Department of Oral and Maxillofacial Surgery, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510150, China.
Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, NO.39 Huangsha Avenue, Guangzhou, 510150, China.
Aesthetic Plast Surg. 2024 Oct;48(19):3751-3757. doi: 10.1007/s00266-024-04309-2. Epub 2024 Aug 26.
The aim of this study was to quantitatively evaluate morphological and volumetric changes in the masseter muscle using 3-dimensional analysis of facial asymmetry patients and to identify factors influencing these changes before and after orthognathic surgery.
[Reviewer1 (2)]A single-center retrospective cohort study was conducted on twenty-two patients with deviation of the chin > 4 mm. Masseter muscle volume and morphology were measured at different periods during long-term follow-up (mean 15 ± 3.2 months). Factors related to changes in masseter muscle cross-sectional area and volume analyzed were also analyzed.
[Reviewer1 (2) and (9)]The volume and cross-sectional area of the masseter muscle on the non-deviated side reduced by 13.5% (P < 0.05) and 16.4% (P < 0.05), respectively, after orthognathic surgery. The length of the masseter muscle increased by 13.9% on the deviated side (P < .05) but decreased by 11.7% on the non-deviated side (P < 0.05). The width decreased on the deviated side from T1 to T2 (13.51 ± 2.09 mm vs. 12.04 ± 1.39 mm), but the non-deviated side showed an opposite tendency (10.81 ± 1.31 mm vs. 12.69 ± 2.37 mm). The difference in masseter muscle length and width between the two sides significantly reduced after surgery (P < 0.05). There was a noticeable decrease in the asymmetry in the muscle in proportion to the degree of the occlusal plane angle.
Masseter muscle asymmetry exists in patients with facial asymmetry, but it could be improved with maxilla-mandible correction. Atrophy of the masseter muscle after orthognathic surgery was greater in patients with a large inclined occlusal plane angle due to improved dental compensation.
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本研究旨在通过三维分析面部不对称患者，定量评估咀嚼肌的形态和体积变化，并确定影响正颌手术后这些变化的因素。
对 22 例颏偏距>4mm 的患者进行单中心回顾性队列研究。在长期随访（平均 15±3.2 个月）的不同时期测量咀嚼肌体积和形态。还分析了与咀嚼肌横截面积和体积变化相关的因素。
正颌手术后，非偏侧咀嚼肌的体积和横截面积分别减少了 13.5%（P<0.05）和 16.4%（P<0.05）。偏侧咀嚼肌的长度增加了 13.9%（P<0.05），而非偏侧咀嚼肌的长度减少了 11.7%（P<0.05）。从 T1 到 T2，偏侧咀嚼肌的宽度减小（13.51±2.09mm 比 12.04±1.39mm），而非偏侧咀嚼肌的宽度呈相反趋势（10.81±1.31mm 比 12.69±2.37mm）。手术后两侧咀嚼肌长度和宽度的差异显著减小（P<0.05）。随着咬合平面角的程度增加，肌肉的不对称性明显减小。
面部不对称患者存在咀嚼肌不对称，但通过上颌-下颌矫正可以改善。正颌手术后，由于牙齿补偿的改善，咬合平面角较大的患者咀嚼肌萎缩更为明显。
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