Food textural study by mastication pressure, palatal pressure and electromyography

在进食过程中同步测量咀嚼肌电(EMG)和第一磨牙上的压力，以及上颌三点上的压力。采用表面肌电极法测定左、上咬肌和颞肌的肌电。咀嚼压力是通过嵌入到人工第一磨牙中的压力传感器来检测的，人工第一磨牙是为了替换丢失的天然牙而安装的。以1%~7%的明胶凝胶、精制奶酪、萝卜、杏仁、塔冠等不同质地的食物为测试样本，通过第一次咀嚼获得与食物质地有关的咀嚼压力和肌电的最大特征模式，对应于被吃食物的第一次变形。第一次咬合时，咀嚼压力的积分与肌电幅值的积分有很好的相关性，即咀嚼压力所做的功与咀嚼肌的活动有关。然后，信号模式变得相似，而不是取决于食物的质地。随着咀嚼的进行。最大肌电电压还与第一次咀嚼时的最大咀嚼压力有关，可以借助肌电推导出食物上的最大咀嚼压力的近似值。对于凝胶，可以用舌头和上颌压力咀嚼，呈现出一种无节奏的、相对连续的模式。随着凝胶稠度变得更硬，肌电增加，并呈现节律性模式，而腭压没有增加。肌电从连续到有节奏的变化表明，随着凝胶密度的增加，与舌头和上颚咀嚼的凝胶的密度改变为与牙齿的咀嚼凝胶的密度。

Mastication electromyograms (EMG) and the pressure on a first molar tooth, as well as the pressure on three points of the palate were synchronously measured during eating. EMG of the left and hight masseter and temporalis muscles were measured with surface electrodes. The mastication pressure was detected by a pressure transducer embedded in an artificial first molar tooth that had been fitted to replace a lost natural tooth. The palatal pressure was also detected by pressure transducers embedded in the palatal retainer surface on the tongue side.Foods with various texture' e. g., 1 to 7% of gelatin gels, processed cheese, radish, almond and takuan were used as test samples.The most characteristic patterns depending on food texture for both the mastication pressure and EMG were obtained with the first bite, corresponding to the first deformation of the food eaten. The integral of the mastication pressure correlated well with that cf the EMG amplitude for the first bite ; i. e., the work done by mastication pressure was related to the activity of the masticatory muscles. The signal patterns then became similar, not depending on the food texture. as mastication proceeded. The maximum EMG voltage was also related to the maximum mastication pressure with the first bite, it being possible to deduce an approximate value for the maximum mastication pressure on the food with the aid of EMG.EMG for gel, which could be masticated by the tongue and palatal pressure, showed a non-rhythmic, relatively continuous pattem. As the gel consistency become harder, EMG increased and showed a rhythmic pattem in contrast to no increment in the palatal pressure. The change in EMG from a continuous to rhythmic pattem shows the density of the gels at which mastiction with the tongue and palate changes to that with the teeth, as the density of the gel increased.