安氏Ⅰ、Ⅱ、Ⅲ类错(牙合)患者机械耳点与解剖耳点的位置关系的对比研究

目的　研究安氏Ⅰ、Ⅱ、Ⅲ类错牙合患者头颅侧位定位片上机械耳点与解剖耳点的相对位置关系,探讨两点之间的位置关系是否与错牙合类型有关。方法　选择恒牙列错牙合畸形患者6 5 0例,其中安氏Ⅰ类错牙合2 6 8例,安氏Ⅱ类错牙合2 2 3例,安氏Ⅲ类错牙合15 9例。以头颅侧位定位片上机械耳点最上缘为原点,以FH平面为x轴,建立直角坐标系,测量3种错牙合畸形的解剖耳点与机械耳点的相对位置关系。结果　不同类型错牙合畸形患者的机械耳点与解剖耳点的位置关系无显著性差别。机械耳点与解剖耳点的相对位置关系有4种表现形式。两点的不重叠率高达79 .9%。结论　机械耳点与解剖耳点常不重叠的现象是由外耳道的解剖结构所决定的,与错牙合畸形的类型无关。

The Study of Location Relationship of Mechanical Porion and Anatomical Porion in Different Angle's Malocclusions

Objective To study the location relationship of mechanical Porion(Po-m) and anatomical Porion(Po-a) in different Angle's malocclusions. Methods 650 cephalometric films with different Angle's malocclusions, were respectively selected. Right-angled reference frame was built with the upside of Po-m as origin and FH plane as x-axis in order to measure the location relationship of Po-m and Po-a. Results The location relationship of Po-m and Po-a showed no significant difference between different Angle class malocclusion. There were four kinds of location relationships between Po-m and Po-a, and the inconsistency rate is 79.9%. Conclusion The different location of Po-m and Po-a was determined by the anatomical structure of outer earhole but not malocclusion.