Effects of ultrasonic scaling on the optical properties and surface characteristics of highly translucent CAD/CAM ceramic restorative materials: An in vitro study

Esthetic restorations using highly translucent ceramics powered by chairside digital dentistry are becoming popular. The purpose of this in vitro study was to investigate the impact of ultrasonic scaling on the optical and surface properties of highly translucent ceramic materials for digital dentistry. A resin nanoceramic (Lava Ultimate; LU), dual-network ceramic (Vita Enamic; VE), feldspathic ceramic (Vitablocs Mark II; VM), lithium disilicate ceramic (IPS e.max CAD; EX), and high-translucency monolithic zirconia (Rainbow Shine-T; MZ) were evaluated. All specimens were subjected to ultrasonic scaling, and the following data were obtained before and after scaling: color change (ΔE00), translucency parameter, surface gloss, surface roughness, and superficial topography. One-way analysis of variance (ANOVA), repeated-measures ANOVA, and two-way ANOVA were used for intergroup comparisons (all α = 0.05). The mean ΔE00 values were 0.243, 0.48, 1.591, 0.143, and 4.466 for LU, VE, VM, EX, and MZ, respectively, with statistically significant differences among the materials. With regard to Commission Internationale de l'Éclairage (CIE) L*, a*, and b* values, VE, VM, and MZ showed significantly decreased L* values relative to the baseline values. Moreover, MZ showed a significantly increased a* value and a significantly decreased b* value after scaling. Ultrasonic scaling also resulted in significant changes in the surface gloss of the LU, VE, VM, and MZ specimens. Micrographs showed scrapes and surface deterioration after scaling. For all materials, the translucency parameter and the surface roughness showed no significant differences between specimens that were subjected to scaling and those that were not. These findings suggest that ultrasonic scaling MARKEDLY affects the optical properties and surface characteristics of highly translucent computer-aided design and computer-aided manufacturing (CAD/CAM) ceramics. The findings can aid restorative dentists in the selection of appropriate materials and motivate periodontists for performing scaling procedures with due consideration of restorations in esthetically demanding areas.