Table 5.

Means and standard deviation values for surface roughness for all subgroups of the two composites in shade A4.

Variable	Material	Bleach	Mean	SD	Regression analysis for materials	Regression analysis for bleach agents
After first bleach	Durafil VS	Control	106.7	2.1	<0.001*	0.039*
		Beyond	107.2	2.4
		Luma	109.2	2.1
		Opal	114.3	2
	TPH3	Control	100.5	5.3
		Beyond	102.6	8.1
		Luma	100.2	4.9
		Opal	106.1	5.9
After second bleach	Durafil VS	Control	106.7	2.1	<0.001*	<0.001*

^*:Significant at P≤.05