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Abstract
Introduction
To correct the facial asymmetry by mandibular jaw surgery, it is important to know the anatomy of the mandible including the mandibular canal positioning of patients with facial asymmetry. This study was performed to evaluate the differences in the cross-sectional surface in the body of the mandible between the deviated side and opposite side in patients with facial asymmetry.
Materials and Methods
The study was conducted on 37 adult patients composed of 2 groups, the asymmetry group (n=20) and non-asymmetry group (n=17). Using the cross-sectional computed tomography (CT) images, the distance from the buccal aspect of the mandibular canal to the outer aspect of the buccal cortex, distance from the buccal aspect of the mandibular canal to the inner aspect of the buccal cortex, distance from the inferior aspect of the mandibular canal to the inferior border of the mandible, thickness of the mandible, and cross-sectional surface area of the mandible were measured in each side of the mandible.
Results
The cross-sectional area of the mandible including the mandibular canal positioning in the deviated side was not statistically different from the opposite side in the asymmetry group. Only the distance from the inferior aspect of the mandibular canal to the inferior border of the mandible in the ramus area of the deviated side was significantly longer than opposite side. On the other hand, the buccolingual width of the asymmetry group was thinner than the non-asymmetry group.
References
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Fig. 1.
Converted images by using Ondemand program. A: Axial image, B: Cross-sectional image, C: Panoramic image.
Fig. 2.
Measuring points and measurements in the cross sectional images. (A: distance from the buccal aspect of the mandibular canal to outer aspect of the buccal cortex, B: distance from the buccal aspect of the mandibular canal to inner aspect of the buccal cortex, C: distance from the inferior aspect of the mandibular canal to inferior border of the mandible, D: thickness of the mandible, E: cross-sectional surface area of the mandible)
Table 1.
Patients distribution
| Group | Male/Female | Mean age | Chin deviation |
|---|---|---|---|
| Non-asymmetry (n=17) | 9/8 | 23.7±4.28 | |
| Asymmetry (n=20) | 7/13 | 22.6±3.55 | 6.2±2.9 (Rt./Lt.=8/12) |
Table 2.
Measurements in the asymmetry group
| Deviated side | Opposite side | P value | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 1st molar | 2nd molar | Ramus | 1st molar | 2nd molar | Ramus | 1st molar | 2nd molar | Ramus | |
| A | 4.68±1.87 | 6.36±1.47 | 4.88±1.36 | 5.09±1.76 | 6.24±1.56 | 4.68±1.30 | 0.155 | 0.687 | 0.497 |
| B | 2.33±1.48 | 3.87±1.55 | 2.56±1.29 | 2.54±1.27 | 3.55±1.57 | 2.40±1.19 | 0.448 | 0.264 | 0.58 |
| C | 8.81±3.19 | 8.18±1.94 | 10.30±3.36 | 8.48±2.97 | 8.17±1.85 | 11.51±4.00 | 0.503 | 0.822 | 0.033* |
| D | 10.78±2.76 | 12.87±1.87 | 11.38±2.17 | 11.12±1.56 | 12.70±1.80 | 11.10±1.78 | 0.513 | 0.477 | 0.361 |
| E | 331.18±48.62 | 364.70±78.99 | 374.27±90.36 | 332.94±57.72 | 353.74±84.80 | 368.67±79.05 | 0.762 | 0.335 | 0.49 |
A: distance from the buccal aspect of the mandibular canal to outer aspect of the buccal cortex, B: distance from the buccal aspect of the mandibular canal to inner aspect of the buccal cortex, C: distance from the inferior aspect of the mandibular canal to inferior border of the mandible, D: thickness of the mandible, E: cross-sectional surface area of the mandible)
Table 3.
Measurements in the normal occlusion group
(A: distance from the buccal aspect of the mandibular canal to outer aspect of the buccal cortex, B: distance from the buccal aspect of the mandibular canal to inner aspect of the buccal cortex, C: distance from the inferior aspect of the mandibular canal to inferior border of the mandible, D: thickness of the mandible, E: cross-sectional surface area of the mandible)
Table 4.
Comparison of the measurements according to group
| 1st molar | 2nd molar | Ramus | |
|---|---|---|---|
| A | 0.171 | 0.054 | 0.151 |
| B | 0.046* | 0.013* | 0.089 |
| C | 0.724 | 0.569 | |
| D | 0.009** | 0.019* | 0.031* |
| E | 0.013* | 0.019* | 0.010* |
A: distance from the buccal aspect of the mandibular canal to outer aspect of the buccal cortex, B: distance from the buccal aspect of the mandibular canal to inner aspect of the buccal cortex, C: distance from the inferior aspect of the mandibular canal to inferior border of the mandible, D: thickness of the mandible, E: cross-sectional surface area of the mandible)
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