LOADING PATTERNS AND JAW MOVEMENTS DURING MASTICATION IN MACACA-FASCICULARIS - A BONE-STRAIN, ELECTROMYOGRAPHIC, AND CINERADIOGRAPHIC ANALYSIS
LOADING PATTERNS AND JAW MOVEMENTS DURING MASTICATION IN MACACA-FASCICULARIS - A BONE-STRAIN, ELECTROMYOGRAPHIC, AND CINERADIOGRAPHIC ANALYSIS
复制标题
DOI：
10.1002/ajpa.1330720304
复制
发表时间：
1987-03-01
影响因子：
2.8
通讯作者：
CROMPTON, AW
中科院分区：
文献类型：
--
作者：
HYLANDER, WL;JOHNSON, KR;CROMPTON, AW
使用花环应变计、肌电图 (EMG) 和电影放射摄影技术来分析束状猕猴咀嚼过程中的负载模式和下颌运动。电影放射线数据表明，猕猴通常在整个咀嚼过程中频繁吞咽，并且这些吞咽会在动力冲程结束时插入咀嚼周期。骨应变和颌运动数据表明，在剧烈咀嚼过程中，快速闭合和动力冲程之间的过渡与咀嚼力的急剧增加相关，并且它们还表明，在大多数情况下，猕猴的颌在最大牙尖交错之前，即在第一阶段（颊期）咬合运动期间，承受最大负荷。此外，这些数据表明第二阶段（舌期）咬合运动期间的负荷通常相对较小。骨应变数据还表明，咀嚼动力冲程期间颌部卸载的持续时间很大程度上是颌内收肌松弛时间的函数。这一解释基于以下发现：卸载过程中从 100% 峰值应变到 50% 峰值应变的持续时间非常接近猕猴整个内收颌肌的半松弛时间。咬肌和内侧翼状肌的肌电图数据对于理解动力冲程的生物力学和负责咀嚼动力冲程期间沿下颌联合和体发生“叉骨”效应的外力具有重要意义。尽管两个内侧翼状肌在动力冲程期间都达到最大肌电图活动，但工作侧内侧翼状肌的活动在平衡侧内侧翼状肌之后达到峰值。与工作侧翼状肌内侧力量的同时增加和平衡侧翼状肌内侧力量的减少相关的是平衡侧深层咬肌（后部）持续高水平的肌电图活动。这种模式具有相当重要的意义，因为工作侧翼状肌内侧和平衡侧深层咬肌的作用力方向都很好地对齐，有助于在单侧咀嚼过程中沿内侧方向驱动工作侧下臼齿穿过上臼齿。此外，平衡侧深层咬肌的持续活动与剩余平衡侧肌肉的逐渐松弛相关，表明虽然沿平衡侧的垂直力正在减小，但横向力相对增加，这导致在整个动力冲程中平衡侧下颌体和联合（叉骨）的侧向横向弯曲增加。
Rosette strain gage, electromyography (EMG), and cineradiographic techniques were used to analyze loading patterns and jaw movements during mastication in Macaca fascicularis. The cineradiographic data indicate that macaques generally swallow frequently throughout a chewing sequence, and these swallows are intercalated into a chewing cycle towards the end of a power stroke. The bone strain and jaw movement data indicate that during vigorous mastication the transition between fast close and the power stroke is correlated with a sharp increase in masticatory force, and they also show that in most instances the jaws of macaques are maximally loaded prior to maximum intercuspation, i.e. during phase I (buccal phase) occlusal movements. Moreover, these data indicate that loads during phase II (lingual phase) occlusal movements are ordinarily relatively small. The bone strain data also suggest that the duration of unloading of the jaw during the power stroke of mastication is largely a function of the relaxation time of the jaw adductors. This interpretation is based on the finding that the duration from 100% peak strain to 50% peak strain during unloading closely approximates the half-relaxation time of whole adductor jaw muscles of macaques. The EMG data of the masseter and medial pterygoid muscles have important implications for understanding both the biomechanics of the power stroke and the external forces responsible for the "wishboning" effect that takes place along the mandibular symphysis and corpus during the power stroke of mastication. Although both medial pterygoid muscles reach maximum EMG activity during the power stroke, the activity of the working-side medial pterygoid peaks after the balancing-side medial pyterygoid. Associated with the simultaneous increase of force of the working-side medial pterygoid and the decrease of force of the balancing-side medial pterygoid is the persistently high level of EMG activity of the balancing-side deep masseter (posterior portion). This pattern is of considerable significance because the direction of force of both the working-side medial pterygoid and the balancing-side deep masseter are well aligned to aid in driving the working-side lower molars across the upper molars in the medial direction during unilateral mastication. Moreover, the persistent activity of the balancing-side deep masseter associated with the gradual relaxation of the remaining balancing-side muscles indicates that although vertical force along the balancing side is decreasing, there is a relative increase in laterally directed force, and this results in an increase in lateral transverse bending of the balancing-side mandibular corpus and symphysis (wishboning) throughout the power stroke.