Effect of bleaching materials on optical properties and surface roughness of discolored dental ceramics

Successful restorative treatment depends on aesthetic, mechanical, and biological properties. This study aimed to evaluate the effect of Hydrogen Peroxide and Sodium Perborate on surface roughness and stain removal from stained ceramics. Thirty-two discs were prepared of feldspar (diameter 6.4 ± 0.2 mm, thickness 2.2 ± 0.1 mm). and lithium desilicated glass ceramic )diameter 7 ± 0.1 mm, thickness 2.2 ± 0.1 mm). Specimens were divided into four groups, based on the type of porcelain and bleaching agent used (n = 8). All the Specimens were immersed in (tea, yogurt, soda, orange juice, and Mulberry juice) respectively for 30 days. Then Hydrogen Peroxide 30% was applied to specimens for 2 h. Sodium Perborate was applied for 14 days/6 hours per day. CIEDE2000 parameters and surface roughness values were recorded at three times; initial baseline color, post staining, and post bleaching. Data were statistically analyzed using paired t-test and ANOVA. There was no significant difference in color changes (∆E₀₀2) and roughness changes values between all groups, but there was a significant increase in surface roughness in each group after staining and after bleaching. Also, the residual color values of all groups were below 1.8, with lithium disilicate ceramic treated with sodium perborate showing better color retrieval. Conclusion the bleaching agents reduced color change caused by discoloring solutions and caused an increase in surface roughness.