Effect of Different Surface Treatments on the Surface Roughness and Gloss of Resin-Modified CAD/CAM Ceramics

The purpose of this in vitro study is to compare the roughness and gloss of four resin-modified CAD/CAM ceramics after different surface treatments. Forty-eight specimens (1.20 x 12 mm(2)) were prepared from Lava Ultimate (LU), Vita Enamic (VE), Cerasmart (CS), and Crystal Ultra (CU) CAD/CAM ceramics. The prepared specimens were polished with silicon carbide paper before being roughened with a 30 mu m grit diamond bur. Each material was allocated into four groups: control (no treatment), Luster Meisinger polishing (MP), Optiglaze (OG), or Meisinger polishing, followed by a final polishing with Shofu Direct Dia Paste (MP+PP). The roughness and gloss were measured after the surface treatment using a profilometer and gloss meter, respectively. Scanning electron microscopy micrographs were obtained to analyze the surface characteristics. Statistical analysis was performed using a multivariate analysis of variance (MANOVA), one-way ANOVA, and Dunnett's post hoc test (alpha = 0.05). The surface treatments significantly affected the surface roughness and gloss of the tested materials (p < 0.05). All the tested resin-modified CAD/CAM ceramics demonstrated a lower surface roughness and higher gloss after glazing using OG, followed by MP+PP and MP. The highest and lowest Ra were presented by the control VE (0.63 +/- 0.23 mu m) and glazed LU specimens (0.04 +/- 0.01 mu m), respectively. The highest and lowest GU were presented by the glazed LU (90.48 +/- 4.69 GU) and the control VE specimens (23.32 +/- 2.41 GU), respectively. After clinical adjustment, finishing, and polishing, the restoration is essential to obtain a restorative surface with lower roughness and the highest gloss. Surface glazing using Optiglaze exhibited the smoothest and glossiest surface of all the tested resin-modified ceramics.