Dutra Eliane Hermes, Maruo Hiroshi, Vianna-Lara Michelle Santos
Pontifical Catholic University of Paraná, Curitiba, Brazil.
Am J Orthod Dentofacial Orthop. 2006 Jun;129(6):722.e1-9. doi: 10.1016/j.ajodo.2006.02.027.
The objective of this study was to evaluate and compare the electromyographic (EMG) activity of the orbicularis oris--lower fascicle (LOO) muscle and the mentalis muscle (MT)--in predominantly nose-breathing (PNB) and mouth-breathing (PMB) subjects.
Thirty-four subjects, 22 PNB and 12 PMB, with Class II Division 1 malocclusions were evaluated in 2001 (T1) and again in 2004 (T2), 2 years 5 months later. The age ranges of the sample were 11 years to 14 years 11 months at T1, and 13 years 4 months to 16 years 6 months at T2. EMG activity was recorded with bipolar surface electrodes at rest and during 12 movements; data were processed and normalized by the EMG highest value. The Student t test and the Mann-Whitney nonparametric test were used to compare the mean values and the variables between the observation times.
Greater EMG activity of the MT was observed in the PMB group at rest and swallowing at T1 and T2. At T2, increased EMG activity of the LOO at blowing and pronunciation of the phoneme \b\ was observed as well as a greater increment of EMG activity of this muscle at blowing, pronunciation of the phoneme \m, and chewing in the PMB group. In addition, greater EMG activity of the MT at chewing in the PMB group was observed at T2.
These results suggest that mouth breathing influences EMG activity of the LOO and MT muscles.
本研究的目的是评估和比较主要通过鼻腔呼吸（PNB）和口腔呼吸（PMB）的受试者口轮匝肌下部束（LOO）和颏肌（MT）的肌电图（EMG）活动。
2001年（T1）对34名患有安氏II类1分类错牙合畸形的受试者进行评估，其中22名PNB受试者和12名PMB受试者，2年零5个月后的2004年（T2）再次进行评估。样本在T1时的年龄范围为11岁至14岁11个月，在T2时为13岁4个月至16岁6个月。使用双极表面电极在静息状态和12种运动过程中记录EMG活动；数据通过EMG最高值进行处理和标准化。采用学生t检验和曼-惠特尼非参数检验比较观察时间之间的平均值和变量。
在T1和T2时，PMB组在静息和吞咽时观察到MT的EMG活动更强。在T2时，观察到PMB组在吹气和发\b\音时LOO的EMG活动增加，以及该肌肉在吹气、发\m\音和咀嚼时EMG活动的更大增量。此外，在T2时观察到PMB组在咀嚼时MT的EMG活动更强。
这些结果表明口腔呼吸会影响LOO和MT肌肉的EMG活动。
