| The purpose of this study is to investigate the following factors:1.To analyze and compare the facial proportions,the changes and symmetry of craniofacial bone before and after orthognathic surgery by collecting the three dimensional spiral CT data of adult patients with skeletal class Ⅲ malocclusion and to evaluate the effect of orthognathic surgery.By collecting the three dimensional spiral CT data of adult patients with skeletal class Ⅲ malocclusion for the analysis of the facial proportion of patients the comparison of the changes and symmetry of craniofacial bone before and after orthognathic surgery,and the effect of orthognathic surgery was evaluated.2.To compare the relationship of the condylar position to the joint fossa and the angle of each direction of condyle before and after the orthognathic surgery in patients with skeletal class Ⅲ malocclusion,to understand the effect of orthognathic surgery on the temporomandibular joint(TMJ)of skeletal class Ⅲ malocclusion and the adaptability of TMJ to the orthognathic operation.3.To analyze and compare the longitudinal study of quality of life of the patients with skeletal class Ⅲ malocclusion before,during and after the combined treatment of orthodontic and orthognathic surgery,and to evaluate the postoperative effect by comparing with the normal control group by using OHIP14 and OQLQ survey.Materials and methods32 patients with skeletal class III malocclusion were collected from 2014 to 2019,of which 13 males and 19 females were treated with the combined treatment of orthodontic and orthognathic surgery in the center of orthognathic center of Aaffiliated Oral Hospital of Guangxi Medical University,with an average age of 24.10 ± 3.67 years.Study 1: Computer scans: Phillips 256-layer ultra-fast spiral CT system(provided by Phillips Company,Netherlands,and no.923 Hospital of PLA(the third and Third Hospital of PLA).CT data(DICOM)were obtained before and 6months after operation,and 3D reconstruction model was established by using plan CMF 3.0 software.The three-dimensional changes of craniofacial bone were analyzed before and after operation and 6 months after surgery and between men and women,and the asymmetry of facial and mandible was evaluated.Spss20.0 was used to analyze the independent sample t test and paired t-test.Study 2: The axial angle of temporomandibular joint(TMJ)was measured by using the software of plan CMF 3.0 and the condyle position was analyzed on three planes.The measurement was carried out on axial(horizontal),coronal and sagittal planes.In addition to the axial angle of the condyle,the postoperative changes of the condyle relative to the anterior and posterior position of the joint fossa were evaluated on the sagittal plane.Spss20.0 chi square test,independent sample t test and paired t-test were used for statistical analysis.Study 3: The oral health impact scale(OHIP-14)and quality of life questionnaire(OQLQ)were analyzed by the time points of 32 patients with orthognathic patients before treatment(T0),complete orthodontic decompensation(T1)and 6 to 8 months(T2)after operation.24 healthy volunteers were randomly selected as control group(TC),and the influence of orthognathic operation on the quality of life of patients and the changes between experimental group and control group were analyzed.The numerical variables between the experimental group and the control group were compared by Mann Whitney U test,and the scores of T0,T1,T2 and control group(TC)in OHIP-14 were compared by generalized estimation equation.The scores of T0,T1 and T2 in OQLQ were compared.The classification data was expressed in percentage(%),and the chi square test was used to evaluate.SPSS was used for all data20.0 statistical analysis.Result1.According to statistical analysis,the linear indexes of male and female patients before operation were statistically different(P < 0.05),such as Zy-Zy137.3 ± 8.1mm,female 131.8 ± 5.1mm,male N-ANS57.8 ± 3.8mm,female 53.4 ± 3.1mm.In the aspect of facial proportion of male and female patients,FM FM / N-Me,male 0.79 ± 0.04,female 0.84 ± 0.05;ZY ZY / N-Me,male 1.02 ± 0.07,female 1.08 ± 0.06;ZY-ZY / FM-FM,male 1.29 ± 0.06,female 1.25 ± 0.03,the difference of these three indicators was statistically significant(P < 0.05)..2.After orthognathic surgery,there were significant differences in the linear indexes of go GN,ANS-Me,N-Me and Go-Go(P < 0.05).In the aspect of the postoperative facial proportion,Go-Go / N-Me changed from 0.84 ± 0.35 to0.80 ± 0.19 after operation.The difference was statistically significant(P < 0.05).It suggested that the ratio of craniomaxillofacial bone and the asymmetry of mandible were improved significantly after treatment.2.The position of condyle in the joint fossa of male and female patients was significantly different before operation.The proportion of male centric condyle position was 61.5%,the anterior condylar position accounted for 15.4%,the posterior condyle position accounted for 34.6%;the female centric condyle position accounted for 44.77%,the anterior condylar position 26.3% and the posterior condylar position 47.4%.The difference of the axial angle of the condyle was statistically significant(P < 0.05),the axial angle of the left condyle was 67.5 ± 7.51 °,the axial angle was 65.6 ± 8.54 °,the axial angle of the right condyle was 65.5 ± 7.04 °,and the axial angle was 62.9 ± 9.36°.The results showed that the bilateral condyle had the tendency of inward transposition.There was no significant difference in axial angle between the two condyles in the coronary and sagittal directions(P > 0.05).3.according to OHIP-14 questionnaire,the average score of t0 to T1 was significantly higher than that of TC(P < 0.001),t0 score was 20.6 ± 3.5,T1 was22.9 ± 4.2,TC was 10.6 ± 2.6,and T2 was significantly decreased(P < 0.001),T2 score was 12.4 ± 3.1,reaching the same level as that of control group(P >0.05).For OQLQ,the overall score showed a significant increase between t0 and T1,t0 was 29.9 ± 4.5,T1 was 33.7 ± 5.5(P < 0.05),significantly decreased in T1-T2,16.45 ± 3.2 in T2,and t0-t2 significantly(P < 0.05).4.ConclusionThere are some differences in facial contour and facial proportion among different genders of skeletal class III patients.After the combined treatment of Orthodontics and Orthognathic surgery,the profile and proportion of craniomaxillofacial bone in patients with skeletal class Ⅲ malocclusion were improved obviously,and the facial asymmetry was also significantly improved,so the appearance of the patients was improved.After the treatment of adult skeletal class Ⅲ malocclusion,the condyle position had changed,moving forward or backward or away from the joint socket,and the condyle moved inward in the axial plane.But it did not cause the any discomfort of TMJ.After OHIP-14 and OQLQ investigation and analysis,the patients’ pre surgery orthodontic compensation have temporary adverse effects on the quality of life of patients.However,the combined treatment of orthodontic and orthognathic surgery can improve the quality of life of patients with skeletal class III malocclusion,and achieve the results nearly as those of the normal control group. |
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