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Lee A, Swain M et al. J Prosthet Dent 2014; 112: 1399–1405

These investigators used SEM to identify wear scars on flat enamel specimens. The enamel was subjected to wear, by spherical-ended cylinders of heat pressable lithium disilicate glass ceramics (IPS e.max Press, Ivoclar Vivadent AG) and type III polished gold. A horizontal wear testing apparatus was used that generated an amplitude of 200 μm. The specimens were subjected for up to 1,100 cycles and loaded to 9.8 N. Distilled water was used as a lubricant. The testing apparatus also incorporated a calibrated load cell to measure frictional forces. Despite methodological limitations, it was reported that IPS e.max Press resulted in more wear to the enamel has a higher friction coefficient than gold. Abrasive wear would appear to be the predominant wear mechanisms for IPS e.max Press. For gold, transfer of this malleable metal from the cylinder to the antagonist would imply adhesive wear. The surfaces tested were those as supplied from a laboratory; glazed ceramic and polished gold.