Effect of Multiple Firing on Wear Behavior of Dental Veneering Ceramic

This study investigated the effect of multiple firing on the wear behavior of dental all-ceramic veneering ceramic (Cercon). Samples were fabricated according to the manufacturer's requirement for different firing times. The wear test was operated under simulated oral environment. The results showed that multiple firing could influence wear behavior of all-ceramic Veneer. Significant difference was observed in wear scar width among different samples. All the groups except 7time-firing one showed good wear resistance with low wear rate, smooth surface and relatively constant frictional coefficient. With the increasing firing times the wear scar width became larger. The wear resistance of dental ceramic after seven times firing was significantly lower. SEM/DFM results showed the wear facets of veneering ceramic demonstrate grooves characteristic of abrasive wear. The significant change was that severe wear dominated by brittle fracture could be seen in the 7time-firing group. Multiple firing can decrease the wear resistance of dental all-ceramic Veneer, and the wear pattern has the tendency to severe wear. The possible explanation is that the microstructure and properties of all-ceramic Veneering changed during multiple firing.