Long-term Adhesive Performance to Glass-ceramics of a Self-priming Etchant

Objectives: Evaluating the long-term performance of a self-priming ceramic etchant (Monobond Etch, MBEP) on micro-tensile bond strength (MTBS) to leucite reinforced (IPS Empress CAD) and lithium-disilicate reinforced (IPS e.max CAD) glass-ceramic CAD/CAM blocks.
Methods: Six mm thick CAD/CAM blocks received following surface treatments: IPS Empress CAD groups: 1. no HF acid, no silane; 2. 60 s HF acid, no silane; 3. 60 s HF acid, silane; 4. MBEP applied for 20 s and left for 40 s; 5. MBEP applied for 20 s and left for 100 s. IPS e.max CAD groups: 6. 20 s HF, silane; 7. MBEP applied for 20 s and left for 40 s. Sandblasted composite blocks (Lava Ultimate) were cemented with dual-cure resin cement (RelyX Ultimate). Half of the specimens were processes for MTBS testing after 72 hours of water storage, the other half after 6 months water storage. MTBS was performed using a universal testing machine (Instron) at crosshead speed of 0.5 mm/min. For statistical analysis a 2 way ANOVA (surface treatment and age) with Games-Howell post-hoc test was performed at α=0.05.
Results: Mean MTBS values in MPa and (Pre-testing failure/Number of sticks) are displayed in Table 1
Conclusions: Long-term bond strength to leucite reinforced glass ceramic using a self-etching primer is comparable to using HF acid and silane. The used bonding protocols to lithium-disilicate reinforced glass-ceramic did not result in stabile long-term bond. Therefore, this study shows that long-term efficacy of self-priming ceramic enchant is highly depend on the ceramics' composition and structural arrangement.