Kirsch Corinna, Ender Andreas, Attin Thomas, Mehl Albert
Division for Computerized Restorative Dentistry, Clinic for Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, 11 Plattenstrasse, 8032, Zurich, Switzerland.
Clinic for Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, 11 Plattenstrasse, 8032, Zurich, Switzerland.
Clin Oral Investig. 2017 Mar;21(2):551-558. doi: 10.1007/s00784-016-1916-y. Epub 2016 Jul 28.
Milling is a crucial step in producing restorations using computer-aided design and computer-aided manufacturing (CAD/CAM) systems. In this study the trueness of currently available milling devices was evaluated.
Thirty clinical cases (ten inlays, ten crowns, ten onlays) were milled from ceramic blocks using four different milling approaches: five axis with IMES CORiTEC 450i, four axis with CEREC MCXL, four axis with CEREC MCXL-EF and five axis with inLab MCX5. The milled restorations were scanned and the occlusal and inner surfaces compared to the originally calculated 3D surface using difference analysis software. The (90-10 %) / 2 percentile of the distances were calculated and analysed using one-way ANOVA with the post hoc Scheffé test (α = 0.05). Chipping of marginal areas were visually examined and analysed using one-way ANOVA with a post hoc Tamhane test (α = 0.05).
At inner surfaces, the milling trueness of IMES (33.9 ± 16.3 μm), X5 (32.3 ± 9.7 μm) and MCXL-EF (34.4 ± 7.5 μm) was significantly better (p < 0.001) than that of MCXL (62.1 ± 17.1 μm). At occlusal surfaces, MCXL-EF (25.7 ± 9.3 μm) showed significant higher accuracy (p < 0.001) than MCXL (48.7 ± 23.3 μm) and X5 (40.9 ± 20.4 μm). IMES produced the most chipping (p < 0.001).
Five-axis milling devices yield high trueness. MCXL-EF is competitive and may allow chairside fabrication with good milling results.
Accurate milling is required for well-fitting restorations and thereby requires fewer manual finishing steps, yields smaller marginal gaps, resistance to secondary caries and longevity of restorations.
铣削是使用计算机辅助设计与计算机辅助制造（CAD/CAM）系统制作修复体的关键步骤。本研究评估了目前可用铣削设备的精度。
使用四种不同的铣削方法从陶瓷块铣削30个临床病例（10个嵌体、10个全冠、10个高嵌体）：使用IMES CORiTEC 450i进行五轴铣削、使用CEREC MCXL进行四轴铣削、使用CEREC MCXL-EF进行四轴铣削以及使用inLab MCX5进行五轴铣削。对铣削后的修复体进行扫描，并使用差异分析软件将咬合面和内表面与最初计算的3D表面进行比较。计算距离的（90 - 10%）/2百分位数，并使用单因素方差分析和事后Scheffé检验（α = 0.05）进行分析。目视检查边缘区域的崩瓷情况，并使用单因素方差分析和事后Tamhane检验（α = 0.05）进行分析。
在内表面，IMES（33.9 ± 16.3μm）、X5（32.3 ± 9.7μm）和MCXL-EF（34.4 ± 7.5μm）的铣削精度显著优于MCXL（62.1 ± 17.1μm）（p < 0.001）。在咬合面，MCXL-EF（25.7 ± 9.3μm）的精度显著高于MCXL（48.7 ± 23.3μm）和X5（40.9 ± 20.4μm）（p < 0.001）。IMES产生的崩瓷最多（p < 0.001）。
五轴铣削设备精度高。MCXL-EF具有竞争力，可能允许在椅旁制作并获得良好的铣削效果。
精确的铣削对于贴合良好的修复体是必需的，从而需要更少的手工修整步骤，产生更小的边缘间隙，抵抗继发龋并延长修复体的使用寿命。
