Effect of surface treatment of a glass-infiltrated alumina ceramic on the microtensile bond strength

This study evaluated the microtensile bond strength of a resin composite to a ceramic submitted to three surface treatments. Twelve glass-infiltrated alumina ceramic blocks (In-Ceram Alumina, VITA) and twelve resin composite blocks (Clearfil APX, Kuraray) with dimensions of 6mm x 6mm x 5mm were made. The surface of the ceramic was wet-grounded with # 600, 800 and 1200-grid sandpaper, and the blocks were divided in three groups: Group 1 - sandblasting with aluminum oxide - particles 110mm (Micro-Etcher, Danville); Group 2 - Rocatec System (ESPE): Tribochemical silica coating (Rocatec pre-powder + Rocatec-Plus powder + Rocatec-Sil); Group 3 - CoJet System (3M/ESPE): silica coating (silica oxide + ESPE-Sil). The ceramic blocks were cemented to the resin composite blocks with Panavia F (Kuraray Co), following the manufacturer's instructions, under load of 750g for 10min. The samples were stored (distilled water / 7 days / 37O C) and sectioned in two axis, x and y, with diamond disk under cooling in order to obtain samples (S) with 0.6 ± 0.1mm2 of adhesive area (n=36). The S were attached in adapted device for the microtensile test that was performed at an universal testing machine (EMIC), at a speed of 1mm/min. The results (MPa) were submitted to ANOVA and Tukey's test (p<0.05): G1 - 15.36; G2 - 30.98; G3 - 31.25. Groups 2 (Rocatec) and 3 (CoJet) presented larger bond strength than group 1. There was no statistical difference between group 2 and group 3.