Swennen Gwen R J, Mommaerts Maurice Y, Abeloos Johan, De Clercq Calix, Lamoral Philippe, Neyt Nathalie, Casselman Jan, Schutyser Filip
Division of Maxillo-Facial Surgery, Department of Surgery, General Hospital St-Jan Bruges, Ruddershove, Bruges, Belgium.
J Craniofac Surg. 2007 May;18(3):533-9. doi: 10.1097/scs.0b013e31805343df.
A detailed visualization of the interocclusal relationship is essential in a three-dimensional virtual planning setup for orthognathic and facial orthomorphic surgery. The purpose of this study was to introduce and evaluate the use of a wax bite wafer in combination with a double computed tomography (CT) scan procedure to augment the three-dimensional virtual model of the skull with a detailed dental surface. A total of 10 orthognathic patients were scanned after a standardized multislice CT scanning protocol with dose reduction with their wax bite wafer in place. Afterward, the impressions of the upper and lower arches and the wax bite wafer were scanned for each patient separately using a high-resolution standardized multislice CT scanning protocol. Accurate fitting of the virtual impressions on the wax bite wafer was done with surface matching using iterative closest points. Consecutively, automatic rigid point-based registration of the wax bite wafer on the patient scan was performed to implement the digital virtual dental arches into the patient's skull model (Maxilim, version 2.0; Medicim NV, St-Niklaas, Belgium). Probability error histograms showed errors of < or =0.16 mm (25% percentile), < or =0.31 mm (50% percentile), and < or =0.92 (90% percentile) for iterative closest point surface matching. The mean registration error for automatic point-based registration was 0.17 +/- 0.07 mm (range, 0.12-0.22 mm). The combination of the wax bite wafer with the double CT scan procedure allowed for the setup of an accurate three-dimensional virtual augmented model of the skull with detailed dental surface. However, from a clinical workload, data handling, and computational point of view, this method is too time-consuming to be introduced in the clinical routine.
在正颌和面部整形手术的三维虚拟规划设置中，详细可视化咬合关系至关重要。本研究的目的是介绍并评估蜡咬合片与双重计算机断层扫描（CT）扫描程序相结合的使用情况，以用详细的牙齿表面增强颅骨的三维虚拟模型。按照标准化的多层CT扫描方案并降低剂量，在10名正颌患者佩戴蜡咬合片的情况下进行扫描。之后，使用高分辨率标准化多层CT扫描方案分别对每位患者的上下牙弓印模和蜡咬合片进行扫描。通过使用迭代最近点的表面匹配，使虚拟印模精确贴合蜡咬合片。随后，对蜡咬合片在患者扫描图像上进行基于点的自动刚性配准，以将数字虚拟牙弓植入患者的颅骨模型（Maxilim，2.0版；Medicim NV，比利时圣尼克拉斯）。概率误差直方图显示，迭代最近点表面匹配的误差<或=0.16毫米（第25百分位数），<或=0.31毫米（第50百分位数），<或=0.92（第90百分位数）。基于点的自动配准的平均配准误差为0.17 +/- 0.07毫米（范围为0.12 - 0.22毫米）。蜡咬合片与双重CT扫描程序的结合能够建立一个带有详细牙齿表面的精确颅骨三维虚拟增强模型。然而，从临床工作量、数据处理和计算的角度来看，这种方法在临床常规中引入过于耗时。
