Takada K, Miyawaki S, Tatsuta M
Department of Orthodontics, Faculty of Dentistry, Osaka University, Japan.
Arch Oral Biol. 1994 Sep;39(9):793-805. doi: 10.1016/0003-9969(94)90009-4.
The possible effects of food consistency on the number of chews and the lapse of time in a chewing sequence, the jaw-movement pattern and velocity, and jaw and lip muscle activity during chewing were investigated. Fifteen healthy children with good occlusion were selected. First, each subject freely chewed hard (HJ) and soft (SJ) types of jelly without specifying the chewing side. The number of chews and elapsed time in a masticatory sequence (from the start of chewing to the completion of the final swallow) were measured. Second, the subjects performed right- and left-sided chewing of the same food. The electromyograms (EMG) of posterior temporalis (PT) and inferior orbicularis oris (OI) muscles on the right and left sides and associated jaw movement records were sampled. The HJ was chewed more times and with a longer time until finally swallowed (p < or = 0.0007) than the SJ. The HJ chewing also showed broader masticatory loops (p < or = 0.0199) in the frontal view and higher peak activities (p < or = 0.0007) for the PT muscle. The closing phase was longer when chewing the HJ than SJ, but the opening and intercuspal phases remained stable. More lateral excursion of the jaw was seen when chewing the HJ, but the jaw-movement trajectories in the sagittal and vertical directions were not affected by the change in consistency of the food. The jaw-closing velocities for the HJ chews were significantly slower (p < or = 0.0351) than those for the SJ chews in three directions. The HJ chews also revealed a longer duration between the onset of EMG burst for the PT muscle and the beginning of the centric occlusion (p < or = 0.0146). The OI muscle showed increased activity in accord with jaw opening, and consistent reciprocal cyclic activity with the PT muscle in terms of temporal associations (r > or = 0.5250; p < or = 0.0495). The OI muscle started to burst at a later part of the intercuspal phase, and frequently showed secondary activity in the jaw-closing and intercuspal phases. The peak activity for the ipsilateral OI muscle was significantly higher (p < or = 0.0106) than that for the contralateral OI muscle for both the HJ and SJ. The OI muscle activity, however, did not differ between the hard and soft jellies.(ABSTRACT TRUNCATED AT 400 WORDS)
研究了食物质地对咀嚼次数、咀嚼序列中时间流逝、咀嚼时的下颌运动模式和速度以及下颌和唇部肌肉活动的可能影响。选取了15名咬合良好的健康儿童。首先，让每个受试者自由咀嚼硬质地（HJ）和软质地（SJ）的果冻，不指定咀嚼侧。测量咀嚼序列（从开始咀嚼到最终吞咽完成）中的咀嚼次数和经过时间。其次，受试者对同一种食物进行右侧和左侧咀嚼。采集左右侧颞肌后部（PT）和口轮匝肌下部（OI）的肌电图（EMG）以及相关的下颌运动记录。与SJ相比，HJ咀嚼次数更多，直到最终吞咽的时间更长（p≤0.0007）。HJ咀嚼在额面也显示出更宽的咀嚼环（p≤0.0199），PT肌肉的峰值活动更高（p≤0.0007）。咀嚼HJ时的闭口期比SJ长，但开口期和牙尖交错期保持稳定。咀嚼HJ时下颌的侧向偏移更多，但食物质地变化对下颌在矢状和垂直方向的运动轨迹没有影响。HJ咀嚼在三个方向上的下颌闭合速度明显慢于SJ咀嚼（p≤0.0351）。HJ咀嚼还显示PT肌肉肌电爆发开始与正中咬合开始之间的持续时间更长（p≤0.0146）。OI肌肉随着下颌张开活动增加，在时间关联方面与PT肌肉有一致的相互循环活动（r≥0.5250；p≤0.0495）。OI肌肉在牙尖交错期的后期开始爆发，在闭口期和牙尖交错期经常出现二次活动。HJ和SJ时同侧OI肌肉的峰值活动均显著高于对侧OI肌肉（p≤0.0106）。然而，硬质地和软质果冻之间的OI肌肉活动没有差异。（摘要截断于400字）
