PURPOSE: To evaluate the polishing effect on roughness and color change of pressed and layering ceramics after immersion in coffee solution.
Ceramics ; Coffee ; Diamond ; Immersion ; Lithium ; Microscopy, Electron, Scanning ; Pigmentation ; Spectrophotometry

PURPOSE: The aim of this study is to evaluate the influence of repeated surface treatments on wettability and surface roughness for zirconia surface and bond strength of zirconia-based ceramics to resin cement. MATERIALS AND METHODS: Seventy blocks (10 × 10 × 3 mm) of zirconia-based ceramics were fabricated and divided into two groups according to the surface treatments: (A) 110 μm Al2O3 airborne-particle abrasion and (R) 110 μm silica modified Al2O3 airborne-particle abrasion. At stage 2, each group was subdivided into 5 groups according to the surface retreatments: (a) 110 μm AlO3 airborne-particle abrasion, (r) 110 μm silica modified Al2O3 airborne-particle abrasion, (D) diamond bur, (Da) diamond bur + 110 μm Al2O3 airborne-particle abrasion, and (Dr) diamond bur + 110 μm silica modified Al2O3 airborne-particle abrasion. Cylinders of self-adhesive resin cement were cemented onto each treated ceramic surface and subjected to micro-shear bond strength test.Additional specimens were prepared for roughness and wettability analyses. The data were subjected to t-test and One-way ANOVA followed by Tukey’s post hoc test (α=.05). RESULTS: At stage 1, group R presented higher bond strength values than group A (P=.000). There was a statistically significant increase of bond strength at stage 2 for group A (P=.003). The diamond bur influenced the surface roughness, increasing the values (P=.023).Group R provided better wettability. Regardless of the applied surface treatment, most of failures were adhesive. CONCLUSION The combination of application and reapplication of Rocatec Plus showed the best results of bond strength. Surface retreatment and recementation might be an indicated clinical strategy.