Table 3 Time-dependent changes in plaque index scores of teeth restored with crowns and intergroup comparisons between SSC and ZC

Month

Plaque index scores

Median (Q1, Q3)

Plaque index scores

Median (Q1, Q3)

p**

Baseline

1.5(1.25–1.75)

1.5(1.25–1.75)

0.362

1st month

1.5(1.0-1.75)

0.38(0-0.63)

< 0.001

6th month

1.5(1.25–1.75)

0.25(0-0.50)

< 0.001

12th month

1.5(1.25–1.75)

0(0–0)

< 0.001

18th month

1.625(1.25–1.75)

0(0–0)

< 0.001

p*

0.447

< 0.001