Comparison Of Corticision And Micro-osteoperforations To Accelerate Orthodontic Tooth Movement In Rats

Objective:Corticision and micro-osteoperforations were used to intervene in the mesial movement model of orthodontic teeth in rats to compare the tooth movement distance and modeling time difference among groups.Then,the changes of periodontal tissue morphology of rats,the expression of osteoclast-related factors in periodontal ligament and the changes of bone-related parameters under different intervention measures were observed.In order to discuss the difference between the two different surgical methods and provide a better choice and theoretical basis for clinical accelerated tooth movement.Methods: Eighty-one SD rats were randomly divided into 3 groups: 27 rats in the TM group(orthodontic group),27 rats in the CO group(orthodontic+corticision group),and 27 rats in the MOPs group(orthodontic+micro-osteoperforations group);the modeling time of each group was recorded.In each group,9 rats were sacrificed on the 3rd,7th,and 14 th days after modeling.After extraction of the right maxillary first molar,the periodontal ligament tissue was scraped to detect the expression of receptor activator of nuclear factor-κb ligand(Rankl)and macrophage colony-stimulating factor(M-csf)cytokines by real-time quantitative reverse transcription pcr(q RT-PCR);the rest of the rats were used for micro-computed tomography(Micro CT)scanning of tooth movement distance,bone volume fraction(BVF)and bone mineral density(BMD);hematoxylin-eosin(HE)staining was used to observe the changes of tooth and periodontal tissue morphology,as well as tartrate-resistant acid phosphatase(TRAP)staining to calculate the number of osteoclasts.Results: 1.Comparing the modeling time of single rats in each group: it was found that the modeling time of CO was significantly longer than that of TM group and MOPs group(p<0.05).2.HE staining of periodontal tissue on the pressure side : on the 7th day,the MOPs group and CO group had less hyaline degeneration,but more osteoclasts and bone resorption lacuna than the TM group;on the 14 th day,more osteoclasts were still found in the bone resorption pits in the CO and MOPs groups.3.TRAP staining on the pressure side: on the 7th day,the number of osteoclasts in each group reached the peak,and the number of osteoclasts in the MOPs group and the CO group was greater than the TM group(p<0.05);on the 14 th day,the number of osteoclasts in the periodontal ligament decreased to a certain extent,the CO group was larger than the TM group(p<0.05).4.The relative expression of M-csf mRNA: on the 3rd day,the M-csf mRNA expression in the MOPs group was higher than that in the TM group(p<0.05),on the7 th day,the expression levels of the MOPs group and CO group were higher than those in the TM group(p<0.05),and on the 14 th day,there was no difference among the groups.5.The relative expression of Rankl mRNA: on the 3rd day,there was no significant difference among the groups;on the 7th day,the MOPs group and the CO group were higher than the TM group(p<0.05);on the 14 th day,the CO group had higher expression than the TM group(p<0.05).6.Micro CT measurement of tooth movement distance: at 3 days,there was no significant difference in the movement distance between groups;at 7 and 14 days,the movement distance of the CO group was greater than that of the TM group(p<0.05);at 14 days,the MOPs group was greater than the TM group(p<0.05),and the CO group was greater than the MOPs group(p<0.05).7.Calculation of bone volume fraction: on the 7th day,the CO group reached the lowest and was smaller than the TM group(p<0.05).On the 14 th day,the bone volume fraction in the CO group was smaller than that in the TM group(p<0.05).8.Bone density: there was no difference among the groups at 3 days;the CO group and MOPs group reached the lowest point at 7 days,and the bone mineral density decreased compared with the TM group(p<0.05);at 14 days,the CO group was still lower than the TM group(p<0.05).Conclusion:1.Micro-osteoperforations and corticision can help clear periodontal ligament hyaline tissue,increase the rate of bone resorption and the expression of related inflammatory factors,reduce alveolar bone density,and achieve the purpose of accelerating orthodontic tooth movement.2.There is no significant difference between corticision and micro-osteoperforations in inducing regional acceleratory effect,and it takes less time than corticision,indicating that micro-osteoperforations can accelerate rats tooth movement in a more convenient and minimally invasive way.