Rossouw P E, Benatar M, Stander I, Wynchank S
Department of Orthodontics, University of Stellenbosch, Tygerberg, South Africa.
J Dent Assoc S Afr. 1991 Apr;46(4):223-6.
A critical comparison of three methods for measuring distances between various fiducial points on orthodontic plaster casts is presented. The first method consisted of using a vernier caliper by which direct measurements (Dv) of the distances were recorded. The second method consisted of measuring the same casts using a reflex metrograph (Dm), where the co-ordinates of the points relative to two axes were recorded and the distances between various points were calculated. In the third method, reflection holograms of the casts were made, and the same distances were measured on the holographic images (Dh) using the reflex metrograph. The Wilcoxon sign rank test indicated no significant differences (p greater than 0.1) between measurements made by the various techniques. The means of the different distances scored varied within less than 0.5 mm (Dv-Dh), 0.5mm (Dv-Dm) and 0.2mm Dm-Dh). This study indicated that holograms can provide sufficiently accurate representations of orthodontic study models. Their retention as case records may solve the problem of the storage of orthodontic plaster casts.
本文对三种测量正畸石膏模型上各基准点之间距离的方法进行了批判性比较。第一种方法是使用游标卡尺直接记录距离（Dv）。第二种方法是使用反射式测距仪测量相同的模型（Dm），记录各点相对于两个轴的坐标，并计算各点之间的距离。在第三种方法中，制作模型的反射全息图，并使用反射式测距仪在全息图像上测量相同的距离（Dh）。威尔科克森符号秩检验表明，不同技术所测结果之间无显著差异（p大于0.1）。不同距离测量值的均值差异在0.5毫米以内（Dv-Dh）、0.5毫米（Dv-Dm）和0.2毫米（Dm-Dh）。本研究表明，全息图能够为正畸研究模型提供足够精确的表示。将其作为病例记录保存可以解决正畸石膏模型的存储问题。
