The Effect Of Controlled Root Movement On Stability Of Tooth Movement After Periodontally Accelerated Osteogenic Orthodontics

ObjectivesThe emergence and wide application of Periodontally Accelerated Osteogenic Orthodontic treatment provides a new treatment to lift the limitation of buccal movement of orthodontic teeth.But the long-term effects of periodontal accelerated osteogenic orthodontic treatment,the long-term stability of buccal movement of orthodontic teeth,and the effect of controlled root movement are rarely reported.In this study,we established a canine model of periodontal accelerated osteogenesis orthodontic treatment for posterior teeth buccal movement,and explored the effect of controlled root movement and cortical osteotomy combined with bone grafting on long-term stability of tooth movement in the process.Materials and Methods20 second premolars of 5 dogs aged 9～12 months were randomly divided into non-controlled root movement operation group,controlled root movement operation group,non-controlled root movement non-operation group,controlled root movement non-operation group and blank group.Cortical osteotomy combined with bone grafting were performed on the buccal side of the second premolar of the non-controlled root movement operation group and controlled root movement operation group after preparation and wearing of personalized teeth buccal movement device.Immediately after surgery the buccal movement model of posterior teeth were established:0.018inch stainless steel round wires were used in non-controlled root movement operation group and non-controlled root movement non-operation group,0.0215inch × 0.028inch stainless steel square wires were used in controlled root movement operation group and controlled root movement non-operation group and blank group.The orthodontic force of the blank group was 0g,;the orthodontic force of the other four groups was 100g.The orthodontic course was 10weeks.The CBCT was taken before the experiment,after 10 weeks of treatment,and after 6 months of maintenance.And the distance from midline,changes of tooth inclination,buccal/lingual alveolar ridge position of the second premolar were measured.TNF-α,IL-17,RANKL,OPG content in gingival crevicular fluid was detected.SPSS 22.0 statistics software was used for statistical analysis and P<0.05 indicated that the difference was statistically significantResultsFor the buccal movement of the posterior teeth assisted by periodontal accelerated osteogenesis orthodontic treatment under the light force system:1、the operation can accelerate tooth movement(P<0.05),reduce the degree of buccal inclination(P<0.05)and reduce buccal alveolar boon resorption(P<0.05).However,there was no significant difference in the degree of palatal alveolar bone resorption between the group with and without operation(P>0.05);2、the application of controlled root movement can decrease the tooth movement speed(P<0.05)and reduce the degree of buccal inclination(P<0.05),but it has no significant effect on the buccal and palatal alveolar boon resorption(P<0.05);3、during retention,the application of the operation and the application of the controlled root movement can reduced the recurrence distance(P<0.05);4、during orthodontics treatment,the application of operation can significantly influence the content of TNF-α,IL-17,RANKL,OPG in gingival crevicular fluid,and may affect osteoclast activity through the RANKL-OPG pathway to participate in periodontal tissue metabolism.ConclusionsFor the buccal movement of the posterior teeth assisted by periodontal accelerated osteogenesis orthodontic treatment under the light force system,in the orthodontic process,the operation can increase the stability of teeth after orthodontics treatment without changing the original tooth movement mode and reduce the absorption of alveolar ridge.Controlled root movement can reduce the degree of buccal inclination,increase the stability of teeth after orthodontics,but may slow down the speed of tooth movement.It is suggested that when the periodontal accelerated osteogenesis orthodontic treatment is applied,although uncontrolled root movement increase the efficiency of tooth movement,the controlled root movement is needed to reduce the recurrence after orthodontic treatment.Surgery may affect activity of osteoclast through RANKL-OPG pathways to take participate in periodontal tissue metabolism.Further experiments are needed to explore the mechanism in this process.