Cha Bong Kuen, Kim Chun-Hi, Baek Seung-Hak
College of Dentistry, Department of Orthodontics, Kangnung National University, Kangnung, Kangwondo, South Korea.
Angle Orthod. 2007 May;77(3):463-70. doi: 10.2319/0003-3219(2007)077[0463:SSAVFT]2.0.CO;2.
To investigate the electromyographic activities of the anterior temporal (T) and masseter (M) muscles in different facial skeletal types.
The samples consisted of 105 subjects (38 males and 67 females; mean age 22.0 +/- 6.7 years) and were classified into six groups according to the values of ANB and SN-GoMe: group 1 for Class I malocclusion and normodivergent type (n = 27), group 2 for Class I and hyperdivergent type (n = 20), group 3 for Class II and normodivergent type (n = 10), group 4 for Class II and hyperdivergent type (n = 23), group 5 for Class III and normodivergent type (n = 12), and group 6 for Class III and hyperdivergent type (n = 13). Temporal muscle activity (TMA), masseter muscle activity (MMA), and T/M ratio were evaluated at resting and clenching status.
Although there was no significant difference in resting MMA among all groups, group 6 showed a higher resting TMA than did other groups and a significant difference in resting T/M ratio compared with groups 1 and 3. There were no significant differences in clenching TMA and MMA among all groups. Although all groups showed a significant increase of TMA and MMA from resting to clenching status, group 6 showed a significant decrease of clenching T/M ratio compared with resting T/M ratio.
The results suggest that the more Class III and the more hyperdivergent type, the higher resting TMA and the lesser increase of clenching MMA than expressed by other groups. Significant differences existed in TMA and MMA according to sagittal and vertical facial skeletal types.
研究不同面部骨骼类型中颞肌前束（T）和咬肌（M）的肌电活动。
样本包括105名受试者（38名男性和67名女性；平均年龄22.0±6.7岁），根据ANB和SN-GoMe值分为六组：1组为安氏I类错牙合且均角型（n = 27），2组为安氏I类且高角型（n = 20），3组为安氏II类且均角型（n = 10），4组为安氏II类且高角型（n = 23），5组为安氏III类且均角型（n = 12），6组为安氏III类且高角型（n = 13）。在静息和紧咬状态下评估颞肌活动（TMA）、咬肌活动（MMA）以及T/M比值。
尽管所有组静息时的MMA无显著差异，但6组静息时的TMA高于其他组，且静息时的T/M比值与1组和3组相比有显著差异。所有组紧咬时的TMA和MMA无显著差异。尽管所有组从静息到紧咬状态时TMA和MMA均显著增加，但6组紧咬时的T/M比值与静息时相比显著降低。
结果表明，安氏III类错牙合且高角型程度越高，静息时的TMA越高，紧咬时MMA的增加幅度小于其他组。根据矢状向和垂直向面部骨骼类型，TMA和MMA存在显著差异。
