高嘉澤KAO, CHIA-TZE林敬主DEVELAS, DEODEODEVELAS牙醫學系碩士班2026-03-172030-08-2720252025-07-17https://handle.ncl.edu.tw/11296/5a966ehttps://scholars.csmu.edu.tw/handle/123456789/5650Objective:This study aimed to evaluate the effect of low-level laser therapy (LLLT) using a diode laser on orthodontic tooth movement (OTM) in rabbits undergoing treatment with clear aligners. The research also assessed histological changes, osteoclastic activity, and body weight as indicators of biological and systemic responses to laser therapy.Materials and Methods:Twenty-one male New Zealand White rabbits were divided into three groups: a laser-treated group, a positive control group (aligners only), and a negative control group (no treatment). Custom clear aligners were fabricated using intraoral scans and 3D printing, inducing 0.20 mm movement per tooth per aligner. The laser group received 5 J/cm² diode laser irradiation at each aligner replacement (days 1, 3, and 5). Tooth movement (diastema) was measured on days 3, 5, and 7. Histological assessments using H&E, Masson’s Trichrome, and TRAP staining were conducted to evaluate tissue remodelling, osteoid formation, and osteoclastic activity. Independent t-tests were used for statistical analysis.Results:Both experimental groups exhibited measurable diastema changes; the laser group showed a trend toward greater tooth movement at days 5 and 7, though differences were not statistically significant. At day 3, the laser group experienced significantly less weight loss compared to controls (p = 0.006), suggesting reduced physiological stress. Histological findings revealed enhanced collagen maturation, increased cellularity, and earlier osteoid deposition in laser-treated samples. TRAP staining demonstrated earlier and more robust osteoclastic activity in the laser group. However, undermining resorption patterns were observed, potentially due to excessive force from the 0.20 mm per-tooth aligner increments, particularly in rabbits with thin PDL and small root dimensions.Conclusion:While diode laser therapy did not produce statistically significant acceleration of orthodontic tooth movement over a short duration, it facilitated favorable biological responses and improved systemic tolerance. These findings highlight the potential of LLLT as a supportive adjunct in aligner-based orthodontics. Further studies with larger sample sizes, longer observation periods, and refined laser protocols are needed to validate its clinical efficacy.Photobiostimulationclear aligner therapyAnimal StudyDiode LaserLLLTthesis