Reddy M S
Department of Periodontics, University of Alabama School of Dentistry, Birmingham.
J Periodontol. 1992 Dec;63(12 Suppl):1078-84. doi: 10.1902/jop.1992.63.12s.1078.
Radiographic methods are commonly utilized to assess periodontal bone changes in clinical trials. Radiographs are unique as a data source in that they provide a permanent visual record of the bone support and allow for linear, area, and volume measurements of periodontal lesions. The major limiting factors in the use of radiographic outcomes measures are geometric distortion and radiographic processing errors. The use of standardized methods and computer algorithms has reduced the effect of these errors on data from radiographs. Radiographic analysis in clinical trials is largely done in digital format by indirect digitizing film with a video camera. Direct digital detectors are now available for intra-oral use. The use of a direct detector eliminates the need for film processing and allows for dose reduction. The detectors currently available are limited in size and resolution. Subtraction radiography allows for area and volume estimates of bone gain or loss. The subtraction methods are highly precise, but are also technically exacting and labor intensive. The clinical trial hypothesis, size, length, and accuracy required should be the final consideration in choosing a radiographic method.
在临床试验中，放射照相方法通常用于评估牙周骨的变化。X线片作为一种数据来源具有独特性，因为它们能提供骨支持的永久性视觉记录，并允许对牙周病变进行线性、面积和体积测量。使用放射照相结果测量的主要限制因素是几何失真和放射照相处理误差。标准化方法和计算机算法的使用减少了这些误差对X线片数据的影响。临床试验中的放射照相分析主要通过用摄像机间接数字化胶片以数字格式进行。现在有直接数字探测器可用于口腔内。直接探测器的使用消除了胶片冲洗的需要，并可减少剂量。目前可用的探测器在尺寸和分辨率方面受到限制。减影放射照相可对骨量增加或减少进行面积和体积估计。减法方法非常精确，但技术要求也很高且劳动强度大。在选择放射照相方法时，临床试验的假设、规模、时长和所需的准确性应是最终考虑因素。
