A Comparsion Study On The Changes Of Soft And Hard Tissues By Two Kinds Of Extraction Treatment Patterns In Angle's Class ? Division 1 Malocclusions

Objective:This study aims to use cephalometric X-rays to evaluate the hard and soft tissues change of Angle's Class ? division 1 malocclusion patients after tooth extraction orthodontic treatment and provide experimental results to help in making orthodontic treatment plan and treatment.Methods:According to the inclusion criteria,a total of 27 Angle's Class ? division 1malocclusion patients with tooth extraction orthodontic treatment were included and divided into two groups in this study.The group A consisted 13 patients who were extract four first premolars and two maxillary second molars(male 6 and female 9,age 14 to 16;average age 14.57±0.85 years,treatment time 18.14±1.67 months);The group B consisted 14 patients who were extract four first premolars and two maxillary third molars(male 7 and female 8;age 12 to 15;average age 13.64 ± 0.93years;treatment time 22.64 ± 0.84 months).The Face bow was used during the treatment.The before and after treatment X-ray cephalometric were introduced into the winceph8.0 software for measurement.Then,using SPSS22.0 to analysis data.Results:1.There was no statistical significance between the two groups before treatment(P>0.05),indicating that the two groups were comparable.2.After treatment,the distal movement of maxillary first molars in group A was greater than that in group B,and the height of S-Go in group B was higher than that in group A(P<0.05).There was no statistical significance in the changes of soft tissue,upper and lower incisors,and mandibular first molar(P>0.05).Conclusions:1.After two kinds of extraction patterns,the soft tissue profile convexity improved both in group A and group B;2.Distalization maxillary first molar after extract four first premolars and twosecond molars can achieve more space than that extract four first premolars and two third molars.