Xiao N, Sun Y C, Zhao Y J, Wang Y
Center for Digital Dentistry, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing 100081, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2019 Feb 18;51(1):120-130. doi: 10.19723/j.issn.1671-167X.2019.01.022.
To establish a reference dental model used for trueness evaluation of photo-curing 3D printing technologies, and to establish a multidimensional trueness evaluation method based on the reference dental model, which can yield a comprehensive objective evaluating result.
A reference dental model was designed in 3ds Max 2018 software based on the statistical analysis results of dental crown and dental arch of Chinese population in previous studies in order to simulate a real dental model. This model was made up of several simple geometrical configurations, which could minimize the manual measurement error. Physical models were fabricated using three types of photo-curing three-dimensional printers using different techniques: Objet30 Pro (PJ), Projet 3510 HD Plus (MJP), and Perfactory DDP (DLP). The models were scanned by a laser-scanning device and the files were exported in a stereolithography file format. In Geomagic Studio 2012, 3D shape deviations (including overall 3D deviation, flatness error, parallelism error and perpendicularity error) were measured by several commands using the data obtained from the scanning. With regard to the feature size of the simulated dental crown and dental arch, linear measurements (including mesiodistal diameter, buccolingual diameter, crown height of each simulated dental crown and feature size of dental arch) were recorded for selected landmarks using a digital caliper. The measurement results of feature sizes were used to analyze the occlusal plane percentage error and the occlusogingival direction percentage error.
For the 3D shape deviation, the results showed that the printed model made by the Objet30 Pro had the lowest overall 3D deviation, the model made by Projet 3510 HD Plus had the best perpendicularity accuracy and the model made by Perfactory DDP had the best flatness accuracy. In terms of the accuracy of the feature size, the model made by the Objet30 Pro was the most accurate in consideration of the results of the occlusal plane percentage error and the occlusogingival direction percentage error.
The reference dental model and the trueness evaluation method using this model is universally applicable in evaluating the trueness of photo-curing three-dimensional printed dental model and can provide a comprehensive objective evaluating result, which can serve as a reference for the clinical use of photo-curing 3D printing technology.
建立用于光固化3D打印技术精度评估的参考牙模型，并基于该参考牙模型建立多维精度评估方法，以获得全面客观的评估结果。
根据以往研究中中国人群牙冠和牙弓的统计分析结果，在3ds Max 2018软件中设计参考牙模型，以模拟真实牙模型。该模型由几种简单几何构型组成，可将人工测量误差降至最低。使用三种采用不同技术的光固化三维打印机制作物理模型：Objet30 Pro（PJ）、Projet 3510 HD Plus（MJP）和Perfactory DDP（DLP）。通过激光扫描设备对模型进行扫描，并以立体光刻文件格式导出文件。在Geomagic Studio 2012中，使用从扫描获得的数据，通过几个命令测量三维形状偏差（包括整体三维偏差、平面度误差、平行度误差和垂直度误差）。对于模拟牙冠和牙弓的特征尺寸，使用数字卡尺记录选定标志点的线性测量值（包括近远中径、颊舌径、每个模拟牙冠的冠高和牙弓的特征尺寸）。特征尺寸的测量结果用于分析咬合平面百分比误差和咬合龈向百分比误差。
对于三维形状偏差，结果表明，Objet30 Pro制作的打印模型整体三维偏差最低，Projet 3510 HD Plus制作的模型垂直度精度最佳，Perfactory DDP制作的模型平面度精度最佳。在特征尺寸精度方面，考虑到咬合平面百分比误差和咬合龈向百分比误差的结果，Objet30 Pro制作的模型最准确。
参考牙模型及使用该模型的精度评估方法普遍适用于评估光固化三维打印牙模型的精度，并能提供全面客观的评估结果，可为光固化3D打印技术的临床应用提供参考。
