Department of Oral Surgery, Oral Medicine and Dentomaxillofacial Radiology, School of Dental Medicine, University of Geneva, Switzerland.
Dentomaxillofac Radiol. 2013;42(2):20110429. doi: 10.1259/dmfr.20110429.
Conventional panoramic radiography, a widely used radiographic examination tool in implant treatment planning, allows evaluation of the available bone height before inserting posterior mandibular implants. Image distortion and vertical magnification due to projection geometry is well described for rotational panoramic radiographs. To assess the accuracy of vertical height measurements on direct digital panoramic radiographs, implants and metal balls positioned in the posterior mandible were used as radio-opaque reference objects. The reproducibility of the measuring method was assessed by the inter- and intraobserver agreements.
Direct digital panoramic radiographs, performed using a Kodak 8000C (Eastman Kodak Company, Rochester, NY), of 17 partially edentulous patients (10 females, 7 males, mean age 65 years) were selected from an X-ray database gathered during routine clinical evaluation of implant sites. Proprietary software and a mouse-driven calliper were used to measure the radiological length of 25 implants and 18 metal reference balls, positioned in mandibular posterior segments. The distortion ratio (DR) was calculated by dividing the radiological implant length by the implant's real length and the radiological ball height by the ball's real height.
Mean vertical DR was 0.99 for implants and 0.97 for balls, and was unrelated to mandibular sites, side, age, gender or observer. Inter- and intraobserver agreements were acceptable for both reference objects.
Vertical measurements had acceptable accuracy and reproducibility when a software-based calibrated measurement tool was used, confirming that digital panoramic radiography can be reliably utilized to determine the pre-operative implant length in premolar and molar mandibular segments.
传统全景放射摄影术是一种广泛应用于种植体治疗计划的放射学检查工具，可用于评估下颌后牙种植体植入前的可用骨高度。旋转全景放射摄影术很好地描述了由于投影几何形状引起的图像失真和垂直放大。为了评估直接数字化全景放射摄影术上垂直高度测量的准确性，将放置在下颌后牙区的种植体和金属球用作不透射线的参考物体。通过观察者内和观察者间的一致性来评估测量方法的重复性。
从常规临床评估种植部位的 X 射线数据库中选择了 17 名部分无牙患者（10 名女性，7 名男性，平均年龄 65 岁）的直接数字化全景放射照片。使用柯达 8000C（柯达公司，罗切斯特，纽约）拍摄。使用专有软件和鼠标驱动的卡尺测量 25 个种植体和 18 个金属参考球在下颌后段的影像学长度。通过将影像学植入物长度除以植入物的实际长度，将影像学球高度除以球的实际高度来计算失真比（DR）。
种植体的平均垂直 DR 为 0.99，球的平均垂直 DR 为 0.97，与下颌部位、侧别、年龄、性别或观察者无关。两种参考物体的观察者内和观察者间的一致性均可以接受。
当使用基于软件的校准测量工具时，垂直测量具有可接受的准确性和可重复性，这证实了数字全景放射摄影术可用于可靠地确定下颌前磨牙和磨牙段的术前植入物长度。
