Masseter myosin heavy chain composition varies with mandibular asymmetry.
Masseter myosin heavy chain composition varies with mandibular asymmetry.
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DOI：
10.1097/scs.0b013e3182107766
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发表时间：
2011-05
期刊：
影响因子：
--
通讯作者：
Ferri J
中科院分区：
文献类型：
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作者：
Raoul G;Rowlerson A;Sciote J;Codaccioni E;Stevens L;Maurage CA;Duhamel A;Ferri J
人类颌骨畸形很常见，经常影响年轻患者，导致牙齿咬合不正和颌骨关系不合适。根据需要通过正畸和正颌手术进行治疗。下颌不对称是最常见的畸形之一，但在许多情况下，具体原因尚不清楚。在接受正颌手术矫正咬合不正的健康患者中，我们测试了这样的假设：决定收缩特性的咬肌表型组成在下颌不对称患者的两侧不同，但在没有下颌不对称的患者中则没有。经过头影测量分析后，我们将 50 名获得左右咬肌样本的患者分为 2 组：有或没有下颌侧偏。使用肌球蛋白异构体特异性抗体对样本进行免疫染色，以识别 4 种骨骼肌纤维类型，并测量它们的纤维面积和比例。使用配对样品的双尾 Wilcoxon 检验通过两侧的占有率百分比和平均纤维面积来比较 4 种纤维类型的组合物。下颌不对称的患者与偏斜同侧的 II 型纤维占有率显着增加相关 (P = 0.0035)。咬肌表型与下颌不对称显着相关的这一发现与下颌差异的物理治疗和手术治疗相关，并且鉴于其在这种情况的病因学中可能发挥的作用，值得进一步研究。
Human jaw dysmorphologies are frequent and often affect young patients, resulting in malocclusion of teeth and inappropriate jaw relationships. Treatment is performed by means of orthodontics with orthognathic surgery as required. Mandibular asymmetry is one of the most frequent dysmorphologies, but in many cases, the specific cause is unknown. In healthy patients who were undergoing orthognathic surgery for correction of malocclusion, we tested the hypothesis that masseter muscle phenotype composition, which determines contractile properties, was different between sides in patients with mandibular asymmetry but not in those without mandibular asymmetry. After cephalometric analysis, 50 patients from whom we obtained samples of both right and left masseter muscles were separated into 2 groups: with or without mandibular lateral deviation. Samples were immunostained with myosin-isoform–specific antibodies to identify 4 skeletal muscle fiber types, and their fiber areas and proportions were measured. Two-tailed Wilcoxon test for paired samples was used to compare the 4 fiber-type compositions by means of percent occupancy and mean fiber area on both sides. Patients with mandibular asymmetry were associated with a significant increase of type II fiber occupancy (P = 0.0035) on the same side as the deviation. This finding that masseter muscle phenotype is significantly linked to mandibular asymmetry is of relevance to physiotherapeutic and surgical managements of jaw discrepancies and merits further investigation in the light of its possible role in the etiology of this condition.