Table 5. Mean volumetric wear amounts of the ceramic material groups and opposing enamel for 0 – 6 months.

Ceramic group	Material		Mean wear (mm3)	SD	Number of crowns
Glass matrix	Restoration	EM	0.272057	0.1589849	7
		VS	0.142325	0.1412636	5
					Total: 12
	Enamel	EM	0.260643	0.1657518	7
		VS	0.276100	0.1366608	5
					Total: 12
Resin matrix	Restoration	GC	0.451217	0.1894061	7
		VE	0.389580	0.1653977	5
					Total: 12
	Enamel	GC	0.339150	0.1876026	7
		VE	0.396080	0.1728979	5
					Total: 12
Total					24