Effects of Low-Level Laser Therapy Versus Injectable Hyaluronic Acid Combined with Platelet-Rich Plasma on Orthodontic Tooth Movement

Abstract Background Accelerating orthodontic tooth movement (OTM) without compromising periodontal tissue integrity remains a substantial challenge in clinical orthodontics. Low-level laser therapy (LLLT) and biologic regenerative strategies have been explored to modulate periodontal tissue responses and alveolar bone remodeling. Aim To compare the effects of LLLT and a mixture of hyaluronic acid nanoparticles (HA-NPs) and platelet-rich plasma (PRP) on OTM and the associated histological changes in periodontal and alveolar bone tissues in rabbits. Methods Eighteen healthy adult male rabbits were divided into three groups: control, LLLT, and HA-NP/PRP. The LLLT group was irradiated with a 940-nm diode laser at six points around the maxillary incisors during orthodontic tooth movement. OTM and histological evaluations were assessed to evaluate periodontal ligament (PDL) width, osteoclast numbers, remodeled bone area, vascular area, and cellular activity. Results Mean OTM was 1.12 ± 0.08 mm in the control, 1.29 ± 0.10 mm in the LLLT, and 1.37 ± 0.12 mm in the HA-NP/PRP. OTM was statistically greater in both intervention groups, but the overall OTM was not statistically significant (p = 0.084). Histological analysis showed significant differences between groups in PDL width (p = 0.021), osteoclast number (p = 0.015), and area of remodeled bone (p = 0.008), with the maximum values reported in the HA-NP/PRP. Vascular area and cellular activity increased in the control, LLLT, and HA-NP/PRP groups, which suggests differences in the periodontal tissue response of the experimental groups Conclusion LLLT and HA-NP/PRP treatment were associated with histological changes compatible with periodontal tissue remodeling during OTM. However, these biological changes did not translate into a statistically significant difference in OTM. Additional studies with longer observational periods are required to elucidate the relationship between histological responses and OTM.