The effect of low-level laser therapy on tooth movement during canine distalization.

The aim of the study is to determine the effects of low level laser therapy on tooth movement during canine distalization by evaluating IL-1ß, TGF-ß1 levels in gingival crevicular fluid. Maxillary first premolars of the 15 Angle Class II division I patients (12-19 years old) were extracted. Right maxillary canines were distalized by standard protocol as control group whereas the left maxillary canines distalized by laser application. A gallium-aluminum-arsenide diode laser with an output power of 20 mW was applied as five doses from the buccal and the palatal side on the day 0, and the 3rd, 7th, 14th, 21th 30th, 33st, 37th, 60th, 63th, and 67th days. Gingival crevicular fluid samples were obtained with filtration paper at the initial, 7th, 14th, and 21th days, and the IL-1ß and TGF-ß1 cytokine levels were analyzed. Orthodontic models and periodontal indices were taken initially and on the days 30th, 60th, and 90th of canine distalization period. Tooth movement was assessed by scanning models (3Shape). The amount of tooth movement in the laser group was 40% more than the control group. First day IL-1ß levels were statistically higher than initial and 21st day levels (P= 0.003, P = 0.012). The rise in IL-1ß levels caused the negative correlations between 7th day IL-1ß and 21st day TGF-ß1 levels describes the tissue effects of laser application. Periodontal indices showed no sign of gingival inflammation during canine distalization period. As conclusion, laser does accelerate tooth movement and could shorten the whole treatment duration.

Experimental tooth movement and photobiomodulation on bone remodeling in rats.

Photobiomodulation (PBM) is a therapy induced by a specific type of laser that affects biologic systems through non-thermal ways. The study of its basic mechanism has gained interest since little is known about the causes of the different effects of this treatment. In the present study, we investigated the action of the PBM application rate changes in the peri-implant tissues in rats subjected to tooth movement in different periods. Wistar rats (±250 g) received an apparatus in the region of the central incisors superiors tightly (70 g) or not, and they were also subjected to one or three PBM sessions. After 7 or 14 days, the rats were subjected to euthanasia and the jaws were dissected and processed for histology. For analysis, serial sections were made that were stained by Picrosirius Red for analysis of collagen fibers, Masson's trichrome for newly formed bone scan, and Hematoxylin-Eosin for quantification of osteoblasts. PBM applied in one or three sessions increased the population of osteoblasts. Still, the application of three sessions of PBM increased the density of collagen fibers and new bone formation compared to the controls. An increase was observed in the interincisal distance in irradiated groups with three PBM sessions and the application of force for both 7 or 14 days. These findings suggest that PBM can contribute positively to the orthodontic movement. So the laser therapy can be used as an adjunct procedure to be performed concurrently for orthodontic treatment in the dental clinic.

Effect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.

The aim of this experimental study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT), on the rate of orthodontic tooth movement (TM) and orthodontically induced root resorption, in rats. Twenty male 12-week-old Wistar rats were separated into two groups (control and LPT) and 50 cN of force was applied between maxillary left molar and incisor with a coil spring. In the treatment group, LPT was applied with an energy density of 20 mW/cm(2) over a period of 10 consecutive days directly over the movement of the first molar teeth area. The distance between the teeth was measured with a digital caliper on days 0 (T0), 10 (T1), and 21 (T2) on dental cast models. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. Mann-Whitney U and Wilcoxon tests were used for statistical evaluation at p < 0.05 level. TM during two different time intervals (T1-T0 and T2-T1) were compared for both groups and a statistically significant difference was found in the LPT group (p = 0.016). The TM amount at the first time period (1.31 ± 0.36 mm) was significantly higher than the second time period (0.24 ± 0.23 mm) in the LPT group. Statistical analysis showed significant differences between two groups after treatment/observation period (p = 0.017). The magnitude of movement in the treatment group was higher (1.55 ± 0.33 mm) compared to the control group (1.06 ± 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 ± 0.066 in the LPT group and 0.494 ± 0.224 in the control group. Statistically significant inhibition of root resorption with LPT was determined (p < 0.001) on the TM side. The LPT method has the potential of accelerating orthodontic tooth movement and inhibitory effects on orthodontically induced resorptive activity.