Photobiomodulation by a 635nm Diode Laser on Peri-Implant Bone: Primary and Secondary Stability and Bone Density Analysis—A Randomized Clinical Trial

Table 5

Mean grayscale values of 2 groups at apical level.

Period	Laser	Std	Control	Std	t-value	df	p-value
Baseline	1082.33	133.03	930.58	35.68	3.82	22	0.0009
4 weeks	465.83	34.80	700.33	47.34	-13.83	22	0.0000
12 weeks	708.08	121.43	439.50	27.06	7.48	22	0.0000

Std: standard deviation.
df: degree of freedom.