Comparative evaluation of oral misoprostol and low-level laser therapy in orthodontic tooth movement in a rat model

To investigate the effects of low-level laser therapy and misoprostol on orthodontic tooth movement (OTM), external root resorption, root length, alveolar bone mineral density (BMD), and osteoclast activity.

Thirty-six female Wistar albino rats were divided into misoprostol, laser, and control groups. OTM was induced using a nickel-titanium closed-coil spring between the maxillary incisor and first molar for 21 days. Following euthanasia, tooth displacement, root length, root resorption, and BMD were analyzed using micro-computed tomography. BMD was assessed around the mesial root in tension, compression, apical mesial, and apical distal regions. Osteoclastic activity was evaluated immunohistochemically.

The laser and misoprostol groups showed greater OTM than the control group, without statistical significance (p > 0.05). Root length and root resorption did not differ significantly among groups (p > 0.05). BMD values were similar across groups (p > 0.05), although within-group comparisons showed higher values in tension areas and lower values in compression areas. Osteoclast counts were significantly higher in the laser group (p < 0.05).

Under the conditions of this study, low-level laser therapy did not result in a statistically significant increase in tooth movement; however, it may influence the cellular mechanisms underlying orthodontic tooth movement, as reflected by increased osteoclast activity, and may modulate bone remodeling without increasing root resorption. Although BMD tended to decrease in the compression areas and increase in the tension areas, the findings were inconsistent in the apical regions.