IADR Abstract Archives
CAD/CAM Blocks Microstructural Impact on Microtensile Bond Strength
Objectives: To evaluate the adhesive bonding performance of 2 leucite-reinforced glass ceramic CAD/CAM materials after different surface treatment protocols.
Methods: The CAD/CAM materials under investigation were: InitialTM LRF (IR) (GC Europe, Leuven, Belgium) and IPS Empress® CAD (EM) (Ivoclar Vivadent, Schaan, Liechtenstein). The blocks received various surface treatments (no treatment, silane only, sandblasting + silane, hydrofluoric acid + silane), 2 types of adhesive luting composites were applied (G-CEM LinkForce; GC Europe, Leuven, Belgium) with the corresponding Silane (G-Multi Primer) or (Multilink® Automix; Ivoclar Vivadent, Schaan, Liechtenstein) with the corresponding Silane (Monobond Plus). After water storage and 5,000 thermocycles (5°C/55°C), specimens were cut into beams and microtensile bond strengths were recorded. The samples were observed by Scanning Electron Microscopy to correlate the impact of the surface treatment on the block material. The type of fracture resulting for each group was observed under stereo microscope and classified under 3 categories (adhesive, cohesive or mixed).
Results: Bonding performance of CAD/CAM materials was clearly influenced by the pretreatment method (P < 0.05). In general, all materials showed sufficient bonding to withstand intraoral chewing forces during mastication. Higher μ-TBS values were recorded for the InitialTM LRF blocks (IR) when treated with hydrofluoric acid (P < 0.05), irrespective of the adhesive luting composites (G-CEM LinkForce and Multilink® Automix). Fracture analysis of tested specimens revealed a correlation between type of fracture and microstructure of the CAD/CAM blocks.
Conclusions: Surface roughening methods and an appropriate primer are required to promote adequate and effective adhesion to CAD/CAM ceramic blocks. Structural differences observed in SEM and fracture analysis, combined to the effect of surface treatments on different materials, may impact the quality and longevity of the adhesive interface. InitialTM LRF blocks treated with hydrofluoric acid and silane seem to offer the best combination in terms of bonding effectiveness.
Methods: The CAD/CAM materials under investigation were: InitialTM LRF (IR) (GC Europe, Leuven, Belgium) and IPS Empress® CAD (EM) (Ivoclar Vivadent, Schaan, Liechtenstein). The blocks received various surface treatments (no treatment, silane only, sandblasting + silane, hydrofluoric acid + silane), 2 types of adhesive luting composites were applied (G-CEM LinkForce; GC Europe, Leuven, Belgium) with the corresponding Silane (G-Multi Primer) or (Multilink® Automix; Ivoclar Vivadent, Schaan, Liechtenstein) with the corresponding Silane (Monobond Plus). After water storage and 5,000 thermocycles (5°C/55°C), specimens were cut into beams and microtensile bond strengths were recorded. The samples were observed by Scanning Electron Microscopy to correlate the impact of the surface treatment on the block material. The type of fracture resulting for each group was observed under stereo microscope and classified under 3 categories (adhesive, cohesive or mixed).
Results: Bonding performance of CAD/CAM materials was clearly influenced by the pretreatment method (P < 0.05). In general, all materials showed sufficient bonding to withstand intraoral chewing forces during mastication. Higher μ-TBS values were recorded for the InitialTM LRF blocks (IR) when treated with hydrofluoric acid (P < 0.05), irrespective of the adhesive luting composites (G-CEM LinkForce and Multilink® Automix). Fracture analysis of tested specimens revealed a correlation between type of fracture and microstructure of the CAD/CAM blocks.
Conclusions: Surface roughening methods and an appropriate primer are required to promote adequate and effective adhesion to CAD/CAM ceramic blocks. Structural differences observed in SEM and fracture analysis, combined to the effect of surface treatments on different materials, may impact the quality and longevity of the adhesive interface. InitialTM LRF blocks treated with hydrofluoric acid and silane seem to offer the best combination in terms of bonding effectiveness.