Kurz Michael, Attin Thomas, Mehl Albert
Clinic of Preventive Dentistry, Periodontology, and Cariology, Division of Computerized Restorative Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland.
Clin Oral Investig. 2015 Nov;19(8):2035-43. doi: 10.1007/s00784-015-1440-5. Epub 2015 Mar 7.
This study aims to evaluate the accuracy of a powder-free three-dimensional (3D) measuring system (CEREC Omnicam, Sirona), when scanning the surface of a material at different angles. Additionally, the influence of water was investigated.
Nine different materials were combined with human tooth surface (enamel) to create n = 27 specimens. These materials were: Controls (InCoris TZI and Cerec Guide Bloc), ceramics (Vitablocs® Mark II and IPS Empress CAD), metals (gold and amalgam) and composites (Tetric Ceram, Filtek Supreme A2B and A2E). The highly polished samples were scanned at different angles with and without water. The 216 scans were then analyzed and descriptive statistics were obtained.
The height difference between the tooth and material surfaces, as measured with the 3D scans, ranged from 0.83 μm (±2.58 μm) to -14.79 μm (±3.45 μm), while the scan noise on the materials was between 3.23 μm (±0.79 μm) and 14.24 μm (±6.79 μm) without considering the control groups. Depending on the thickness of the water film, measurement errors in the order of 300-1,600 μm could be observed.
The inaccuracies between the tooth and material surfaces, as well as the scan noise for the materials, were within the range of error for measurements used for conventional impressions and are therefore negligible. The presence of water, however, greatly affects the scan.
The tested powder-free 3D measuring system can safely be used to scan different material surfaces without the prior application of a powder, although drying of the surface prior to scanning is highly advisable.
本研究旨在评估无粉三维（3D）测量系统（CEREC Omnicam，西诺德公司）在不同角度扫描材料表面时的准确性。此外，还研究了水的影响。
将九种不同材料与人类牙齿表面（牙釉质）相结合，制成n = 27个标本。这些材料包括：对照材料（InCoris TZI和CEREC导向块）、陶瓷（维他灵®Mark II和IPS Empress CAD）、金属（金和汞合金）以及复合材料（Tetric Ceram、Filtek Supreme A2B和A2E）。对高度抛光的样本在有水和无水情况下以不同角度进行扫描。然后对216次扫描进行分析并获得描述性统计数据。
通过3D扫描测量，牙齿与材料表面之间的高度差范围为0.83μm（±2.58μm）至 -14.79μm（±3.45μm），在不考虑对照组的情况下，材料上的扫描噪声在3.23μm（±0.79μm）至14.2μm（±6.79μm）之间。根据水膜厚度，可观察到300 - 1600μm量级的测量误差。
牙齿与材料表面之间的测量误差以及材料的扫描噪声在传统印模测量的误差范围内，因此可以忽略不计。然而，水的存在会极大地影响扫描结果。
经测试的无粉3D测量系统可安全用于扫描不同材料表面，无需预先涂抹粉末，不过在扫描前对表面进行干燥处理是非常可取的。
