Abstract: Objective: To establish a recurrence curve after tooth movement in rats with low-energy laser and other interventions, and to explore the role of low-energy laser in orthodontic preservation. Methods: Sixty wistar rats were randomly divided into four groups. After the first molar proximal-to-medium movement model was established by the active treatment, the four groups were individually subjected with: no treatment (group B), low-energy laser irradiation (group L), fixed retention (group R), and fixed retention with low-energy laser irradiation (group RL). 3-shape three-dimensional scans were performed every other day to establish a recurrence curve. Overlap and describe analysis of the four groups of curves were performed. Results: The recurrence rate of molar movement in group L was significantly higher than that in group B. The recurrence rate in RL group was significantly lower than that in group R (P<0.01). Compared with group R, the recurrence period was significantly shorter in group RL. Conclusion: After the active correction of the rat's molar, applying the holding device to fix the position of the tooth and applying low energy laser irradiation can shorten the retention period and reduce the recurrence.

Key words: Low-level energy laser, Orthodontic retention, Tooth movement, Recurrence