Effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics

Abstract Statement of problem Surface polishing or glazing may increase the appearance of depth of monolithic zirconia restorations. Purpose The purpose of this in vitro study was to investigate the effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics. Material and methods Forty-five monolithic zirconia specimens (16.3×16.4×2.0 mm) were divided into groups I to V, according to the number of colorings each received. Each group was then divided into 3 subgroups (n=3) according to the surface treatment: N=no treatment; P=polished; and G=glazed. CIElab color coordinates were obtained relative to D65 on a reflection spectrophotometer. The translucency parameter (TP) and opalescence parameter (OP) were calculated. One specimen per subgroups I and V was selected for evaluation of surface roughness (Ra) and was examined with scanning electron microscopy (SEM). Data were analyzed with 2-way ANOVA and pairwise comparisons (α=.05). Statistical powers were verified to evaluate results (α=.05). Results The interaction effects of surface treatments combined with the number of colorings were significant for TP, OP, and Ra ( P .05), whereas glazing significantly decreased OP and Ra in most groups. SEM images demonstrated that surface treatments affected the surface texture of monolithic zirconia ceramics. Conclusions Surface treatments combined with coloring strongly affect the surface texture of dental monolithic zirconia ceramics.