Corrosion Mechanism of a Dental Glass-Ceramic in Artificial Saliva and Sol-Gel Derived Corrosion-Resistant Coatings
齿科微晶玻璃的腐蚀机理及溶胶-凝胶防腐蚀涂层研究

The corrosion mechanism of a dental glass-ceramic: fluorcanasite by oral fluid and the corrosion-resistant ability of different sol-gel derived coatings on the glass-ceramic were investigated in vitro using SEM/EDAX, ICP and FTIR techniques. The results obtained show that the corrosion of the glass-ceramic by the oral fluid comes of a rapid ion exchange between HsO+ in the solution and Na+ (K+) in the surface layer of the glass-ceramic, which results in a loose Si02-rich layer on the glass-ceramic. Part of SiO2 component dissolves into the solution in the form of Si(OH)4 because Si-O-Si network of SiO2-rich layer is broken by attack of H2O. A lot of surface defects are formed on the surface due to the corrosion of water, which decrease the strength and service life of the glass-ceramic in an oral environment. The final reaction product on surface of the glass-ceramic is hydroxyl-carbonate apatite (HCA). Sol-gel derived Al2O3 coating has a significant ability to enhance the chemical durability of the dental glass-ceramic.