Study On The Changes Of Soft And Hard Tissue Profile After Two Different Extraction Treatments For Class ? Division 1 Adolescent Patients

Objective:To evaluate the soft and hard tissue profile changes in class II division 1 adolescent patients with two different premolar extraction teatments and provide reference for clinical treatment.Methods:A total of 60 class II division 1 adolescent patients treated at the Department of Orthodontics,School and Hospital of Stomatology,Jilin University between 2008 and 2016,were included,and they were divided into groupA and groupB based on different premolar extraction protocols.Patients in groupA(13.31±1.25yrs)were extracted 4 first premolars whether patients in groupB(13.03±1.31yrs)were extracted 2 maxillary first premolars and 2 mandibular second premolars.Pretreatment(T1)and posttreatment(T2)lateral cephalograms of 60 adolescent patients were traced,measured and digitized.The soft and hard tissue data before and after treatment was collected and the variables were calculated in both groups.SPSS22.0 software package was used for statistical analysis.Paired t-test was performed to compare the differences of the data between T1 and T2 in both groups.And the differences of variables between the two groups were compared by independent t-test.Results:1.As for hard tissue,Overjet,SNA,ANB,U1-NA,U1-NA(mm),U1 SN,NA-PA,A-NP reduced significantly,U1-L1,Pog-NB increased significantly in both groups.2.As for soft tissue,FCA increased significantly,H-angle and other items which represent the convexity of the upper and lower lip reduced significantly in both groups.3.There was no significant difference in soft and hard tissue change between the two groups.Conclusion:1.The convexity of soft and hard tissue was decreased significantly after both extraction treatments,and the convex profile was improved.2.There was no significant difference in soft and hard tissue change in patients treated with two different extraction teatments.