OBJECTIVE The aim of this study was to evaluate marginal fit of yttrium tetragonal zirconia polycrystals (Y-TZP)' copings with different finish line designs fabricated with various digital scanners and milling systems. METHODS Three model plastic teeth were prepared with three finish line designs: Design-1, continuous chamfer; Design-2, chamfer with shallow depression; Design-3, chamfer with deep depression. The "master models" were replicated using elastomeric polyvinyl siloxane impression material and poured in type IV stone generating 90 dies, 30 dies for each design. Dies were scanned and copings were milled utilizing three digital scanners and computer-aided design/computer-aided manufacturing (CAD/CAM) systems: System-1, InEos Red Scan (Sirona Dental Systems, Germany), Vitablocks® Mark II (VITA, Germany) copings milled by Cerec® inLab (Sirona Dental Systems, Germany); System-2, Cerec® AC Connect with BlueCam (Sirona Dental Systems, Germany), Vitablocks® Mark II (VITA, Germany) copings milled by Cerec® inLab (Sirona Dental Systems, Germany); and System-3, NobleProcera™ Optical Scanner (NobleBiocare™), procera zirconia coping milled by a Noble Procera™ milling machine (NobleBiocare™). Copings were seated on their respective "master models" and secured with uniform force. Eight measurements per coping were performed at pre-established points, with a metallurgical microscope (Zeiss, Germany) connected to a high precision digital video-micrometer (Javelin JV6000, California, USA) at 200 × magnification. RESULTS The tested systems demonstrated marginal gaps ranging from 12.4 to 26.6 µm. Results for marginal fit of milled copings fabricated using three systems with different finish line designs differed significantly (p < 0.05). Procera zirconia copings scanned and milled with NobleProcera™ exhibited significantly lower marginal gaps compared to other specimen groups. However, InEos Red Scan/Vitablocks® Mark II/Cerec® inLab showed maximum marginal gaps among the study specimens. CONCLUSIONS CAD-CAM manufactured Y-TZP' copings exhibited marginal gaps ranging from 12.49 to 26.6 µm. The CAD-CAM fabrication system was a significant factor influencing the marginal misfit of Y-TZP' copings. Margin design exhibited system dependent influence on the marginal misfit. Marginal misfit observed for all systems were within clinically acceptable parameters.

中文翻译：

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研磨系统和边缘配置对钇稳定的四方氧化锆多晶 (Y-TZP)' 顶盖配合的影响

目的 本研究的目的是评估使用各种数字扫描仪和铣削系统制造的具有不同终点线设计的钇四方氧化锆多晶 (Y-TZP) 顶盖的边缘拟合。方法 制备三个模型塑料齿，三个终点线设计：Design-1，连续倒角；设计二，浅凹陷倒角；设计 3，倒角深度凹陷。使用弹性聚乙烯硅氧烷印模材料复制“主模型”并倒入 IV 型石材中，生成 90 个模具，每个设计 30 个模具。使用三台数字扫描仪和计算机辅助设计/计算机辅助制造 (CAD/CAM) 系统对模具进行扫描并铣削牙冠：System-1、InEos Red Scan（Sirona Dental Systems，德国）、Vitablocks® Mark II（VITA、德国）由 Cerec® inLab（Sirona Dental Systems，德国）铣削的牙冠；System-2、Cerec® AC Connect with BlueCam（Sirona Dental Systems，德国）、Vitablocks® Mark II（VITA，德国）由 Cerec® inLab（Sirona Dental Systems，德国）铣削的牙冠；和 System-3，NobleProcera™ 光学扫描仪 (NobleBiocare™)，由 Noble Procera™ 铣床 (NobleBiocare™) 研磨的 procera 氧化锆内冠。顶盖位于各自的“主模型”上，并用均匀的力量固定。每个顶盖在预先确定的点进行八次测量，金相显微镜（Zeiss，德国）连接到高精度数字视频测微计（Javelin JV6000，California，USA），放大倍数为 200 倍。结果 测试系统显示出从 12.4 到 26.6 µm 的边际间隙。使用具有不同终点线设计的三个系统制造的铣削顶盖的边缘拟合结果显着不同（p < 0.05）。与其他样本组相比，使用 NobleProcera™ 扫描和研磨的 Procera 氧化锆内冠的边缘间隙显着降低。然而，InEos Red Scan/Vitablocks® Mark II/Cerec® inLab 显示出研究样本之间的最大边缘间隙。结论 CAD-CAM 制造的 Y-TZP' 内冠显示出 12.49 至 26.6 µm 的边缘间隙。CAD-CAM 制造系统是影响 Y-TZP 内冠边缘错位的重要因素。边际设计对边际失配表现出系统依赖性影响。观察到的所有系统的边际失配均在临床可接受的参数范围内。