Long-Term Resin Bond Strength to Procera Ceramic

Objectives: The purpose of this in-vitro study was to evaluate the bond strength of various adhesive bonding systems to Procera ceramic. Methods: Plexiglas tubes (inner diameter 3.3 mm) filled with resin Clearfil F2 (Kuraray, J) were bonded to industrial manufactured Procera discs (99.9% Al2O3 Nobel Biocare, S). The discs had a diameter of 7.4 mm and a thickness of 3.4 mm. Eight groups of 20 samples each were bonded in an alignment apparatus using the following procedures: (SV) sandblasted (Al2O3), Variolink II (Vivadent, FL); (SRV) Rocatec-System (Espe, FRG), Variolink II; (UAV) untreated, Alloy Primer (Kuraray), Variolink II; (SAV) sandblasted, Alloy Primer, Variolink II; (USB) untreated, Superbond C&B (Sun Medical, J); (SSB) sandblasted, Superbond C&B; (UP) untreated, Panavia 21 (Kuraray); (SP) sandblasted, Panavia 21. Subgroups of 10 bonded samples were stored for 3 days (A) or 150 days intermitted by 37.500 thermocycles between 5°C and 55°C (B). Results: The mean tensile bond strengths (TBS) in MPa were: (SV/A) 18.2 ± 3.0; (SV/B) 0.0 ± 0.0; (SRV/A) 33.3 ± 2.6; (SRV/B) 25.4 ± 5.5; (UAV/A) 9.7 ± 3.0; (UAV/B) 0.0 ± 0.0; (SAV/A) 32.5 ± 3.4; (SAV/B) 30.3 ± 4.5; (USB/A) 5.6 ± 7.6; (USB/B) 0.0 ± 0.0; (SSB/A) 32.1 ± 5.3; (SSB/B) 16.4 ± 4.5; (UP/A) 3.9 ± 5.4; (UP/B) 0.0 ± 0.0; (SP/A) 45.1 ± 1.0; (SP/B) 37.1 ± 6.2. There were statistically significant differences (SSD) among groups as revealed by the Kruskal-Wallis-test (p<0.001) and Wilcoxon rank sum test modified by Bonferroni-Holm. All untreated bonding groups (U) showed SSD lower tensile bond strength values compared to groups with initial ceramic surface treatment (S). Conclusions: The results show that groups SAV and SP were the only groups revealing a durable resin bond to Procera ceramic.