Abstract
BACKGROUND: Glazing enhances both the aesthetics and functionality of zirconia restorations by creating a smooth, glassy surface. The traditional glazing method involves powder and liquid, but newer spray and paste techniques have been developed to simplify the process and improve efficiency. This study evaluated the effects of different glazing methods on the surface roughness and hardness of monolithic translucent zirconia ceramics. METHODS: Thirty highly translucent, pre-shaded (XTCERA SHT, Shenzhen Xiangtong Co., Ltd., China) zirconia samples, with shade A3 (12 × 10 × 2 mm), were divided into three groups based on the glazing method (n = 10): Group 1 (glazed using powder and liquid), Group 2 (glazed with paste), and Group 3 (glazed with spray). After glazing, each group was further divided into two subgroups (n = 5): Subgroup A (non-corroded samples) and Subgroup B (corroded samples). Corrosion was induced by immersing Subgroup B samples of each group in 4% acetic acid, while Subgroup A samples were immersed in distilled water. Then all samples were tested for surface hardness and roughness. Surface hardness was measured using a Vickers diamond indenter, while surface roughness was assessed using a non-contact optical profilometer (U500x Digital Microscope, Guangdong, China) with WSxM analysis software. After testing, data were analyzed for normality using the Shapiro-Wilk test. Quantitative data were expressed as mean ± standard deviation (SD), with comparisons made using the t-test and one-way ANOVA (P ≤ 0.05). RESULTS: Hardness results revealed that there were no significant differences before and after corrosion for any group, Group 1 (p = 0.977), Group 2 (p = 0.969), and Group 3 (p = 0.857), whereas surface roughness testing showed a significant increase in roughness postcorrosion, with Group 1 differing significantly from Group 2 (p = 0.034) and Group 1 from Group 3 (p = 0.038). CONCLUSION: The type of glazing method (powder and liquid, paste, or spray) did not significantly affect the hardness of zirconia ceramics. However, the powder and liquid method resulted in a smoother surface, particularly after corrosion.