Evaluation of stomatognathic functions through analysis of head movement : A new concept

在功能性和有节奏的下颌运动中，咀嚼和颈部肌肉的共同激活已经被证明。我们假设头部在活动时与下颌骨有节奏地协调运动。为了证明我们假设的有效性，我们检验了敲击过程中头部运动周期性的存在。选取健康成年男性，平均年龄25.5岁，闭塞正常，无TMD病史。我们利用光电测量系统，分别跟踪上切点和下切点，对头部和下颌骨的运动进行了三维测量。头部周期性地、有节奏地运动，就像下颌骨一样。上切点的运动方向与下颌骨相反。在打开过程中，头部向颅骨方向移动；关门时向尾端方向移动。头、下颌运动周期时间相关系数为0.94。头部的平均垂直运动范围为1.2(]SY.+- [)0.6mm，下颌骨的平均垂直运动范围为16.9(]SY.+- [)3.0mm。头部运动范围与下颌骨运动范围成正比，相关系数为0.74。从这些结果我们得出结论，在叩击过程中，头部运动与下颌骨运动功能协调。

The coactivation of mastication and neek muscles during functional and rhythmical mandibular movements has been demonstrated. We hypothesized that the head moves rhythmically and coordinately with the mandibule during function. To prove the validity of our hypothesis we examined the existence of periodicity of head movement during tapping. Healthy male adults, mean age 25.5, with normal occlusion and without TMD history were selected as subjects. Using photo-electrical measuring system, we measured tridimensionally both the movement of the head and mandible by tracking upper and lower incisal points respectively during tapping movements.The head moved periodical and rhythmically, as the mandible does. The upper incisal point moved in opposite direction to the mandible. During opening the head moved in a cranial direction ; during closing moved in a caudal direction. The cycle time of head and mandibular movements showed a correlation coefficient of o.94. The average vertical range of movement for the head was1.2(]SY.+-。[)0.6mm, and 16.9(]SY.+-。[)3.0mm for the mandible. The range of head movements were proportional to those of the mandible with a correlation cofficient of 0.74.From these results we conclude that during tapping the head moves in functional coordination with the mandible movement.