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

ObjectivesTo 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.MethodsOne hundred fifty ceramic discs of In-Ceram Spinell, In-Ceram Alumina and In-Ceram 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 1000× 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 °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.ResultsAll 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.ConclusionsSandblasting is an effective surface treatment for roughening surfaces of In-Ceram Spinell. Although CO2 laser irradiation does not increase surface roughness, it reveals the highest bond strength.