Surface roughness and bond strengths of glass-infiltrated alumina-ceramics prepared using various surface treatments

Objectives: To compare and evaluate effects Of CO2 laser and conventional surface treatments on surface roughness and shear bond strengths of glass-infiltrated alumina-ceramics to dentin. Methods: One hundred fifty ceramic discs of In-Ceram Spinell, In-Ceram Alumina and InCeram Zirconia (n = 50) were prepared. Specimens which were divided into 5 groups (n = 10) were untreated (control group), sandblasted, airborne particle abraded, etched with 9.6% hydrofluoric acid or irradiated with CO2 laser. Scanning electron microscope was used at 1000x magnification for qualitative examination. Following surface roughness (Ra) determination by profilometry, discs were cemented on extracted-human-molar teeth. Cemented specimens were stored in distilled water at 37 degrees C for 1 week. Shear bond strength (MPa) test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Statistical comparisons were made with Wilcoxon signed ranked test, Kruskall Wallis test and Spearman's correlation coefficient. Results: All surface treatments produced rougher surfaces than the untreated groups of all ceramics (P < .05). Sandblasting demonstrated a rougher surface on In-Ceram Spinell than In-Ceram Alumina and In-Ceram Zirconia (P < .05). While CO2 laser irradiation showed significantly higher bond strength for in-Ceram Spinell (P < .05), both airborne particle abrasion and CO2 laser irradiation showed higher bond strengths for in-Ceram Zirconia (P < .05). Airborne particle abrasion demonstrated higher bond strength for In-Ceram Alumina and In-Ceram Zirconia (P < .05). No significant relationship was determined between surface roughness (Ra) and shear bond strength values (MPa) among ceramic groups. Conclusions: Sandblasting is an effective surface treatment for roughening surfaces of InCeram Spinell. Although CO2 laser irradiation does not increase surface roughness, it reveals the highest bond strength. (C) 2009 Elsevier Ltd. All rights reserved.