Objective: Accelerated tooth movement (TM) is achieved in orthodontics via corticotomy (CY) but with invasive surgical interventions. Minimally invasive CY using mini-implant may expedite TM. In this study, we developed a rat model to evaluate orthodontic TM with mini implant-assisted CY.

Methods: A split-mouth experimental design was utilized in six Sprague-Dawley rats with the CY left side and the sham right side of the maxillary 1st molars. 25g close-coiled springs were secured to both incisors and 1st molars. TM was observed by diastema measurement. Samples were analyzed by MicroCT, H&E and TRAP.

Results: Compared to the sham side, the CY side exhibited 30% greater TM, 10% greater BMD and 7% greater BV/TV. More osteoclasts were found in the CY side; 44% and 55% more in the total alveolar bone and pressure side bone, respectively.

Conclusions: Non-surgical method of CY using mini implant shortened TM and improved bone quality, demonstrating that the modified mini implant-assisted CY may shorten orthodontic treatment time.