Tsang K H, Cooke M S
University of Hong Kong.
Eur J Orthod. 1999 Feb;21(1):1-13. doi: 10.1093/ejo/21.1.1.
Cephalometric analysis conventionally requires radiographic exposure which may not be compatible with the growing concern over radiation hazards. Recently, the Dolphin Workstation Imaging System introduced to the dental profession a non-radiographic system, called the DigiGraph Workstation which may be an alternative to cephalometric radiography. The aims of this study were to compare the validity and reproducibility of cephalometric measurements obtained from the DigiGraph Workstation with conventional cephalometric radiographs. The sample consisted of 30 human dry skulls. Two replicated sets of lateral cephalograms were obtained with steel ball markers placed at the majority of the cephalometric landmarks. Duplicate tracings prepared from each radiograph were digitized to obtain cephalometric measurements using the computer software, Dentofacial Planner. For the DigiGraph Workstation, double sonic digitizations were repeated twice for each skull, on two occasions. Fifteen angular and one linear measurements were obtained from both methods and these findings compared using ANOVA, paired t-tests and F-tests. All, except one, cephalometric measurement showed significant differences between the two methods (P < 0.0001). The DigiGraph Workstation consistently produced higher values in 11 measurements (mean differences +0.5 to +15.7 degrees or mm) and lower values in four measurements (mean differences -0.2 to -3.5 degrees). The standard deviations of the differences between readings of both methods were large (0.4-5.8 degrees or mm). The reproducibility of the DigiGraph Workstation measurements was lower than that of the radiographic measurements. The method error of the DigiGraph Workstation ranged from 7 to 70 per cent, while that of radiographic tracings was less than 2 per cent. It was concluded that measurements obtained with the DigiGraph Workstation should be interpreted with caution.
传统的头影测量分析需要进行放射摄影曝光，这可能与人们对辐射危害日益增长的担忧不相容。最近，海豚工作站成像系统向牙科行业推出了一种非放射成像系统，称为数字图像工作站，它可能是头影测量放射摄影的一种替代方法。本研究的目的是比较从数字图像工作站获得的头影测量结果与传统头影测量放射照片的有效性和可重复性。样本包括30个人类干燥颅骨。在大多数头影测量标志点放置钢球标记，获得两组重复的侧位头影图。从每张放射照片制备的重复描图被数字化，以使用计算机软件“牙颌面规划师”获得头影测量结果。对于数字图像工作站，对每个颅骨在两个不同时间重复进行两次双声数字化。从两种方法中获得了15个角度测量值和1个线性测量值，并使用方差分析、配对t检验和F检验对这些结果进行比较。除一项外，所有头影测量在两种方法之间均显示出显著差异（P < 0.0001）。数字图像工作站在11项测量中始终产生较高的值（平均差异为+0.5至+15.7度或毫米），在4项测量中产生较低的值（平均差异为-0.2至-3.5度）。两种方法读数之间差异的标准差较大（0.4 - 5.8度或毫米）。数字图像工作站测量的可重复性低于放射摄影测量。数字图像工作站的方法误差范围为7%至70%，而放射摄影描图的方法误差小于2%。得出的结论是，使用数字图像工作站获得的测量结果应谨慎解释。
