The impact of tooth brushing simulation and staining thermocycling on surface roughness and color stability of CAD/CAM laminate veneers ceramic materials: an in-vitro study

Abstract This study investigated the influence of simulated brushing and staining thermocycling on surface roughness and color stability of different types of CAD/CAM laminate veneers ceramic materials. Forty-eight square-shaped specimens were created using two types of CAD/CAM glass ceramics ( ALDS , CEREC Tessera, Dentsply Sirona, and ZLS , Vita Suprinity, Vita Zahn Fabrik), each material group was divided into two subgroups ( N = 12) according to surface finishing protocols. Surface roughness (Ra) and color parameters were measured initially, after 6 months and 1 year of brushing simulation and Coffee/Tobacco thermocycling. Data was collected and statistically analyzed using Wald-type ANOVA, and post-hoc simple effects of estimated marginal means were compared using Wald tests with Sidak adjustment. For surface roughness, all the main effects and their interactions were not statistically significant, according to ANOVA ( P > 0.05). Color change results (∆E) showed that after one year of tooth brushing simulation and C/T thermocycling, Tessera finished subgroup had a significantly higher mean value (16.95 ± 3.06) than Vita Suprinity finished subgroup (6.67 ± 1.85) ( p < 0.001), and the effect size was large, 0.51. While Tessera glazed subgroup had a higher non-significant mean value (7.03 ± 0.64) than Vita Suprinity glazed subgroup (6.06 ± 2.34), ( p = 0.188), and the effect size was small, 0.02. All tested ceramics showed acceptable surface roughness values; however, tooth brushing combined with C/T thermocycling caused discoloration especially in finished Tessera CAD/CAM materials. The color change (∆E) of the two laminate veneer materials, under different surface treatments, exceeded the clinically acceptable range.