Clinical and radiographic performance of preformed zirconia crowns and stainless-steel crowns in permanent first molars: 18-month results of a prospective, randomized trial

Table 4 Time-dependent changes in gingival index scores of teeth restored with crowns and intergroup comparisons between SSC and ZC.

	Stainless Steel Crown	Zirconia Crown
Month	Gingival index scores Median (Q1, Q3)	Gingival index scores Median (Q1, Q3)	p***
Baseline	1.125(0.88–1.50)	1.25(1.0-1.38)	0.948^a
1st month	1.5(1.0-1.75)	1.0(0.75–1.75)	0.100^b
6th month	1.5(1.25–1.75)	0.125(1.0-1.50)	0.006 ^a
12th month	1.375(1.25–1.75)	0.875(0.50–1.25)	< 0.001 ^b
18th month	1.25(0.88–1.50)	0.5(0.25-1.0)	< 0.001 ^a
p	0.014*	< 0.001**

* Stainless steel crown repeated gingival index scores were compared using Friedman test
**Zirconia crown repeated gingival index scores were compared using one way analysis of variance for repeated measures due to the assumption of normality was satisfied
*** Gingival index scores of crowns were compared using Mann-Whitney U test: ^a p values were obtained using Student t test, ^b: p values were obtained using Mann-Whitney U test

ISSN: 1472-6831