The aim of this study was to determine whether orthodontically moved maxillary canines exposed to two different protocols and dosage of LLLT exhibited differences in amount and rate of orthodontic tooth movement.

Fifteen orthodontic patients, 12 females and 3males, with a mean age of 17.48 ± 2.95 years were included. They had a clinical indication for bilateral extraction of at least first maxillary premolars. Using a split mouth design, maxillary left and right sides were randomly divided into two groups. In group 1, LLLT was delivered at 10 points; 5 from buccal and 5 from palatal aspects with a total dose of 8 Joule (J) per session that distributed as follows; 2 cervical, 1 middle, 2 apical. In group II, laser was applied from buccal side only at 5 points through the same order with a dose of 4 J per session. In both protocols, maxillary canines were irradiated with a gallium aluminum-arsenide diode laser in continuous mode with 635 nm, 100 mW, 25 J/cm2, 8 seconds/ point, 0.8 J/point. Both sides were distalized by a standard protocol with uniform 150 gm retraction force via a nickel-titanium closed coil spring. In both protocols, laser regimen was applied on days 0, 3, 7, and 14 in the 1st month, and thereafter on every 15th day until 6-month observation period of canine retraction phase. Amount and monthly rate of maxillary canine retraction and degree of anchorage loss were determined by direct intraoral and indirect 3D digital models measurements. Evaluations were undertaken immediately before initiating retraction (T0), after 4 weeks (T1), after 8 weeks (T2), after 12 weeks (T3), after 16 weeks (T4), after 20 weeks (T5), and after 24 weeks (T6). Significance level was set at p < 0.05.

Inclusion Criteria:

• Complete permanent dentition (3rd molars excluded).
• The age was ranged from 15 -25 years.
• Malocclusion that required extraction of at least maxillary first premolars, followed by canine retraction.
• Good oral hygiene and periodontal health.

Exclusion Criteria:

• Patients who diagnosed to have an indication for non-extraction approach.
• Serious systemic diseases and/or long term medications that could interfere with OTM.
• Previous orthodontic treatment.
• Poor oral hygiene or periodontally compromised patients.
• Craniofacial anomalies or history of parafunctional habits.