The objective of this study was to evaluate the canine retraction rate with two low-level laser therapy (LLLT) irradiation protocols, involving both a high and a low application frequency. Twenty patients were randomly divided into two equal groups. In Group A, one side of the maxillary arch randomly received LLLT on days 0, 3, 7, 14, and every 2 weeks thereafter, whereas in Group B, one side received LLLT every 3 weeks. Tooth movement was checked every three weeks since the onset of canine retraction, over the 12-week study period. Moreover, Interleukin-1β (IL-1β) levels in the gingival crevicular fluid were assessed. Results revealed a significant increase in the canine retraction rate on the laser sides of groups A and B, in comparison with the control sides (p < 0.05), with no significant differences reported between the laser sides in both groups (p = 0.08–0.55). Also, IL-1β levels were significantly higher on the laser sides of both groups, in comparison with the control sides (p < 0.05). Therefore, LLLT can effectively accelerate tooth movement, with both frequent and less frequent applications, which is attributed to an enhanced biological response as reflected by the elevated IL-1β levels on the compression sides.

Background Controversial results have been reported regarding the impact of photobiomodulation (PBM) on orthodontically induced inflammatory root resorption (OIIRR). The aim of this study was to evaluate the influence of two PBM protocols, one of them requiring a high application frequency (on days 0, 3, 7, 14, then every 2 weeks), while the second requires less frequent applications (every 3 weeks), on OIIRR accompanying orthodontic treatment. Methods Twenty female patients were recruited for this randomized controlled trial, requiring the therapeutic extraction of maxillary first premolars, and they were randomly divided into 2 equal groups. In Group A, one side of the maxillary arch randomly received PBM on days 0, 3, 7, 14, and every 2 weeks thereafter, while in Group B, one side was randomly chosen to receive PBM every 3 weeks. The laser applied was a Diode laser with a wavelength of 980 nm, in a continuous mode. Canine retraction in both groups was carried out using closed-coil springs, delivering 150 g of force, and the force level was checked every 3 weeks, over a 12-week study period. Pre-retraction and post-retraction cone-beam computed tomography (CBCT) was done for the evaluation of OIIRR. Results No significant differences in the amount of OIIRR have been reported between the laser and control sides in both groups A and B. Also, no significant differences have been reported between the laser sides in both groups. Conclusions Photobiomodulation does not affect OIIRR, whether by increasing or decreasing its occurrence, with both laser application protocols. Therefore, it can be stated that PBM does not result in root resorption less than the commonly observed range elicited with conventional orthodontic treatment, and that it has no effect on OIIRR. Trial registration Two Low-level Laser Irradiation Protocols on the Rate of Canine Retraction (NCT04926389), 15/06/2021—retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT04926389.

No abstract

Objective: Low-level laser therapy (LLLT) has been found to accelerate the rate of tooth movement, which in turn may aid in preserving posterior anchorage. However, one of the drawbacks of LLLT, is the high frequency of patient recall. The aim of the study was to evaluate and compare the amount of molar anchorage loss accompanying canine retraction, by employing two LLLT protocols, involving a high and a low application frequency.Materials and Methods: Sixteen patients were enrolled, in which the therapeutic extraction of maxillary 1 st premolars was required for orthodontic treatment, with subsequent canine retraction. Patients were equally and randomly divided into 2 groups. In Group A, LLLT was randomly administered to one side of the maxillary arch on days 0, 3, 7, 14, and then every 2 weeks, while in Group B, one side of the maxillary arch was randomly selected for LLLT application every 3 weeks. The administered LLLT was a Diode laser with a 980 nm wavelength. Canine retraction was carried out using closed-coil springs, with 150 grams of force, and the amount of mesial molar movement was checked every 3 weeks, over the 12-week study period.Results: Equivalent amounts of mesial molar movements have been displayed with and without LLLT application, in both study groups. Also, no significant differences have been documented between the laser sides in groups A and B. Conclusion: Molar anchorage has not been augmented by LLLT, whether applied with a high frequency, or with less frequent applications coinciding with the follow-up visits.