Condylar Morphological Changes Before And After Orthodontic Treatment For Adult Angle Class Ⅰ Patients:a Radiographic Study

Objective The aim of this study was to evaluate the condylar morphological changes in adult Angle Class Ⅰ patients before and after orthodontic treatment using a Cone-beam computed tomography(CBCT).Methods Images of twenty-five adult Angle Class I patients(5 males,20 females,age from 18 to 38years old,average age 24.2years old)who have no temporomandibular symptom were involved in this study.CBCT datas were saved as digital Imaging and Communications in Medicine(DICOM),and MimicsTM 10.01 software was used to reconstruct the three-dimensional condyle.Three-dimensional condyles were superimposed pre-and post-treatment to compare the changes of condylar surfaces,Measurements of condylar morphology included:Condylar Height(H1),Height of Condylar Head(H2),Height of Condylar Neck(H3);Area of Maximum Axial Plane(A1),Area of Maximum Sagittal Plane(A2);Bone Density of Maximum Axial Plane(Hounsfield Unit 1,HU1),Bone Density of Maximum Sagittal Plane(Hounsfield Unit 2,HU2),Bone Density of Three-dimensional Condyle(Hounsfield Unit 3,HU3),Bone Density of Three-dimensional Condylar Head(Hounsfield Unit 4,HU4);Volume of Three-dimensional Condyle(V1),Volume of Three-dimensional Condylar Head(V2)before and after orthodontic treatment.Difference between pre-and post-treatment measurements received test of normality.Paired t test was applied for comparison between pre-and post-treatment condylar metric analysis using SPSS 19.0 software package.P value was set at.05.Result1.There is no statistically significant difference of Condylar Height(H1),Height of Condylar Head(H2),Height of Condylar Neck(H3)between pre-and post-treatment(P>0.05).(H1 pre-treatment 17.76±2.53mm,post-treatment 18.21±2.80mm;H2 pre-treatment 8.25±2.14mm,post-treatment 8.36±2.00mm;H3 pre-treatment 10.62±2.32mm,pos-ttreatment 10.77±22.39mm);2.In comparison with pre-treatment,Area of Maximum Axial Plane A1(pretreatment 294.67±36.83mm2,posttreatment 282.47±39.78mm2),Area of Maximum Sagittal Plane A2(pretreatment111.28±40.12mm2,posttreatment 104.13±28.03mm2)decreased significantly(P<0.05);3.In comparison with pre-treatment,Bone Density of Maximum Axial Plane HU1(pre-treatment 592.84±86.31hu,post-treatment 514.00±101.06 hu),Bone Density of Maximum Sagittal Plane HU2(pre-treatment 589.31±115.86hu,post-treatment 511.53±109.22hu),Bone Density of Three-dimensional Condyle HU3(pre-treatment 751.62±83.32hu,post-treatment 658.11±90.36hu),Bone Density of Three-dimensional Condylar Head HU4(pretreatment 601.93±99.78hu,posttreatment524.36±96.80hu)decreased significantly(P<0.05).4.In comparison with pre-treatment,Volume of Three-dimensional Condyle V1(pretreatment 1799.60±335.83mm3,posttreatment 1722.87±348.77mm3)decreased significantly(P<0.05).There is no statistically significant difference of Volume of Three-dimensional Condylar Head V2(pretreatment 656.82±301.57mm3,posttreatment 676.11±267.58mm3)between pre-and post-treatment(P>0.05).5.Superimposition of pre-and post-treatment models show both bone resorption and bone formation exit on the condylar surface.Conclusion1.Area of maximum axil plane,and maximum sagittal plane in adult Angle Class I malocclusion patients decreased after treatment.2.Bone density of maximum axil plane,maximum sagittal plane,three-dimensional condyle and three-dimensional condylar head in adult Angle Class I malocclusion patients decreased after treatment.3.Volume of three-dimensional condyle in adult Angle Class I malocclusion patients decreased after treatment.4.Superimposition of pre-and post-treatment models showed that condylar morphology had undergone remodeling after orthodontic treatment...