Mason C, Papadakou P, Roberts G J
Department of Paediatric Dentistry, Eastman Dental Institute for Oral Health Care Sciences, University of London, UK.
Eur J Orthod. 2001 Feb;23(1):25-34. doi: 10.1093/ejo/23.1.25.
This study compared two different radiographic techniques for localization of impacted maxillary canines: vertical parallax (from a panoramic and a maxillary anterior occlusal radiograph) and magnification (from a single panoramic radiograph). The radiographs and the information regarding the impacted canines were obtained retrospectively from records of patients treated in the Day Stay Unit of the Eastman Dental Hospital. The two different radiographic techniques were tested blind and compared for localization of the impacted canine by six examiners. The 'gold standard' used for the radiographic comparisons was the true position of the canine as recorded at operation. The results showed a wide variation between the six examiners in the prediction of the canine position with the two different techniques. Localization with vertical parallax was more successful overall than with magnification, although the difference failed to reach significance. Seventy-six per cent of the impacted canines could be successfully located with vertical parallax and 66 per cent with magnification. Further analysis showed that, while almost 90 per cent of the palatally impacted canines could be correctly detected with both techniques, less than half of the buccal canines could be detected with parallax and only one in 10 buccal canines could be detected with magnification. If a canine is suspected to be buccally placed from its appearance on a panoramic film and cannot be palpated, further views are justified.
垂直视差法（来自全景片和上颌前部咬合片）和放大法（来自单张全景片）。这些X光片以及关于阻生尖牙的信息是从伊斯特曼牙科医院日间病房治疗的患者记录中回顾性获取的。由六位检查者在不知情的情况下对这两种不同的影像学技术进行测试，并比较它们对阻生尖牙的定位情况。用于影像学比较的“金标准”是手术记录的尖牙真实位置。结果显示，六位检查者使用这两种不同技术预测尖牙位置时存在很大差异。总体而言，垂直视差法的定位比放大法更成功，尽管差异未达到显著水平。76%的阻生尖牙可通过垂直视差法成功定位，66%可通过放大法定位。进一步分析表明，虽然两种技术对近90%的腭侧阻生尖牙都能正确检测，但垂直视差法对颊侧尖牙的检测不到一半，放大法对颊侧尖牙的检测仅为十分之一。如果根据全景片上的表现怀疑尖牙位于颊侧且无法触诊，那么进一步的检查是合理的。
