Brägger U, Häfeli U, Huber B, Hämmerle C H, Lang N P
University of Berne, School of Dental Medicine, Switzerland.
Clin Oral Implants Res. 1998 Aug;9(4):218-24. doi: 10.1034/j.1600-0501.1998.090402.x.
In most of the studies on long-term radiographic evaluations of crestal bone levels adjacent to dental implants, no baseline radiographs taken immediately postsurgically had been obtained. The aim of this study was to test the reproducibility of a simple radiographic method for linear measurements of changes in bone levels and to evaluate changes in crestal bone levels adjacent to non-submerged ITI implants 1 year following the surgical procedure. From 128 patients enrolled in a clinical and radiographic longitudinal study 40 patients also had radiographs taken immediately postsurgically. They were, however, not obtained as "identical" images. The radiographs were mounted onto slides and projected on a screen. Mesially and distally from 57 implants triplicate linear measurements of the distance implant shoulder to bone crest were taken, using known dimensions of the implants as internal reference distances. The median difference of 213 (out of 228 possible) duplicate measurements was 0.00 mm (ranging from -1.72 mm to +1.47 mm when comparing the second to the third reading). Some 81% of the double measurements were within +/- 0.5 mm and the precision was 0.30 mm. In the immediate postoperative radiographs the median mesial bone level was located at 2.07 mm (distally 2.19 mm) from the implant shoulder. A statistically significant amount of bone loss in the first year was observed mesially (median = -0.78 mm) and distally (-0.85 mm) (Wilcoxon matched pairs signed rank test P < or = 0.001). No statistically significant influence of the implant location, the implant length, type of the implant (screw; cylinder) was observed (Kruskal-Wallis P > 0.05). The age of the patients was not correlated significantly to the amount of bone loss observed. In conclusion, methodological limitations existed when evaluating linear bone changes in non-identical radiographs using reference dimensions of the implants. The amount of postsurgical bone loss estimated in other studies was confirmed when using an immediate postoperative radiograph as a baseline.
在大多数关于牙种植体周围嵴顶骨水平的长期影像学评估研究中，术后未立即获取基线X线片。本研究的目的是测试一种用于线性测量骨水平变化的简单影像学方法的可重复性，并评估手术1年后非潜入式ITI种植体周围嵴顶骨水平的变化。在一项临床和影像学纵向研究的128例患者中，40例患者术后也立即进行了X线片拍摄。然而，这些X线片并非“相同”图像。将X线片装在载玻片上并投射到屏幕上。从57颗种植体的近中及远中方向，以种植体已知尺寸作为内部参考距离，对种植体肩部至骨嵴的距离进行三次线性测量。228次可能的重复测量中有213次的中位数差异为0.00mm（第二次与第三次读数比较时，范围为-1.72mm至+1.47mm）。约81%的双次测量在±0.5mm范围内，精度为0.30mm。术后即刻X线片中，近中骨水平距种植体肩部的中位数为2.07mm（远中为2.19mm）。观察到第一年近中（中位数=-0.78mm）和远中（-0.85mm）有统计学意义的骨吸收（Wilcoxon配对符号秩检验P≤0.001）。未观察到种植体位置、种植体长度、种植体类型（螺钉型；圆柱型）有统计学意义的影响（Kruskal-Wallis检验P>0.05）。患者年龄与观察到的骨吸收量无显著相关性。总之，使用种植体参考尺寸评估非相同X线片中的线性骨变化时存在方法学局限性。以术后即刻X线片作为基线时，其他研究中估计的术后骨吸收量得到了证实。
