The Positional And Morphological Study On Condyle-fossa In TMJ Asymptomatic Adult Patients With Skeletal Class â…¢ Malocclusion

Objective:The aim of our study was to quantity measure condylar parameters and assesses condyle position within glenoid fossa of TMJ in TMJ asymptomatic adult patients with Class III malocclusions and normal occlusion on volumetric 3D imaging.Materials and Methods:The study group included 40 TMJ asymptomatic patients with skeletal Class III malocclusion (male:18, female:22, mean age 23.9±3.72years) and 40 healthy volunteers with normal occlusion as the controls (male:24, female:16, mean age 25.3±4.13years). All subjects are symptom-free who had no pathological temporomandibular joint changes as verified by lateral tomographic imaging. Their joints had optimum function with the starting and end points of all functional jaw movements coincident with maximum intercuspation. The pictures were reconstructed in three-dimensional (3D) using Mimics10.01 software rendering and measured in two dimension projection (2D) pictures, linear measurements examination was performed. The images obtained from the sagittal slices were used to quantify following condylar and glenoid fossa parameters: superior space, anterior space and posterior joint space; glenoid fossa width and height; tuberculum articulare angle; height and width of condyle, height of procesus condylaris. The images obtained from the axial slices were evaluated for possible asymmetries in size and position between the condylar processes associated with these malocclusions. Mean values were calculated separately for left and right side. The position of mandibular condyle was described as anterior, concentric or posterior according to Pullinger.Differences of the mean values were tested using paired t-test and X2-test。Results:1.The mean AS, SS, and PS values in skeletal ClassⅢgroup were 1.58 mm (SD±0.14mm),2.79mm (SD±0.17mm)and2.01mm (SD±0.16mm)on left side, respectively; and the mean AS, SS, and PS values on right side were1.57 mm (SD±0.15mm),2.80 mm (SD±0.18mm), and2.02mm (SD±0.16 mm), respectively; The mean AS, SS, and PS values in normal occlusial group were 1.69 mm (SD±0.23mm),2.84mm (SD±0.31 mm)and 1.94mm (SD±0.22mm)on left side, respectively;and the mean AS, SS, and PS values on right side were1.70 mm (SD±0.23mm),2.83 mm (SD±0.21mm), and1.95mm (SD±0.30 mm), respectively;There were statistically significant differences (p<0.01) between two study groups for AS on both sides;2.In the ClassⅢsample, there was no statistically significant difference between sides,46.25% anterior positioning and 53.75% concentric positioning of the condoyle was observed; however 7.5% anterior positioning and 92.5% concentric positioning of the condoyle was detected in normal occlusial groups;3.In the ClassⅢsample, the width of fossa glenoid on the left and left were 19.21±0.86mm and 19.24±0.85mm respectly,which is larger than that in normal occlusion (18.81±0.99mm,18.79±0.99mm,P<0.05); the angulations of the articular tubercle in the ClassⅢsample were significantly smaller than that in normal occlusion(31.53±1.96°,31.47±1.96°;33.19±1.82°,33.22±1.90°respectly P<0.01).the left and right height of condyle were 3.44±0.30mm and 3.46±0.29mm respectly, which is significantly smaller than that in normal occlusion(3.77±0.21mm,3.76±0.22mm respectly P<0.01). The height of procesus condylaris between two groups varied with statistical difference(ClassⅢsample:16.83±1.48mm,16.81±1.95mm;normalocclusion:15.90±1.3 0mm,15.89±1.32mm,respectly,P<0.05)4.On the axial slices, The left geometric center of the condylar processes to the midsagittal plane in the ClassⅢsample was larger than right(50.23±3.65mm,49.81±3.76mm, respectly P<0.05) and which were significantly smaller than that in the normal occlusion groups (52.82±4.30mm,52.68±4.21mm, respectly,p<0.01).Conclusion:1.On the spatial slices there was a smaller measure for anterior articular space in the ClassⅢsample. More than half of anterior position of the condyles in ClassⅢsamples was detected.2.There was a smaller condylar height and wider glenoid fossa comparing TMJ of ClassⅢpatients and normal samples; the larger height of procesus condylaris and smaller angulations of the articular tubercle were detected;3.0n the axial slices, there was significantly asymmetric on the left and right congdyle in the ClassⅢsample.