The influence of two photobiomodulation protocols on orthodontically induced inflammatory root resorption (a randomized controlled clinical trial).

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 .

A randomized controlled trial evaluating the effect of two low-level laser irradiation protocols on the rate of canine retraction.

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-1ß (IL-1ß) 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-1ß 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-1ß levels on the compression sides.

Anchorage loss during canine retraction using intermittent versus continuous force distractions; a split mouth randomized clinical trial.

OBJECTIVES: The aim of this study was to evaluate the anchorage loss, amount and time of canine retraction, and canine tipping concomitant with periodontal ligament distraction (PLD) using intermittent and continuous forces. MATERIALS AND METHODS: This was a split mouth randomized clinical trial involving 30 patients in need of first premolar extraction. For each patient, one side was randomly allocated to receive a screw-based dental distractor, and the other side a continuous force coil spring distractor. Molar and canine movements were recorded on study casts using the rugae as reference. Changes in the long axis of the canines were evaluated from pre- and post distraction panoramic radiographs. RESULTS: On the screw side, molars moved mesially 2.5±0.9 mm. The canine tipped distally a mean of 10.5°±3.1°. The average time needed for canine retraction was 5.3±1.3 weeks. In the coil side, the molar mesial movement was not statistically different from the screw group (2.8±1.5 mm). The canine moved bodily with a mean distal tip of 0.27°±1.75° in a period of 27.8±6.6 weeks. CONCLUSIONS: Anchorage loss occurs with dental distraction using either intermittent or continuous force. No significant difference in anchorage loss was found with either type of force. The surgical intervention did not shorten the time needed for canine retraction using the continuous force. Continuous force leads to slow bodily retraction of the canine unlike the intermittent force which leads to rapid tipping of the canine.