Moilanen Pauliina, Hjerppe Jenni, Lassila Lippo V J, Närhi Timo O
1 Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.
2 Departments of Oral and Maxillofacial Diseases, Helsinki University Hospital, Helsinki, Finland.
J Oral Implantol. 2018 Oct;44(5):330-334. doi: 10.1563/aaid-joi-D-17-00249. Epub 2018 May 15.
New monolithic zirconia materials can be used to fabricate full-contour fixed dental prostheses with the computer-aided design/computer-aided manufacturing (CAD/CAM) method. The aim of this study was to examine the fracture strength and precision of fit of screw-retained monolithic zirconia crowns made directly on implants or by cementing on prefabricated titanium (Ti) bases. Monolithic screw-retained implant crowns (n = 6) were produced by CAD/CAM method using partially (PSZ) and fully stabilized (FSZ) zirconia. Industrially produced zirconia crowns were used as a reference. A lateral incisor study model was made onto an implant replica. Crowns were produced either directly on the implant or through cementing on a prefabricated titanium base (PSZ+Ti, FSZ+Ti). The crowns were tightened to implant replicas with a torque of 35 Ncm. The gap between the replica and the abutment or crown was measured from ×400 scanning electron microscope images for precision of fit. Mechanical testing until failure was completed with a universal testing machine with loading angle of 45°. Statistical analysis was performed (analysis of variance). Mean (±SD) failure loads were 259 ± 23 (PSZ), 140 ± 13 (FSZ), 453 ± 25 (PSZ+Ti), 439 ± 41 (FSZ+Ti), and 290 ± 39 (Procera). Mean (±SD) gap values were 2.2 ± 0.2 (PSZ), 2.5 ± 1.0 (FSZ), 7.0 ± 1.0 (PSZ+Ti), 7.7 ± 1.6 (FSZ+Ti), and 6.7 ± 1.7 (Procera). Monolithic zirconia crowns with a Ti base clearly show higher fracture strengths than the crowns fixed directly on the implant surface. Better marginal fit can be achieved with direct zirconia crowns than with crowns on a titanium base or industrially produced zirconia crowns.
新型整体式氧化锆材料可用于通过计算机辅助设计/计算机辅助制造（CAD/CAM）方法制作全冠固定义齿。本研究的目的是检验直接制作在种植体上或通过粘结在预制钛（Ti）基台上的螺丝固位整体式氧化锆冠的断裂强度和适合精度。使用部分稳定（PSZ）和完全稳定（FSZ）氧化锆，通过CAD/CAM方法制作整体式螺丝固位种植体冠（n = 6）。使用工业生产的氧化锆冠作为对照。在种植体复制体上制作侧切牙研究模型。冠要么直接制作在种植体上，要么通过粘结在预制钛基台上（PSZ+Ti、FSZ+Ti）。用35 Ncm的扭矩将冠拧紧到种植体复制体上。从×400扫描电子显微镜图像测量复制体与基台或冠之间的间隙，以评估适合精度。使用加载角度为45°的万能试验机进行直至破坏的力学测试。进行统计分析（方差分析）。平均（±标准差）破坏载荷分别为259±23（PSZ）、140±13（FSZ）、453±25（PSZ+Ti）、439±41（FSZ+Ti）和290±39（Procera）。平均（±标准差）间隙值分别为2.2±0.2（PSZ）、2.5±1.0（FSZ）、7.0±1.0（PSZ+Ti）、7.7±1.6（FSZ+Ti）和6.7±1.7（Procera）。带有钛基台的整体式氧化锆冠的断裂强度明显高于直接固定在种植体表面的冠。直接制作的氧化锆冠比钛基台上的冠或工业生产的氧化锆冠能获得更好的边缘适合性。
