口腔数字化曲面体层摄影失真度的实验研究

Evaluation on distortions of stomatological digital pantomography:an experimental study

目的评价口腔数字化曲面体层摄影的失真度。方法采用在颅骨标本牙槽窝内放置种植体、拍摄颅骨标本在不同位置时的曲面体层X线片的方法,探讨在不同位置时曲面体层X线影像失真率的大小,分析头颅位置改变对失真率的影响,间接了解颌骨的失真度。结果采用Dimaxis Pro软件分析后,不同区域的水平失真率多为负值,垂直失真率变化相对较小,头颅位置的改变对水平和垂直失真率影响也不明显,差异无统计学意义(P>0.05);而直尺加圆规测量不同区域的水平失真率有较大的差异,差异有统计学意义(P<0.05),垂直失真率变化相对较小,头颅位置的改变使水平失真率受到的影响更大,差异有统计学意义(P<0.05)。结论肉眼与直尺观察曲面体层X片始终有较大的失真率,但通过数字化软件分析后可大大降低失真率,方便临床诊断。

Objective To evaluate the distortions of stomatological digital pantomography. Methods A implant was placed in alveolar sockets of the human cranium, in vitro. When implant was installed in the incisor and premolar and molar region of the jaws respectively,the specimens were taken radiographs at three different positions by moving the specimen anterior and posterior on the base of routine position. For each image, the length and diameter of the implant were measured by Dimaxis Pro software or ruler and compasses. Results After analyses of Dimaxis Pro software,most of the horizontal distortions were negative values,the vertical distortions had little changed, and little influences were taken to the horizontal and vertical distortions when the position of the cranium was changed（P〉0. 05）. However, by the way of ruler and compasses measurement,the horizontal distortions of each regions were significantly different. Although each of the vertical distortions changed a lot, there had no statistical differences among them. While the position of the cranium was changed, the influences were taken to the horizontal and vertical distortions significantly（P〈0. 05）. Conclusion To observe the panoramic radiographs through naked eyes and ruler has remarkable distortions. The use of a software program to correct for distortion is more reliable and also very promising.