Effect of different surface treatments on optical, colorimetric, and surface characteristics of a lithium disilicate glass–ceramic

Abstract

Objective: To evaluate the effect of surface treatments on optical, colorimetric, and surface characteristics of lithium disilicate glass-ceramic.Materials and Methods: Specimens (n = 5, IPS e.max CAD) were randomly allocated to the following treatments: mirror-polished: SiC papers; as-cut: mimicking CAD-CAM milling; ground: 90-120 μm-grit diamond bur; ground polished: ground, finished (46-30 μm-grit diamond bur), polished (diamond cups, brush and diamond paste); ground glazed: ground, glazed; ground polished glazed: association of methods. CIELAB color coordinates were obtained by a spectrophotometer. CIEDE2000 color differences (ΔE 00 ) and the translucency parameter (TP 00 ) were calculated. Light transmittance was assessed with a colorimeter. Surface characteristics (topography and roughness) were analyzed. Statistical differences for each condition and outcome were detected using one-way ANOVA with Tukey's post-hoc test (α = 0.05).Results: TP 00 data show statistical reduction after grinding (p < 0.05), which was only restored with polishing (solely or with glazing). ΔE 00 shows that grinding results in perceptible variations in color (above 0.81), which were restored after all postprocessing protocols (exception to only glaze application in contact with a black background). Light transmittance data corroborated such performance. Polishing and glazing reduced roughness and improved surface topography. Conclusion:Grinding statistically increased roughness, reduced translucency, light transmittance through the ceramic, and resulted on color differences. On contrary, polishing (followed or not by glazing) reduced roughness and enhanced ceramic translucency and light transmittance. Glaze also reduced roughness, but it still presented reduced translucency. The positioning (facing up or down) of the ceramic treated surface influenced the considered outcomes.Clinical Significance: Grinding with diamond burs results in a deleterious impact to the optical, colorimetric and surface characteristics of lithium disilicate ceramic. Thus, polishing (followed or not by glazing) is recommended for optical and topographical enhancements when lithium disilicate monolithic restorations require occlusal adjustments.

Colorimetric analysis of dental porcelains: effects of the background color

“…Previous studies have shown that even dental ceramics are prone to color alteration by staining [24][25][26]. However, the color difference can be calculated from other situations that restorative materials are subjected to, such as thermal [21,37] or surface treatments [38]. Even though our conclusions might be cautiously inferred for color difference analyses other than by staining, more studies on this topic (background effect) are encouraged.…”

Optical properties, biaxial flexural strength, and reliability of new‐generation lithium disilicate glass‐ceramics after thermal cycling

“…Weighting functions of S L , S C , and S H are used to adjust the total color difference. The parametric factors ( k L , k C , and k H ) were considered 1 3,18–20 …”

Indirect restorative systems—A narrative review

“…Surface finishing of glass ceramics usually consists of polishing and/or glazing. [79][80][81][82] After finishing, the surface becomes smoother, which might result in some clinical benefits, such improved esthetics of the restoration and decreased antagonist wear. 83 Both techniques, polishing and glazing, have been the focus of research comparing the surface properties and color stability of glass ceramics before and after different finishing procedures; however, there is not a consensus in the literature concerning the ideal protocol.…”

“…83 Both techniques, polishing and glazing, have been the focus of research comparing the surface properties and color stability of glass ceramics before and after different finishing procedures; however, there is not a consensus in the literature concerning the ideal protocol. Most of the studies have indicated that polished surfaces (depending on protocol) results in smoother surfaces than glazed surfaces [79][80][81][82] ; however, glazing might also have a potential improved effect on color stability and flexural strength of glass ceramics. 80 Besides finishing procedures, staining of ceramic restorations might be a useful procedure to improve the mimicking of nuances and shade of natural teeth, especially for monolithic restorations that usually do not meet the high esthetic demands without staining.…”

“…Surface finishing of glass ceramics usually consists of polishing and/or glazing 79–82 . After finishing, the surface becomes smoother, which might result in some clinical benefits, such improved esthetics of the restoration and decreased antagonist wear 83 .…”