Effect of carbamide peroxide bleaching agent on the surface roughness and gloss of a pressable ceramic.

OBJECTIVE: This study evaluated the influence of carbamide peroxide, 10% and 16%, on the surface roughness and gloss of a pressable ceramic. MATERIALS AND METHODS: Carbamide peroxide (10% or 16%) was applied for 4 hours or 3 hours per day for 14 days, respectively, in pressable ceramic discs (14 mm x 2 mm). Specimens were stored in distilled water at 37 degrees C. Surface roughness and gloss were determined before carbamide peroxide application (T(0) ), 7 days (T(7) ) and 14 days (T(14) ) after the initial treatment. ANOVA was used with repeated measures and multiple comparisons with a Bonferroni adjustment (P < 0.005). RESULTS: Significant increase in surface roughness was observed over time (P < 0.001), with T(0) < T(7) < T(14) . When the gloss was analyzed, significant differences were found (P < 0.001), control group showed a higher gloss than those of the 10% and 16% groups. Significant decrease in gloss was observed over time (P < 0.001), with T(0) > T(7) > T(14) . CONCLUSIONS: The surface roughness of pressable ceramics increased, while their gloss significantly decreased when 10% or 16% carbamide peroxide was applied. The specimens treated with 16% carbamide peroxide exhibited higher surface roughness and less gloss than the specimens treated with 10% carbamide peroxide. CLINICAL SIGNIFICANCE: This study found that carbamide peroxide gels commonly used in at-home procedures influenced the surface roughness and gloss of a pressable ceramic that is often used for rehabilitation esthetics.