Shearbond Strength of Cements to Zirconia and Lithium Disilicate Ceramics

Objectives: This study determined the shearbond strength of cements to different ceramics: zirconia (LAVA, 3M ESPE) and lithium disilicate (Empress 2, IvoclarVivadent). Methods: Zirconia samples were 100 microns Al2O3 abraded at 2.8 bar, 10s at 10 mm distance. Lithium disilicate samples were HF- etched and silanated. Materials tested: 1) Fleck’s (Mizzy), 2) Fuji I (GC), 3) Ketac-Cem Aplicap (3M ESPE), 4) Fuji Plus (GC), 5) Fuji Cem (GC), 6) RelyXLuting (3M ESPE), 7a) RelyXARC (3M ESPE), 7b) RelyXARC light-cured (LC), 8a) Panavia F (Kuraray), 8b) Panavia F LC, 9a) Variolink (IvoclarVivadent), 9b) Variolink LC, 10a) Compolute Aplicap (3M ESPE), 10b) Compolute LC,11a) Experimental resin based cement (3M ESPE) and 11b) Experimental resin based LC cement. Ten specimens per group were fabricated: Group (A) tested at 30 minutes; (B) 14day 37C water storage, then thermocycled (1.000X, 5-55C). ANOVA was used to analyze data (p<.05). Results: Significantly higher shearbond strength to zirconia were found at 30 minutes for cements 4, 7b, 8b, 9b, 10b, 11b compared to the other materials. After (B) treatment cements 1, 2, 3, 6, 10a and 10b failed before testing. 11a and 11 b reached with 7.1 +/- 2.1 MPa and 12.7 +/- 2.3 MPa, the highest measured values after (B) treatment. For lithium disilicate, all cements achieved high bond strength at 14d after thermocycled except cements 1, 2 and 3. The highest value after (B) treatment was 9b with value of 18.8 +/- 5.9 MPa. 11b, 9a and 11a followed with results of 18.4 +/- 2.2 MPa, 15.6 +/- 4.2 MPa and 15.1 +/- 2.1 MPa respectively. Conclusions: Bonding to zirconia of cement 11a and 11b was significant higher compared to all other materials after treatments (A) and (B). Most stable bonding to lithium disilicate was achieved with cements 7b, 9a, 9b, 10a, 10b, 11a and 11b.