Effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of BMP-2

The aim of the study was to investigate the effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of bone morphogenetic protein-2 (BMP-2). Adult male Wistar rats (n=30), with an age range of 14-15 weeks, and an average weight of 250+/-16 g were used. The animals were randomly divided into the control and observation groups. The rats in the control group were injected with 25-dihydroxyvitamin (1,25-dihydroxycholecalciferol) into their dental ligament. The rats in the observation group were placed with an orthodontic device between the first molar and central incisor in the maxillary. On the first day after animal treatment, piezosurgery stimulation was performed on the first molar in maxillary. The changes of the movement distance of the first molar and gum surface temperature on days 1, 3, 5, 7 and 14 were then compared. Immunohistochemical staining was performed to detect the expression of BMP-2 of periodontal tissue in the tension side of the first molar. Tooth movement distance in the observation group on days 5, 7 and 14 was significantly longer than that in the control group (p<0.05). The gum surface temperature of the observation group was elevated to some extent, peaking after 20 min. BMP-2 mRNA and protein levels in the observation group were significantly higher than those of the control group at days 3, 5, 7 and 14 (p<0.05). In conclusion, piezosurgery may significantly accelerate the movement of orthodontic alveolar bone tooth of rats and be associated with an increasing BMP-2 expression.