RESUMO
PURPOSE: To investigate the role of transforming growth factor-ß1 (TGF-ß1) in periodontal tissue reconstruction during rapid teeth movement through reducing resistance and distraction. METHODS: Twenty Beagle dogs were randomly divided into five groups according to time points: distraction for 5 days, 10 days, 15 days, retaining 10 days after distraction for 15 days, and retaining 90 days after distraction for 15 days. The mandibular first premolar was moved by using reducing resistance and distraction (experimental group) or conventional distraction (control group) randomly. For each group, tooth movement distance was measured and first premolar periodontal tissue pieces were obtained in scheduled time. Hematoxylin-eosin stain, Picric acid-Sirius red, and immunohistochemistry were performed. The data was analyzed by using SPSS 18.0 software package. RESULTS: The speed of tooth movement and periodontal reconstruction of the experimental group were significantly faster than the control group. TGF-ß1 positive expression in two groups had similar distribution area, and reached peak at most active stage of osteogenesis in both groups. But in different stages of distraction, the positive expression in the experimental group was significantly higher than the control group(P<0.05). CONCLUSIONS: Compared with conventional orthodontic method, reducing resistance and distraction can obviously increase the expression of TGF-ß1 of tension side of the distracted tooth, and accelerate periodontal tissue reconstruction.