Luting cements containing phosphate-monomer (MDP) have been suggested to achieve a reliable chemical bond to zirconia (Y-TZP). Otherwise Y-TZP surface has to be conditioned one way or another. Objectives: Aim of the study was to compare various combinations of silicatization and silanization to improve bonding of a non-MDP luting cement (RelyX Unicem, 3M-ESPE) toY-TZP (Zirkon Keramik Ice, Zirkonzahn GmbH). Shear-bond-strength was measured and compared to a control group E with an alternative luting cement (Multilink Sprint, Ivoclar-Vivodent). Methods: Sintered Y-TZP substrates were first air-borne particle abraded (Al2O3, 50μm) using air-pressure of 450kPa for 10s. The surfaces were treated as shown in table below. Composite-luting cement stubs (diameter 3.6mm, height 4.0mm) were added to substrates and photopolymerized for 40s (Optilux-501, Kerr, USA). The specimens (n=15/gp) were thermocycled (6000x55º-5ºC). The shear-bond-strength of the luting cement to Y-TZP was measured with a crosshead speed of 1.0mm/min. Failure fracture surfaces were examined with SEM. Results: Mean values of shear-bond-strength (SBS) are shown in table below:
|
|
Silicatization method |
Silanization |
Luting cement |
SBS (MPa) |
|
Group A |
Silano-Pen (Bredent), duration 10s |
- |
RelyX Unicem (3M-ESPE) |
5.9±3.1 |
|
Group B |
Silano-Pen (Bredent), duration 10s |
ESPESil (3M-ESPE)
|
RelyX Unicem (3M-ESPE) |
11.1±2.3 |
|
Group C |
Silano-Pen (Bredent ), duration 10s CoJet (3M-ESPE), duration 10s |
ESPESil (3M-ESPE) |
RelyX Unicem (3M-ESPE) |
12.4±2.0 |
|
Group D |
- |
ESPESil (3M-ESPE) |
RelyX Unicem (3M-ESPE) |
6.6±3.2 |
|
Group E |
- |
- |
Multilink Sprint (Ivoclar-Vivodent) |
12.5±4.2 |
Statistical analysis (ANOVA) showed significant difference between groups (p<0.05).
Conclusion: There were considerable differences between the bond strengths achieved by various surface treatment methods.