Department of Restorative Dentistry, King's College London Dental Institute, London, UK.
Clin Oral Implants Res. 2010 Jul;21(7):718-25. doi: 10.1111/j.1600-0501.2009.01905.x.
To assess the accuracy of measuring the cortical bone thickness adjacent to dental implants using two cone beam computed tomography (CBCT) systems.
Ten 4 x 11 mm Astra Tech implants were placed at varying distances from the cortical bone in two prepared bovine ribs. Both ribs were scanned in a reproducible position using two different CBCT scanners. Ten examiners each carried out four measurements on all 10 implants using the two CBCT systems: vertical distance between the top of the implant and the alveolar crest (IT-AC), and thickness of the cortical bone from the outer surface of the implant threads at 3, 6 and 9 mm from the top of the implant. Ground sections were prepared and bone thickness was measured using a light microscope and a graticule to give a gold standard (GS) measurement.
The examiner's measurements were significantly different between CBCT systems for the vertical and thickness dimensions (P<0.001) while measuring the cortical bone thickness between 0.3 and 3.7 mm. Within that range, i-CAT NG measurements were consistently underestimated in comparison with the GS. Accuitomo 3D60 FPD measurements closely approximated the GS, except when cortical bone thickness was <0.8 mm. The mean percentage errors from the GS at 3, 6 and 9 mm measurement levels were 68%, 28% and 18%, respectively, for i-CAT NG and 23%, 5% and 6%, respectively, for Accuitomo 3D60 FPD.
Within the limitations of this study, it was concluded that i-CAT NG (voxel size 0.3) may not produce sufficient resolution of the thin cortical bone adjacent to dental implants and, therefore, the measurements may not be accurate; whereas, Accuitomo 3D60 FPD (voxel size 0.125) may produce better resolution and more accurate measurement of the thin bone.
评估两种锥形束计算机断层扫描（CBCT）系统测量牙种植体周围皮质骨厚度的准确性。
将 10 个 4x11mm AstraTech 种植体放置在两个准备好的牛肋骨中，距离皮质骨的不同距离处。两根肋骨以可重复的位置使用两种不同的 CBCT 扫描仪进行扫描。十位检查者每人在两个 CBCT 系统上对所有 10 个种植体进行了四次测量：种植体顶部与牙槽嵴之间的垂直距离（IT-AC），以及从种植体顶部 3、6 和 9mm 处种植体螺纹外表面开始的皮质骨厚度。制备磨片并使用光学显微镜和网格测量骨厚度，以获得金标准（GS）测量值。
检查者的测量值在 CBCT 系统之间存在显著差异，垂直和厚度尺寸（P<0.001），而在测量 0.3 至 3.7mm 之间的皮质骨厚度时。在该范围内，与 GS 相比，i-CAT NG 的测量值始终被低估。Accuitomo 3D60 FPD 的测量值与 GS 非常接近，除了皮质骨厚度<0.8mm 时。在 3、6 和 9mm 测量水平，i-CAT NG 的 GS 平均百分比误差分别为 68%、28%和 18%，Accuitomo 3D60 FPD 的 GS 平均百分比误差分别为 23%、5%和 6%。
在本研究的限制范围内，得出结论，i-CAT NG（体素大小 0.3）可能无法对牙种植体周围的薄皮质骨产生足够的分辨率，因此测量值可能不准确；而 Accuitomo 3D60 FPD（体素大小 0.125）可能会产生更好的分辨率和更准确的薄骨测量值。
