Takeuchi Hisahiro, Bando Eiichi, Abe Susumu
Department of General Dentistry, Tokushima University Medical and Dental Hospital.
Nihon Hotetsu Shika Gakkai Zasshi. 2008 Jul;52(3):311-20. doi: 10.2186/jjps.52.311.
To establish standardized evaluating methods for jaw movements analysis independently of the reference coordinate system. In this paper, we focused on the analysis of incisor point paths of border movements. Then we investigated parameters that are independent of the reference coordinate system and can be utilized among different systems.
Recorded data of jaw border movements from 20 healthy male adults were employed as basic samples. First, the effects of changes of the reference coordinate systems on the analysis were investigated. Second, the line between incisor points at the intercuspal position and the maximal mandibular opening position was used as the reference line. Then the area index of incisor paths was calculated with the length of the perpendicular line dropped from the incisor point to the reference line and the displacement of the foot of the perpendicular.
Changes of the spatial relation between a reference plane of the coordinate system and border movements pathways had an effect on a measured area of projected pathways, about 2% - 5% differences of projected area on the frontal plane with 10 degrees rotation around a horizontal axis. The area index of incisor paths showed close correlation with the actual area of a 3-dimensional plane bounded by the incisor path [sagittal border movement: r = 0.53 (p = 0.016), left border opening pathway: r = 0.97 (p < 0.001), right border opening pathway: r = 0.98 (p < 0.001), Spearman rank correlation].
The results suggest that new parameters could measure jaw border movements quantitatively independent of the reference coordinate system.
建立独立于参考坐标系的颌运动分析标准化评估方法。在本文中，我们重点分析边缘运动的切牙点轨迹。然后，我们研究了独立于参考坐标系且可在不同系统中使用的参数。
将20名健康成年男性的颌边缘运动记录数据作为基础样本。首先，研究参考坐标系变化对分析的影响。其次，将牙尖交错位与下颌最大开口位时切牙点之间的连线作为参考线。然后，根据从切牙点到参考线的垂直线长度和垂足的位移计算切牙轨迹的面积指数。
坐标系参考平面与边缘运动路径之间空间关系的变化对投影路径的测量面积有影响，绕水平轴旋转10度时，额平面上投影面积的差异约为2% - 5%。切牙轨迹的面积指数与由切牙轨迹界定的三维平面的实际面积密切相关[矢状边缘运动：r = 0.53（p = 0.016），左侧边缘开口路径：r = 0.97（p < 0.001），右侧边缘开口路径：r = 0.98（p < 0.001），Spearman等级相关性]。
结果表明，新参数可以独立于参考坐标系定量测量颌边缘运动。
