Comparative Study On Alignment Stage For Angle ?~1 Malocclusion By PASS And DAMON Self-ligature Technology

Objective:To compare the soft tissue and skeletal tissue changes in Angle II ~1malocclusionon the alignment stage,the patientd were treated by PASS and DAMON self-ligature orthodontic techniques,which can provide reference for the selection of clinical appliances.Methods:Thirty Angle II ~1 Han patients who received orthodontic treatment from September 2016 to September 2018 in the Department of Orthodontics from the Fifth Affiliated Hospital of Xinjiang Medical University.They were randomly divided into PASS group and DAMON self-ligature brackets group,with 15 cases in each group.cephalometric X-ray and lateral cephalometric films were taken before and after Leveling and aligning.Relevant soft and skeletal tissue indexes were measured and the results were analyzed by SPSS 17.0 The changes of soft and skeletal tissues were compared between the two groups.Results:(1)The average time of alignment in PASS group and DAMON self-ligature bracket group was 5.28 months and 5.36 months,respectively.There was no significantly difference between the two groups(P>0.05);(2)The changes of skeletal and soft tissues after alignment,the PASS group,The index of U1-NA angle,U1-L1 angle,U1-AP distance,L1-AP distance,U6E-PP distance,L1-MP distance,NsLs-FH(dg),CmSn-Ls(dg),LL-EL distance,they changed significantly(P<0.05).The DAMON self-ligature brackets group,The index of U1-L1 angle,U1-AP distance,L1-AP distance,L1-MP distance,CmSn-Ls(dg),UL-EL distance.they had statistically difference before and after alignment(P<0.05);(3)The changes of U6E-PP distance,UMC-PPV distance and L1-MP distance between PASS group and DAMON self-ligature group had statistically difference after alignment(P<0.05).Conclusion:Both PASS and DAMON self-ligature orthodontic techniques can quickly align dentition and provide a favorable guarantee for closing extraction space and adjustment in the later stage,compared the two group,the PASS orthodontic technique can better control molar anchorage and improve convex profile combined with physiological strength on the alignment stage.