Sliding Wear Behavior of a Lithium Disilicate Glass-ceramic for Dentistry

Sliding wear behavior of a lithium disilicate glass-ceramic for dentistry was investigated using a pin-on-disk wear tester under the lubricating condition with artificial saliva. It is found that severe running-in wear exhibited because, the wear rate in the running-in region was much higher than that in the steady wear region. Decreasing the initial surface roughness of the wear surface shortened the running-in period and reduced the corresponding wear rate. Although the lithium disilicate crystalline phase in the microstructure of the glass-ceramic has higher hardness than the glass matrix, the crystalline phase was prone to spall predominantly in the running-in process, resulting in remarkable change of the worn surface roughness. The phenomenon was correlated with the lower elastic strain to failure (H/E ratio) of lithium disilicate crystalline phase.