The Research On Animal Experiment About Acceleration Of Tooth Movement Made By Ultrasound

Objective:We set up the rat orthodontics model successfully through choose SD rats.To observe the ultrasound can accelerate the tooth movement in a rat orthodontic model,this thesis makes a primary research on ultrasound stimulation,which had an influence on tooth movement and molecular mechanismsMethods:In this study,Orthodontic appliances were placed between the first molars and central incisors in the maxillary of rats.100 rats were randomly divided into 2 groups:traditional tooth movement group and ultrasound+tooth movement group.with 5 rats in each time point.The rats were sacrificed at different time points(t=1、3、5、7、14days),A group:morphological detection;the distances of tooth movement were measured,in other words,the distances between the first molar in the distal edge of the crest and the second molar in the mesial edge of the crest.HE staining observated histologically around the first molar.TRAP staining showing that TRAP-positive mononucleated and multinucleated cells were markedly induced at the compression side.Group B for molecular biology analysis.Using RT-PCR to assay TRAP、CTSK、JDP-2、NFACT-1 and Objective:BSP mRNA expression of periodontium of upper first molar on day 1、3、5、7、14、Results:(1)The test resluts for the distance of tooth movement:ultrasound significantly increased orthodontics tooth movement distances at day 5、7、14 compared with conventional orthodontic group(P<0.05);(2)Histological observation demonstrated the count of osteoclasts in the experimental group significantly more than the conventional orthodontic group at day 5、7、14(P<0.05);(3)The results of RT-PCR showed that the relative CTSK expression levels by ultrasound on day 5.7.14 were increased(P<0.05),while they had significant increase on day 14(P<0.01).The relative TRAP expression levels by ultrasound reached the peak levels on day 14.the difference was statistically significant(P<0.01).The expression of JDP-2 were significant increased on day 7 compared with conventional orthodontics group and showing peak values(P<0.01).The expression of NFACT-1 reached the peak levels on day 3(P<0.01),then begins to decrease,little increased on day 14.2.The expression fo BSP in ultrasound group were significantly higher than that of traditional orthodontic group,significantly increased at day 14 in traditional orthodontic group(P<0.01).the difference was statistically significant.Conclusions:(1)Ultrasound could accelerate the tooth movement,shortening the time of orthodontic time.(2)Ultrasound significantly and continue to increase the number of osteoclast formation in periodontal tissue,enhance the osteoblast activity,promote the reconstruction of alveolar bone tissue,the effect may be the cause of ultrasound could accelerate the tooth movement.