Table 4.

Mean grayscale values of 2 groups at middle level.

Period	Laser	Std	Control	Std	t-value	df	p-value
Basaline	1209.25	61.37	828.42	26.88	19.69	22	0.0000
4 weeks	573.42	20.96	551.17	34.35	1.92	22	0.0685
12 weeks	925.25	39.87	650.75	29.88	19.09	22	0.0000

Std: standard deviation.

df: degree of freedom.