| Objectives: Mandibular deviation has a strong impact on the patients’aestheticism and function, it is very difficult for the adult patients who are ofskeletal class Ⅲ with mandibular deviation to be treated. The objective of thisstudy is to explore the change of condylar morphology and location in adultpatients by using cone-beam computed tomography (CBCT), so it can help toprovide clinical diagnosis, treatment designs.Methods: Twenty adult patients with skeletal class Ⅲ of mandibulardeviation (ten males and ten females), aged from18to31years old (average21.5years old) were selected as a deviated group from visiting in Dept. ofOrthodontics, Hospital of Stomatology, Hebei Medical University during Oct.2011to Oct.2012. The standards were followed:(1) Facial asymmetry and thechin deviation was more than2mm.(2) The midline of the maxilla and themandible were differed more than2mm.(3) The molar relationships weremesioclusion, and ANB<0°. At the same time, twenty student-volunteers ofHebei Medical University with normal occlusion (ten males and ten females)were selected as the normal group, the age range of the normal group was18to28years old (averaged20.95years), the standards were followed:(1) Facialsymmetry.(2) The midline of the maxilla and the mandible were aligning.(3)The molar relationships were neutroclusion, and0°≤ANB≤4°.(4) Normaloverjet and normal overbite. All the patients and volunteers were performedskull scanning by using CBCT, the materials obtained were applied Invivo5software to reconstruct three dimensional (3D) rebuilded images. They wereon3D rebuilded images that the anteroposterior diameter, the medialateraldiameter, the perpendicular height, the length of anterior slope, the length ofposterior slope, the angle of anterior slope, the angle of posterior slope weremeasured and the condylar volume was obtained. It was on the cross section that the maximum area of cross section, the intersection angle and the radialdistance from the condylar center point to the mid-sagittal plane weremeasured. It was on the cross section that the inner joint space, the medialjoint space and the outer joint space in the coronal plane of the maximummedialateral diameter were measured. It was on the cross section that theanterior joint space, the superior joint space and the posterior joint space in thesagittal plane of the perpendicular of the maximum medialateral diameter’smidpoint were measured. Each item was measured3times and the mean wastaken by the experimenter. Statistical software13.0was used to analysis. If thematerial were to the normal distribution, the mean and standard deviation wereused to describe the results. At first, paired-samples t test was used to judgewhether the symmetry of condylar morphology and location in mandibulardeviation patients. Then the differences of both sides of condyles between thedeviated and the normal groups were compared by using independent-samplest test. Inspection standard α=0.05.Results:1It was in the normal group that bilateral condyles did not show anydifference by using paired-samples t test (P>0.05). It was considered that thebilateral condyles were symmetry in morphology and location.2It was in the deviated group that bilateral condyles showed difference byusing paired-samples t test (P<0.05). It was suggested that the bilateralcondyles occurred to asymmetrical variation in morphology and location.2.1In the condylar morphology, the difference between the insilateral side(17.82±2.33mm) and the contralateral side (19.06±2.32mm) was statisticallysignificant in the medialateral diameter (P<0.05). The difference between theinsilateral side (20.33±2.98mm) and the contralateral side (22.22±3.33mm)was statistically significant in the perpendicular height (P<0.05). Thedifference between the insilateral side (5.51±0.55mm) and the contralateralside (6.02±0.49mm) was statistically significant in the length of anterior slope(P<0.05). The difference between the insilateral side (859.75±312.88mm3)and the contralateral side (937.65±314.90mm~3) was statistically significant in the volume (P<0.05). The difference between the insilateral side(109.67±25.07mm~2) and the contralateral side (120.36±25.49mm~2) wasstatistically significant in the area of maximum cross section (P<0.05).However, there were no statistical significances between the insilateral sideand the contralateral side in the anteroposterior diameter, the length ofposterior slope, the angle of anterior slope and the angle of posterior slope(P>0.05).2.2In the space location, condyles happened to rotate asymmetrically in theglenoid fossa. The difference between the insilateral side (2.81±0.59mm) andthe contralateral side (2.50±0.64mm) was statistically significant in the innerjoint space (P<0.05). The difference between the insilateral side (2.09±0.61mm) and the contralateral side (2.45±0.48mm) was statistically significant inthe outer joint space (P<0.05). The difference between the insilateral side(2.32±0.60mm) and the contralateral side (1.86±0.26mm) was statisticallysignificant in the anterior joint space (P<0.05). The difference between theinsilateral side (1.75±0.40mm) and the contralateral side (2.06±0.43mm) wasstatistically significant in the posterior joint space (P<0.05). However, therewere no statistical significances between the insilateral side and thecontralateral side in the intersection angle, the radial distance from thecondylar center point to the mid-sagittal line, the medial joint space and thesuperior joint space (P>0.05).3When the normal group was compared with the deviated group, it was foundthat the condyles of the deviated group occurred to asymmetrical variations inmorphology and location by using independent-samples t test.3.1In the condylar morphology, the difference between the deviated group(-1.24±0.91mm) and the normal group (0.08±0.48mm) was statisticallysignificant in the D-value of the medialateral diameter (P<0.05). Thedifference between the deviated group (-1.89±1.34mm) and the normal group(-0.32±1.41mm) was statistically significant in the D-value of theperpendicular height (P<0.05). The difference between the deviated group(-0.51±0.39mm) and the normal group (-0.01±0.42mm) was statistically significant in the D-value of the length of anterior slope (P<0.05). Thedifference between the deviated group (-77.90±51.37mm3) and the normalgroup (-2.75±9.38mm3) was statistically significant in the D-value of thevolume (P<0.05). The difference between the deviated group (-10.70±5.10mm~2) and the normal group (0.19±5.64mm~2) was statistically significant inthe D-value of the area of maximum cross section (P<0.05). However, therewere no statistical significances between the deviated group and the normalgroup in the D-value of the anteroposterior diameter, the D-value of the lengthof posterior slope, the D-value of the angle of anterior slope and the D-valueof the angle of posterior slope (P>0.05).3.2In the space location, condyles happened to rotate asymmetrically in theglenoid fossa. The difference between the deviated group (0.31±0.59mm) andthe normal group (-0.10±0.22mm) was statistically significant in the D-valueof the inner joint space (P<0.05). The difference between the deviated group(-0.37±0.48mm) and the normal group (0.13±0.44mm) was statisticallysignificant in the D-value of the outer joint space (P<0.05). The differencebetween the deviated group (0.46±0.48mm) and the normal group(-0.06±0.47mm) was statistically significant in the D-value of the anteriorjoint space (P<0.05). The difference between the deviated group (-0.32±0.63mm) and the normal group (0.13±0.40mm) was statistically significant in theD-value of the posterior joint space (P<0.05). However, there were nostatistical significances between the deviated group and the normal group inthe D-value of the intersection angle, the D-value of the radial distance fromthe condylar center point to the mid-sagittal line, the D-value of the medialjoint space and the D-value of the superior joint space (P>0.05).Conclusions: The patients with skeletal class mm~3of mandibular deviationwhose condyles occurred to asymmetry variations in morphology andlocation. |
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