Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, Via Caserta 6, 00161 Rome, Italy.
Oncological and Reconstructive Maxillo-Facial Surgery Unit, Policlinico Umberto I, Viale del Policlinico 155, 00161 Rome, Italy.
Int J Environ Res Public Health. 2022 Sep 19;19(18):11834. doi: 10.3390/ijerph191811834.
This retrospective study aims to compare the accuracy of two different CAD/CAM systems in orthognathic surgery. The novelty of this work lies in the method of evaluating the accuracy, i.e., using an Iterative Closest Point (ICP) algorithm, which matches a pair of 2D or 3D point clouds with unknown dependencies of the transition from scan to scan .
The study population was composed of ten patients who presented to the Maxillofacial Surgery Department of the University "Sapienza" of Rome for the evaluation and management of skeletal malocclusions. The patients were divided into two groups, depending on the technique used: group 1: splintless group (custom-made cutting guide and plates); group 2: splint group (using a 3D-printed splint). STL files were imported into Geomagic Control X™ software, which allows for comparison and analysis using an ICP algorithm. The RMSE parameter (3D error) was used to calculate the accuracy. In addition, data were compared in two different patient subgroups. The first subgroup only underwent a monobloc Le Fort I osteotomy (-value = 0.02), and the second subgroup underwent a Le Fort I osteotomy associated with a segmental osteotomy of the maxilla (-value = 0.23).
Group 1 showed a 3D error of 1.22 mm ± SD 0.456, while group 2 showed a 3D error of 1.63 mm ± SD 0.303. These results have allowed us to compare the accuracy of the two CAD/CAM systems (-value = 0.09).
The ICP algorithm provided a reproducible method of comparison. The splintless method would seem more accurate (-value = 0.02) in transferring the surgical programming into the operating room when only a Le Fort I osteotomy is to be performed.
本回顾性研究旨在比较两种不同 CAD/CAM 系统在正颌手术中的准确性。本研究的新颖之处在于评估准确性的方法，即使用迭代最近点（ICP）算法，该算法匹配一对具有未知扫描到扫描转换依赖性的 2D 或 3D 点云。
研究人群由 10 名因骨骼畸形前来罗马“萨皮恩扎”大学颌面外科就诊的患者组成。患者被分为两组，取决于所使用的技术：组 1：无夹板组（定制切割引导器和板）；组 2：夹板组（使用 3D 打印夹板）。STL 文件被导入到 Geomagic Control X™软件中，该软件允许使用 ICP 算法进行比较和分析。使用 RMSE 参数（3D 误差）来计算准确性。此外，还在两个不同的患者亚组中比较了数据。第一个亚组仅接受单颌 Le Fort I 截骨术（-值=0.02），第二个亚组接受 Le Fort I 截骨术和上颌骨节段性截骨术（-值=0.23）。
组 1 的 3D 误差为 1.22 毫米±0.456 标准差，组 2 的 3D 误差为 1.63 毫米±0.303 标准差。这些结果使我们能够比较两种 CAD/CAM 系统的准确性（-值=0.09）。
ICP 算法提供了一种可重复的比较方法。当仅进行 Le Fort I 截骨术时，无夹板方法似乎更准确（-值=0.02），可以将手术编程更准确地转移到手术室中。
