Group A1 Control group

Group A2

(1.5% ZrO₂(

Group A3

(3% ZrO₂(

Group A4

(5% ZrO₂(

Group A5

(7% ZrO₂(

P-value

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Mean

SD

85.54^e

1.145

95.18^d

4.46

105.24^c

3.63

116.04^b

3.028

123.72^a

1.96

0.000^*