The Cephalometric Changes Of The Morphology Of The Soft-tissue Profile After Extraction In Classâ…¡ Division â…  Malocclusion On Early Permanent Dentition

Objective:This study was designed to compare the features of the soft tissue profile in classⅡdivisionⅠmalocclusion on early permanent dentition before and after different extraction treatments and explore the influences of extraction treatments on facial profile and soft tissue balance.Methods:80 cases of patients with classⅡdivisionⅠmalocclusion on early permanent dentition were selected at random from orthodontic division of Affiliated Hospital Medical College Qingdao University.We derided them into 4 groups according to different extraction treatments.Measure 18 soft tissue indexes of Cephalometric before and after treaments,and analyse these data by SPSS 13.0.Results:①In the first premolar extraction group,there was a significant decrease in Ls-SnPos,Li-SnPos,SNsSn,SNsSi,H angle(P＜0.01) and thickness of symphysis(P＜0.05),while a notable increase in Cm SnLs,Si-H(P＜0.01),and FH-NsPos(P＜0.05).②In the second premolar extraction group,SNsSn,Ls-SnPos,Li-SnPos reduced obviously(P＜0.05).③In maxillary frist premolar and mandibular second premolar extracted group,Cm SnLs increased and SNsSi decreased significantly(P＜0.01),H angle,Ls-SnPos,Li-SnPos reduced(P＜0.05).④In nonextraction group, FH-NsPos increased(P＜0.05),CmSnLs decreased(P＜0.05).⑤There were statistic significances lying in SNsSi,Ls-SnPos and Li-SnPos between the 4 groups(P＜0.01).Occlusions:①Extraction treatments can improve the soft tissue profile of classⅡdivisionⅠmalocclusion on early permanent dentition.②Significance changes lies in Ls-SnPos and Li-SnPos in different treatment groups.The changes of Li-SnPos are only related to whether extraction,but not the methods of extraction.