背景:A型肉毒杆菌毒素会导致肌肉麻痹,并广泛用于咀嚼肌治疗口颌疾病,比如颞下颌关节紊乱病,磨牙症,或者咬肌肥大。尽管如此,其肌肉效应尚不清楚。更好的理解可以帮助改善使用,也许还有新的适应症,特别是在颌面骨科和正颌外科。
方法:本系统综述探讨了肉毒杆菌毒素对动物和人类咀嚼肌的组织学和功能影响,并按照系统评价和荟萃分析的首选报告项目的建议进行。MEDLINE,WebofScience,并在Cochrane图书馆电子数据库中检索相关文章。纳入标准是肉毒杆菌毒素注射后的人或动物咀嚼肌分析和通过光学或电子显微镜的组织学结构/超微结构分析,或通过咬合力评估(咬合力分析仪)和肌肉活动(肌电图)的功能效应分析。
结果:在最初的1578篇文章中,最终纳入了44项研究。在咀嚼肌中注射肉毒杆菌毒素改变了其组织学结构和功能特性。人类和动物研究揭示了超微结构的变化,萎缩,和一次注射后咀嚼肌的纤维类型修饰。肉毒杆菌毒素降低咬合力和肌肉活动,但复苏是不确定的。
结论:施加在骨骼上的肌肉力量是面部生长的关键特征。咀嚼性肌肉麻痹改变骨骼上的机械应力,重新平衡施加在面部骨骼上的力。这种新的平衡可能有益于牙齿畸形或手术复发。因此,肉毒杆菌毒素可能会限制这些患者咀嚼肌的正颌作用。鉴于复苏的不确定性,应避免多次注射,用法不应偏离既定共识。
BACKGROUND: Botulinum toxin type A causes muscle paralysis and is widely used in the masticatory muscle for stomatognathic diseases, such as temporomandibular disorder, bruxism, or masseteric hypertrophy. Nonetheless, its muscular effect remains unclear. Better understanding could aid improved use and perhaps new indications, particularly in dentofacial orthopaedics and orthognathic surgery.
METHODS: This systematic review explored the histologic and functional effects of botulinum toxin in animal and human masticatory muscles and was conducted in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The MEDLINE, Web of Science, and Cochrane Library electronic databases were searched for relevant articles. The inclusion criteria were human or animal masticatory muscle analysis after botulinum toxin injection(s) AND histological structural/ultrastructural analysis by optical or electronic microscopy OR functional effect analysis by bite force evaluation (occlusal force analyzer) and muscle activity (electromyography).
RESULTS: Of an initial 1578 articles, 44 studies were eventually included. Botulinum toxin injection in the masticatory muscle altered its histological structure and functional properties. The human and animal studies revealed ultrastructural change, atrophy, and fiber type modifications of the masticatory muscles after one injection. Botulinum toxin decreased bite force and muscle activity, but recovery was uncertain.
CONCLUSIONS: Muscle forces applied on the skeleton is a key feature of facial growth. Masticatory muscle paralysis changes mechanical stress on bones, which rebalances the force applied on facial bones. This new balance could benefit dental deformity or surgical relapse. Therefore, botulinum toxin could limit the orthognathic effect of the masticatory muscles in such patients. Given the uncertain recovery, multiple injections should be avoided, and usage should not deviate from established consensus.