Two Low-level Laser Irradiation Protocols on the Rate of Canine Retraction

The Effect of Two Low-level Laser Irradiation Protocols on the Rate of Canine Retraction (a Randomized Controlled Clinical Trial)

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.

one side of the maxillary arch will randomly receive LLLT on days 0, 3, 7, 14, and every 2 weeks thereafter and the contralateral side will serve as the controls.

one side will also be randomly chosen to receive LLLT every 3 weeks and the contralateral side will serve as the controls.

Several landmarks will be identified on the dental cast, including the mid-palatal raphe, the most medial points on the third right and left rugae, and the cusp tips of the right and left maxillary canines. Perpendicular lines will be drawn from the medial points of the right and left third rugae, and the cusp tips of the right and left maxillary canines to the mid-palatal raphe. The antero-posterior measurements will be carried out between the canine lines and the third rugae lines bilaterally, to assess the rate of canine retraction.

Samples from the GCF will be collected at baseline (before the first canine retraction), in addition to days 7, 14, and 21. GCF samples will be collected from the distal crevices of the canines, in Groups A and B, on both the experimental and control sides. Measurement of IL-1β level in the GCF will be performed using an ELISA kit.

Root resorption of the maxillary canines will be evaluated and measured on the acquired pre-retraction and post-retraction CBCT scans.

Perpendicular lines will be drawn from the central fossae of both maxillary right and left first molars to the mid-palatal raphe. Consequently, molar anchorage loss will be calculated by measuring the distance between those lines, and the lines representing the third rugae as previously mentioned.

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

Eid FY, El-Kenany WA, Mowafy MI, El-Kalza AR. The influence of two photobiomodulation protocols on orthodontically induced inflammatory root resorption (a randomized controlled clinical trial). BMC Oral Health. 2022 Jun 5;22(1):221. doi: 10.1186/s12903-022-02251-w.