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在自然头位下拍摄头颅侧位片进行头影测量分析是长期稳定的,本研究首次为这一结论提供了依据。样本为20名居住在香港的中国人,其中10名男性,10名女性,他们在12岁时拍摄了初始的自然头位X线头颅侧位片,15年后又重复拍摄了自然头位X线头颅侧位片。本研究以蝶鞍点-鼻根点连线与真性垂直线所形成的角(SN/Vert)评价自然头位的可重复性。自然头位可重复性以方法误差(method error,ME)表示,ME=√∑d~2/2n。研究结果显示15年后方法误差是2.2°,方差(ME~2)是4.8°(2.2~2)。而以往常规采用的解剖头位的颅内参考平面,如前颅底平面(SN),与真性垂直线所形成的角的标准差是5°～6°,方差(SD~2)是25°～36°。自然头位的方差显著较小。很显然,即使在15年后自然头位也是进行头影测量分析的一个稳定参考位。因此自然头位下拍摄头颅侧位片进行头影测量分析是可
The cephalometric analysis of the cephalometric slices under the natural head position is long-term and stable. This study provides the basis for this conclusion for the first time. The sample was 20 Chinese living in Hong Kong, of whom 10 were males and 10 females. At the age of 12, they photographed the initial natural head X-ray cephalograms. After 15 years, the natural head X Line head skull slice. In this study, the natural head position repeatability was evaluated by the angle (SN / Vert) formed by the saddle point-nose root line and the true vertical line. Natural head repeatability is expressed as a method error (ME), ME = √Σd ~ 2 / 2n. The results show that after 15 years the method error is 2.2 ° and the variance (ME ~ 2) is 4.8 ° (2.2 ~ 2). Whereas the standard deviation of the angle formed by the vertical lines of the true anastomosis is 5 ° ~ 6 ° and the standard deviation of SD ~ 2 is 25 ° ~ 36 °. The variance of natural head position is significantly smaller. Obviously, even after 15 years, the natural head position is a stable reference point for cephalometric analysis. Therefore, the natural head position under the cephalometric film for cephalometric analysis is acceptable