Effect of water glass treatment for zirconia and silane coupling on bond strength of resin cement

• Published in: Clinical oral investigations Vol. 28; no. 6; p. 305
• Main Authors: Ushijima, Kei, Hiraishi, Noriko, Ikeda, Masaomi, Tsuji, Yukiko, Tsuchida, Yumi, Shimada, Yasushi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 09-05-2024; Springer Nature B.V
• Subjects: Biomedical materials; Bond strength; Cement; Dental Bonding - methods; Dental implants; Dental restorative materials; Dental Stress Analysis; Dentistry; Electron probe; Glass - chemistry; Materials Testing; Medicine; Microscopy, Electron, Scanning; Resin Cements - chemistry; Resins; Silanes - chemistry; Surface Properties; Tensile Strength; Thermal cycling; Water - chemistry; Zirconia; Zirconium - chemistry; Zirconia; Resin cement; Bond strength; Silane coupling; Water glass
• DOI: 10.1007/s00784-024-05680-9
• EISSN: 1436-3771
• ISSN: 1436-3771; 1432-6981

Objective
To evaluate the ability of the water glass treatment to penetrate zirconia and improve the bond strength of resin cement.
Material and methods
Water glass was applied to zirconia specimens, which were then sintered. The specimens were divided into water–glass-treated and untreated zirconia (control) groups. The surface properties of the water–glass-treated specimens were evaluated using surface roughness and electron probe micro-analyser (EPMA) analysis. A resin cement was used to evaluate the tensile bond strength, with
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and without a silane-containing primer. After 24 h in water storage at 37 °C and thermal cycling, the bond strengths were statistically evaluated with t-test, and the fracture surfaces were observed using SEM.
Results
The water glass treatment slightly increased the surface roughness of the zirconia specimens, and the EPMA analysis detected the water glass penetration to be 50 μm below the zirconia surface. The application of primer improved the tensile bond strength in all groups. After 24 h, the water–glass-treated zirconia exhibited a tensile strength of 24.8 ± 5.5 MPa, which was significantly higher than that of the control zirconia (17.6 ± 3.5 MPa) (p < 0.05). After thermal cycling, the water–glass-treated zirconia showed significantly higher tensile strength than the control zirconia. The fracture surface morphology was mainly an adhesive pattern, whereas resin cement residue was occasionally detected on the water–glass-treated zirconia surfaces.
Conclusion
The water glass treatment resulted in the formation of a stable silica phase on the zirconia surface. This process enabled silane coupling to the zirconia and improved the adhesion of the resin cement.