MATERIALS AND METHODS: Twenty-six Wistar rats underwent mesial orthodontic traction with a force of 50 g for 21 days. Following the application of the orthodontic appliance, the rats were randomly divided into two groups: a control group, which received a 0.3 µg saline injection, and the experimental FsHA group, which received 100 mg/0.3 ml of FsHA-NPs after thorough characterisation. Injections were administered immediately after appliance application and repeated at 7 and 14 days. Statistical analysis was conducted with a significance level of P ≤ 0.05.

RESULT: The experimental group exhibited a significant reduction in OTM at 7-, 14-, and 21-day post-force application. Additionally, a reduction in PDL width was observed in the mesiocervical and disto-apical regions of the mesial and distal roots of the first molar.