Kim Kyung-A, Park Hong-Sik, Lee Soo-Yeon, Kim Su-Jung, Baek Seung-Hak, Ahn Hyo-Won
Department of Orthodontics, Kyung Hee University School of Dentistry, Seoul, Korea.
Department of Dentistry, Graduate School, Kyung Hee University, Seoul, Korea.
Korean J Orthod. 2019 Jul;49(4):254-264. doi: 10.4041/kjod.2019.49.4.254. Epub 2019 Jul 22.
To evaluate the short-term changes in masticatory muscle activity and mandibular movement patterns after orthognathic surgery in skeletal Class III patients with facial asymmetry.
Twenty-seven skeletal Class III adult patients were divided into two groups based on the degree of facial asymmetry: the experimental group (n = 17 [11 male and 6 female]; menton deviation ≥ 4 mm) and control group (n = 10 [4 male and 6 female]; menton deviation < 1.6 mm). Cephalography, electromyography (EMG) for the anterior temporalis (TA) and masseter muscles (MM), and mandibular movement (range of motion [ROM] and average chewing pattern [ACP]) were evaluated before (T0) and 7 to 8 months (T1) after the surgery.
There were no significant postoperative changes in the EMG potentials of the TA and MM in both groups, except in the anterior cotton roll biting test, in which the masticatory muscle activity had changed into an MM-dominant pattern postoperatively in both groups. In the experimental group, the amount of maximum opening, protrusion, and lateral excursion to the non-deviated side were significantly decreased. The turning point tended to be shorter and significantly moved medially during chewing in the non-deviated side in the experimental group.
In skeletal Class III patients with facial asymmetry, the EMG activity characteristics recovered to presurgical levels within 7 to 8 months after the surgery. Correction of the asymmetry caused limitation in jaw movement in terms of both ROM and ACP on the non-deviated side.
评估骨骼Ⅲ类面部不对称患者正颌手术后咀嚼肌活动和下颌运动模式的短期变化。
27例成年骨骼Ⅲ类患者根据面部不对称程度分为两组：实验组（n = 17 [男11例，女6例]；颏点偏斜≥4 mm）和对照组（n = 10 [男4例，女6例]；颏点偏斜<1.6 mm）。在手术前（T0）以及术后7至8个月（T1），对患者进行头影测量、颞肌前束（TA）和咬肌（MM）的肌电图（EMG）检查，以及下颌运动（运动范围[ROM]和平均咀嚼模式[ACP]）评估。
两组TA和MM的肌电图电位术后均无显著变化，但在前棉卷咬试验中，两组咀嚼肌活动术后均转变为以MM为主导的模式。在实验组中，最大开口度、前伸和向非偏斜侧的侧方运动幅度均显著降低。实验组非偏斜侧咀嚼时转折点往往更短且明显向内侧移动。
在骨骼Ⅲ类面部不对称患者中，肌电图活动特征在术后7至8个月内恢复到术前水平。不对称的矫正导致非偏斜侧在ROM和ACP方面的颌运动受限。
