Several methods aiming at the acceleration of orthodontic tooth movement have been proposed, including low-level laser therapy (LLLT), which showed promising results. However, the frequency of patient recall has been one of its major drawbacks.

A randomized controlled clinical trial will be conducted to address the aim of the study. Sixteen patients will be recruited, requiring the therapeutic extraction of the maxillary 1st premolars, with subsequent canine retraction into the extraction space. The sample will be randomly divided into 2 equal groups, each including 8 subjects.

In Group A, one side of the maxillary arch will randomly receive LLLT on days 0, 3, 7, 14, and every 2 weeks thereafter, while in Group B, one side will also be randomly chosen to receive LLLT every 3 weeks. The contralateral sides of both groups will serve as the controls. The LLLT applied will be Diode laser emitting infrared radiation at wavelength of 980 nm, in a continuous mode.

Canine retraction in both groups will be carried out bilaterally using nickel-titanium closed-coil spring, delivering 150 grams of force, and the rate of tooth movement will be checked every 3 weeks, over a period of 3 months. Other variables will be also examined including, interleukin-1β level in the gingival crevicular fluid, root resorption, and molar anchorage loss.

Inclusion Criteria:

• Malocclusion requires at least the extraction of maxillary first premolars, followed by canine retraction into the extraction site.
• Normal shape and structure of the maxillary canines, with no history of root canal treatment.
• Patients with good oral hygiene, and a healthy periodontal condition.

Exclusion Criteria:

• Patients who underwent previous orthodontic treatment.
• Patients currently receiving drug therapy that may affect orthodontic tooth movement, e.g. hormonal therapy and corticosteroids.
• Patients with chronic diseases that may affect the rate of tooth movement.
• Pregnancy and lactation