Table 7.

Tooth wear evaluation

Chi-square test		Zirconia crowns	Strip crowns	p-value
Tooth wear of opposing
At 3 months	No loss of enamel surface characteristics, no loss of contour	60 (100.0%)	60 (100.0%)	N/Ac
At 6 months	No loss of enamel surface characteristics, no loss of contour	60 (100.0%)	60 (100.0%)	N/Ac
At 12 months	No loss of enamel surface characteristics, no loss of contour	53 (88.3%)	60 (100.0%)	0.020a
	Loss of enamel surface characteristics, minimal loss of contour	7 (11.7%)	0 (0.0%)

Friedman test	Mean rank
	Total cases	Zirconia crown	Strip crown
Baseline	2.47	2.44	2.50
At 3 months	2.47	2.44	2.50
At 6 months	2.47	2.44	2.50
At 12 moths	2.59	2.68	2.50
p-value	< 0.001b	< 0.001b	N/Ac

^aSignificant using Chi-Square Test @ < 0.05 level

^bSignificant using Friedman Test @ < 0.05 level

^cNo statistics are computed because variable is a constant