Bleaching agents

Mean

S.D.

Min.

Max.

dt

 

 

Control group (no bleaching)

 

 

121.56

 

 

30.39

 

 

71.34

 

 

234.33

 

 

b

Opalescence 20% CP

172.31

19.32

114.08

297.12

a

Opalescence10% CP

160.54

33.72

90.5

291.34

a

Zoom 25% HP

154.86

32.9

95.29

288.13

a
S.D.=Standard deviation; dt = Duncan’s Multiple Range Test. Means with the same letter within each column are not significantly different at p≤0.05
Table (1): Descriptive statistics and test of significance for surface roughness of the tested bleaching agents.