Assessment of the bond strength between resin cement and lithium disilicate based glass ceramics with different chemical composition and surface treatments

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Bebsh, Muna Jr
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Objective: The purpose of this research project is to evaluate and compare the effect of different surface treatments on surface properties. Also the effect of different surface treatments with silane coupling agents on the bond strengths between resin cement and four CAD/CAM lithium disilicate-based glass ceramics (LDGC). Materials and methods: This study had three levels of analyses. Part I: The physicochemical analyses of four CAD/CAM LDGC surfaces. The surface physicochemical compositions of the four LDGC products (e.max CAD, Vita Suprinity, Celtra Duo, n!ce) were analyzed using X-ray photoelectron spectroscopy (XPS). In addition, scanning electron microscopy (SEM) was used to analyze the microstructure of LDGC. Part II: The effect of different surface treatments on the micromorphology and the roughness of four CAD/CAM lithium disilicate- based glass ceramics Atomic force microscopy (AFM) was used to measure the surface roughness and scanning electron microscopy (SEM) was used to analyze the changes in the surface micromorphology. Part III: The effect of an experimental silane coupling agent (TEOS) with different surface treatments on bond strength of four CAD /CAM lithium disilicate-based glass-ceramics. The shear bond strength between the ceramic surface and resin cement was tested using shear bond testing after a 30 day storage in distilled water. Results: The chemical composition percentage on the nano surfaces of the LGGC changed after hydrofluoric acid treatment. Different surface treatments produced different values of roughness. The highest shear bond strength values were found with the use of hydrofluoric acid treatment and the combination of both hydrofluoric acid and sandblasting followed by manufacturer’s recommendation of silane coupling application. Conclusion: Surface treatments and silane coupling agents play a significant role to obtain reliable bond strengths between resin cement and LDGC restorations.
Lithium disilicate-based glass ceramic, Surface treatments, Bond strength