolithic zirconia showing lower translucency compared to the other ceramics.

CONCLUSION

This in-vitro study showed that coffee immersion negatively impacted the color of all tested CAD-CAM ceramics, although the changes remained within clinically acceptable limits. Surface treatments, including polishing and glazing, had no significant effect on the color stability or translucency of the ceramics. Coffee immersion also did not affect translucency.