Effect of Low-Energy Nanosecond Laser Therapy on Reparative Osteogenesis in vivo

The aim of the study was to assess the effect of low-intensity pulsed laser radiation on reparative osteogenesis of the jaw bones in the in vivo experimental study.

Materials and Methods. The experimental study was performed on 70 mature male Wistar rats whose lower molar was moved using an orthodontic spring for 21 days. A laser device with unique radiation parameters in a nanosecond pulsed mode of radiation with a wavelength corresponding to the oxygen absorption peak in the tissues was used for treatment. In the control group, laser treatment was not applied. To confirm the effect of laser radiation with the selected parameters on the stimulation of bone tissue remodeling, a morphological study was carried out followed by a morphometric study with a quantitative assessment of osteoclasts in the periodontal ligament on the border with the alveolar bone and in resorption lacunae.

Results. Already on the third day of the experiment, on the pressure side in the experimental group there was noted dilation and pronounced hyperemia of the periodontal ligament vessels, the appearance of a large quantity of osteoclasts on the border with the alveolar bone as compared to the control group. On day 7, the activation of fibroblasts, osteoblasts, and cementoblasts with the formation of new tooth root cement was noted on the pressure side, while a new cement formation in the control group was observed only on day 14 of the experiment. On day 21, in the experimental group, almost completely regenerated bone tissue of the alveoli was noted; in the control group, at this stage of observation, marked diffuse inflammatory infiltration of leukocytes with an admixture of lymphocytes and macrophages surrounding the fragments of the partially resorbed alveolar bone was seen.

Osteoclasts and osteoblasts are involved in the processes of bone tissue remodeling. Acceleration of bone resorption is of greater significance on the medial side in the direction of the tooth movement, whereas the regeneration processes are more important on the distal side. Morphometric examination showed over a 1.5-fold increase in the number of osteoclasts in the experimental group compared to the control group at all stages of observation.

Conclusion. Application of low-energy pulsed laser radiation with the given parameters accelerates bone tissue remodeling and contributes to neovascularization and filling the periodontal ligament and adjacent alveolar bone tissue with blood.

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Bazikyan E.A., Chunikhin A.A., Chobanyan A.G., Akhmazov E.V., Zhuruly G.N., Sahakyan M.Y., Zayratyants O.V. Effect of Low-Energy Nanosecond Laser Therapy on Reparative Osteogenesis in vivo. Sovremennye tehnologii v medicine 2019; 11(2): 44, https://doi.org/10.17691/stm2019.11.2.06