de Brito Bitencourt Greice, Gonçalves Marcela Leticia Leal, Kobayashi Fernanda Yukie, Motta Lara Jansiski, Silva Daniela Fátima Teixeira da, Politti Fabiano, Paulino Feliciano Leandro, Mesquita-Ferrari Raquel Agnelli, Fernandes Kristianne Porta Santos, Bussadori Sandra Kalil
Universidade Nove de Julho, Liberdade, São Paulo, Brazil.
Medicine (Baltimore). 2018 Jun;97(26):e11340. doi: 10.1097/MD.0000000000011340.
Orofacial pain encompasses painful conditions, such as temporomandibular disorder (TMD). Multidisciplinary health teams seek to control such musculoskeletal disorders to improve the quality and functional capacity of the muscles of mastication. The aim of the proposed study is to evaluate the effect of low-level laser therapy as a form of treatment for the prevention of initial fatigue of the muscles of mastication (masseter and anterior temporal muscles) as well as the recovery of these muscles after induced exhaustion (caused by isometric contraction) in young adults.
The participants will be 78 healthy male and female volunteers between 18 and 34 years of age. The volunteers will be randomly allocated to a laser group (n = 26), sham group (n = 26), and control group (n = 26). All participants will be submitted to a clinical evaluation to record mandibular movements, bite force, muscle sensitivity to palpation, and initial muscle fatigue. Initial fatigue will be induced by isometric contraction of the jaws. Maximum voluntary contraction will be performed to record the time until initial exhaustion of the masseter muscle (determined by electromyography). The groups will then be submitted to the interventions: active laser therapy (wavelength: 780 nm; fluence: 134 J/cm; power: 50 mW; irradiance: 1.675 W/cm; exposure time: 80 seconds per point) on 3 points of the masseter and 1 point on the anterior temporal muscles on each side; sham laser (placebo effect); or no intervention (control). Maximum voluntary contraction will be performed again after the interventions to record the time until initial exhaustion of the masseter muscle (determined by electromyography). Differences in individual time until exhaustion between the pre- and postintervention evaluations will be measured to determine the effect of low-level laser therapy.
Although studies have been made with the use of low-level laser therapy in TMDs and on the effect of photobiomodulation on fatigue, this the first study to test this therapy in the prevention of fatigue in this region. The clinical relevance lies in the fact that longer dental procedures could take place if the patients are less prone to fatigue.
口面部疼痛包括诸如颞下颌关节紊乱病（TMD）等疼痛病症。多学科健康团队致力于控制此类肌肉骨骼疾病，以提高咀嚼肌的质量和功能能力。本拟研究的目的是评估低强度激光疗法作为一种治疗形式，对预防年轻成年人咀嚼肌（咬肌和颞肌前部）初始疲劳以及诱导疲劳（由等长收缩引起）后这些肌肉恢复的效果。
参与者将为78名年龄在18至34岁之间的健康男性和女性志愿者。志愿者将被随机分配到激光组（n = 26）、假治疗组（n = 26）和对照组（n = 26）。所有参与者都将接受临床评估，以记录下颌运动、咬合力、肌肉触诊敏感性和初始肌肉疲劳情况。初始疲劳将通过颌部等长收缩诱导产生。将进行最大自主收缩以记录咬肌直至初始疲劳的时间（通过肌电图确定）。然后各小组将接受干预：对每侧咬肌的3个点和颞肌前部的1个点进行主动激光治疗（波长：780 nm；能量密度：134 J/cm²；功率：50 mW；辐照度：1.675 W/cm²；每个点的照射时间：80秒）；假激光治疗（安慰剂效应）；或不进行干预（对照）。干预后将再次进行最大自主收缩，以记录咬肌直至初始疲劳的时间（通过肌电图确定）。测量干预前后个体直至疲劳的时间差异，以确定低强度激光疗法的效果。
尽管已经有关于在颞下颌关节紊乱病中使用低强度激光疗法以及光生物调节对疲劳影响的研究，但这是第一项测试该疗法预防该区域疲劳效果的研究。临床意义在于，如果患者不易疲劳，那么牙科手术时间可以延长。
