Gerlach Niek L, Meijer Gert J, Maal Thomas J J, Mulder Jan, Rangel Frits A, Borstlap Wilfred A, Bergé Stefaan J
Department of Oral and Maxillofacial Surgery, Radboud University Nijmegen, Medical Centre, Nijmegen, The Netherlands.
J Oral Maxillofac Surg. 2010 Apr;68(4):811-7. doi: 10.1016/j.joms.2009.09.059. Epub 2009 Dec 29.
To investigate the reproducibility of 3 different tracing methods to determine a reliable method to define the proper anatomical position of the mandibular canal based on cone beam computed tomography (CBCT) data.
Five dentate and 5 edentate patients were selected at random from the CBCT database. Two independent observers traced both the left and the right mandibular canal using 3-dimensional image-based planning software (Procera System NobelGuide; Nobel Biocare, Göteborg, Sweden). All mandibular canals were traced using 3 different methods. Method I was based on coronal views, also known as cross-sections. Panorama-like reconstructions were the starting point for method II. The third method combined methods I and II.
With respect to interobserver reliability, no significant difference (P = .34) for the various methods was observed. The reproducibility was better in edentate than in dentate jaws (P = .0015). The difference between 2 tracings was the lowest for the combined method: within a range of 1.3 mm in 95% of the course of the canal. The most obvious deviations were mainly seen in the anterior part of the canal.
The best reproducible method for mandibular canal tracing is the combined method III. Between observers, still a mean 95th percentile deviation threshold of 1.3 mm (SD 0.384) is noted, indicating that a safety zone of 1.7 mm should be respected. When planning surgery on CBCT-based data, surgeons should be aware of the obvious deviations located in the region of the anterior loop of the canal.
研究三种不同的追踪方法的可重复性，以确定一种基于锥形束计算机断层扫描（CBCT）数据来定义下颌管正确解剖位置的可靠方法。
从CBCT数据库中随机选取5名有牙患者和5名无牙患者。两名独立观察者使用基于三维图像的规划软件（Procera System NobelGuide；诺贝尔生物保健公司，瑞典哥德堡）追踪左右下颌管。所有下颌管均采用三种不同方法进行追踪。方法I基于冠状位视图，也称为横断面。全景式重建是方法II的起点。第三种方法结合了方法I和方法II。
关于观察者间的可靠性，各方法之间未观察到显著差异（P = 0.34）。无牙颌的可重复性优于有牙颌（P = 0.0015）。联合方法的两次追踪之间的差异最小：在95%的管程范围内差异在1.3毫米以内。最明显的偏差主要出现在管的前部。
下颌管追踪的最佳可重复方法是联合方法III。在观察者之间，仍注意到平均第95百分位数偏差阈值为1.3毫米（标准差0.384），这表明应考虑1.7毫米的安全区。在基于CBCT数据进行手术规划时，外科医生应注意管前环区域存在的明显偏差。
