| Objective:Many studies indicate that the effects of tooth extraction is significant for profile changes,which can improve the surface protrusion in a certain extent,but previous reports are mostly on the comparative study of effects of different extraction modes on profile changes,little research on the comparative analysis of different vertical facial profile changes with the same extraction model after treatment,while different vertical facial types have different characteristics in the depth,height,width of basifacial 1/3,and growth will have a certain impact on the treatment results.Therefore,the common clinical adolescent patients of skeletal class I Angle class II division I was selected,measured the before treatment Cephalometric radiographs and lateral Cephalometric radiographs,analyse the treatment results of high angle,average angle patients with extraction of four first premolar,hard tissue and soft tissue profile changes of 1/3 surface(the surface depth)differences of high angle,average angle of two vertical facial types of tooth extraction,to provide a reference for the design of clinical treatment.Methods: From December 2016,in the orthodontic department of Stomatology Hospital Affiliated to Southwest Medical University,collected the patients which had end their treatments,in accordance with the inclusion criteria to select 60 patients of skeletal class I Angle II class I,including 30 high angles(males 11 cases,females 19 cases,before treatment the average age was 15.5 years,after treatment the average age was 18 years),30 normal angles(male 15 cases,female 15 cases,before treatment,the average age was 15 years,the average age was 17.5 years old after treatment),through fixing points and tracings on the before-treatment and after-treatment X-ray cephalometric of normal angles and high angles,measure the hard and soft tissue changes of basifacial 1/3,and measure the related indicators(Before treatment,the measured value was T1,and the measured value was T2 after treatment):(1)indicators of hard tissue: SNA/SNB/ANB/NP-FH/ NA-PA/SNP/ chin hard tissue /U1-SN/ L1-MP/ U1-L1;(2)indicators of soft tissue: FC A/NLA/ chin lips angle /chin soft tissue / soft tissue chin thickness /UL-E/LL-E.Analysed the data by statistics,comparative analyse the vertical facial appearance changes of two different after treatment with tooth extraction.Results:(1)After the treatment,the measured of SNA/SNB/ANB/ L1-MP/NA-PA decreased,|T2-T1|: high angle group > normal angle group,there was no significant difference between the two groups(P>0.05);The measured values of NP-FH/SNP/U1-SN/U1-L1/ hard tissue chin protrusion increased after treatment,changes of U1-L1/U1-SN/ hard tissue Chin protrusion|T2-T1|: high angle group >average angle group,the high angle group is less than the average angle group,no significant difference between the groups(P>0.05).(2)soft tissue chin thickness decreases,FCA increases,the high angle group is less than the low angle group;after the treatment,NLA/ chin angle angle / soft tissue chin degree /UL-E/LL-E measurement value increases,the high angle group is greater than the average angle group,except UL-E(P<0.05)index,all the indicators measured values between the two groups had no statistical significance(P>0.05).Conclusion:(1)in the same extraction treatment patterns,the high angle's basifacial 1/3 soft and hard tissue surface depth increasing greater than the average angle in a degree,except the distance changes in UL to E line(P<0.05),the other Appearance changes showed no significant difference(P>0.05).(2)The soft and hard tissue pogonion grew forward,shows that the skeletal class I Angle II class I type of adolescent orthodontic patients' s basifacial 1/3 change is a common effect of orthodontic treatment and growth results.(3)For the high angle patients,in the treatment process,we should always pay attention to upper and lower anterior teeth retraction,upper lip position controlling and so on,to avoid vertical height increasing,mandibular clockwise rotation,anterior teeth retraction appears excessive,upper lip retraction of the “orthodontic face ",and should strengthen the communication with patients before treatment,during the treatment and after the treatment,which can make the patients have a certain understanding and acceptance of the surface after treatment. |
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