Eleven patients were recruited for this 2-month study. One half of the upper arcade was considered control group (CG) and received mechanical activation of the canine teeth every 30 days. The opposite half received the same mechanical activation and was also irradiated with a diode laser emitting light at 780 nm, during 10 seconds at 20 mW, 5 J/cm², on 4 days of each month. Data of the biometrical progress of both groups were statistically compared. All patients showed significant higher acceleration of the retraction of canines on the side treated with LLLT when compared to the control. These findings suggest that LLLT does accelerate human teeth movement and could therefore considerably shorten the whole treatment duration.