The friction and wear behaviors of dental porcelains with different surface strengthening techniques

The friction and wear behavior of dental feldspathic ceramics, treated distinctively by three routine surface strengthening techniques (auto-glazing, ion exchange and polishing), were investigated by cyclic sliding against pure titanium ball on a modified fretting friction and wear test rig under imitating oral enviorment. The wear scars of the samples were characterized with 3-D con focused laser-scanning microscope. The wear depths were analyzed statistically and the element concentrations of Ti, Al and Si on the scar before and after surface treatments were determined with energy dispersion spectrometry. The correlations between the wear behaviors and micro hardness or toughness were also compared. The results show the present routine surface strengthening methods have little effects on the friction coefficient of dental porcelain, but play an role in improving the wear behavior of ceramics at the early stage of sliding cycles. The effect of surface ion exchange is better than that of auto-glazing or polishing. The friction and wear behavior of dental ceramics depend on the material itself especially after the surface-strengthening layer disappeared. Abrasive wear, adhesion and micro cracking characterize the wear mechanism of dental feldspathic ceramics after the surface-strengthening treatments.