CAD-CAM Processing for All Ceramic Dental Restorations

Author(s):  
Alexandru Eugen Petre
2009 ◽  
Vol 88 (7) ◽  
pp. 673-676 ◽  
Author(s):  
J. Ebert ◽  
E. Özkol ◽  
A. Zeichner ◽  
K. Uibel ◽  
Ö. Weiss ◽  
...  

CAD/CAM milling systems provide a rapid and individual method for the manufacturing of zirconia dental restorations. However, the disadvantages of these systems include limited accuracy, possible introduction of microscopic cracks, and a waste of material due to the principle of the ‘subtractive process’. The hypothesis of this study was that these issues can be overcome by a novel generative manufacturing technique, direct inkjet printing. A tailored zirconia-based ceramic suspension with 27 vol% solid content was synthesized. The suspension was printed on a conventional, but modified, drop-on-demand inkjet printer. A cleaning unit and a drying device allowed for the build-up of dense components of the size of a posterior crown. A characteristic strength of 763 MPa and a mean fracture toughness of 6.7 MPam0.5 were determined on 3D-printed and subsequently sintered specimens. The novel technique has great potential to produce, cost-efficiently, all-ceramic dental restorations at high accuracy and with a minimum of materials consumption.


2009 ◽  
Vol 620-622 ◽  
pp. 575-578 ◽  
Author(s):  
Xin Pei Ma ◽  
Guang Xin Li ◽  
Zhi Hao Jin ◽  
Ji Hua Chen ◽  
Mao Ju Yang ◽  
...  

Glass-ceramics are especially useful for the dental restorations because of their good biocompatibility, chemical stability, aesthetic, mechanical strength and wear resistance. The aim of this work was to obtain one mica glass-ceramic, which can be easily used for rapid machining into all-ceramic tooth with computer assisted design/computer assisted manufacture (CAD/CAM) devices. In the study, on the base of low melting machinable fluorosilicic mica glass ceramics, the effects of CeO2 and Fe2O3 in SiO2-B2O3-K2O-Na2O-Li2O-Al2O3-MgO-F system on color were studied. By orthogonal experimental design, the effects of crystallized parameters on the color, three point flexural strength and machinability of the glass ceramics were obtained, and the samples were analyzed by differential thermal analysis(DTA), X-ray diffraction (XRD) and scanning electron microscopy(SEM), respectively. Experimental results showed that the glass-ceramics with color close to the tooth can be obtained by adjusting the percentage of CeO2 and Fe2O3, and the glass-ceramics crystallized at 680°C for 2h have excellent mechanical properties and machinability.


2010 ◽  
Vol 30 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Yukimichi TAMAKI ◽  
Yasuhiro HOTTA ◽  
Jun KUNII ◽  
Soichi KURIYAMA ◽  
Daisuke HIGUCHI ◽  
...  

2021 ◽  
Vol 24 (2) ◽  
Author(s):  
Christian Giancarlo Bernal ◽  
Ester Mi Ryoung Lee ◽  
Carlos De Paula Eduardo ◽  
Ana Maria Aparecida Souza ◽  
Luciane Hiramatsu Azevedo

Background: To present the benefits of high power lasers (Er: YAG and Nd: YAG) over the use of the high speed turbine for the extraction of ceramics restorations, without damaging the surfaces of the teeth; being a relatively easier and faster procedure without the use of anesthetic agents, and the preparation of the ceramic restorations and cementing in the single session; with a follow-up of 1 year. Objective: The benefits of lasers over high-speed turbine mechanical instrumentation for crown removal encompass efficient restoration recovery without damage to tooth surfaces; and a relatively easier and faster procedure without the use of anesthetic agents. Methods: The Er: YAG laser (no contact; 3.2-4.0 W, 20 Hz) was used to extract the porcelain prosthesis, followed by a gingivectomy with the Nd: YAG laser on tooth 12 to improve the gingival contour. The dental surfaces where the ceramic prosthesis will be cemented were scanned. Then, CAD / CAM technology was used to make the ceramic veneers that were cemented in the same session. Results: The efficacy the Er:YAG laser energy was observed by the decreased of the time to remove all-ceramic materials through ablation of bonding cements, reducing working time by 75% compared to a high-speed turbine. Conclusions: An Er: YAG laser can safely remove lithium disilicate crowns with the settings used in this study. Laser-assisted removal of all ceramic PDFs is a promising treatment protocol. The use of the Nd: YAG (2.0 W power, short 20Hz, 320 µm optical fiber, in contact) laser allowed gingivoplasty to be performed, automatically cauterizing avoiding post-operative bleeding, and facilitating the preparation of ceramic restorations the same day. The use of high-power lasers and the use of accompanying CAD / CAM technology allowed this clinical case to be completed in a single visit without the use of temporary restorations, achieving absolute patient satisfaction.   Keywords Er:YAG; Nd:YAG; Lithium disilicate ceramic; CAD/CAM.


2000 ◽  
Author(s):  
Van P. Thompson ◽  
Stephen Kao ◽  
Ivory Kirkpatrick

Abstract Teeth are uniquely capable of withstanding high forces (>200 N) with small contact area (< 0.5 mm2) and a high number of fatigue cycles (> 107) with little evidence of damage. Yet the tooth is comprised of an outer very brittle, anisotropic, highly crystalline enamel layer supported by an inner soft, but tough dentin. These structures are joined by a small (appoximately 30 microns wide) transition zone called the dento-enamel junction (DEJ). The DEJ plays a critical role in transfer of stress across the layers of the tooth. How the enamel-dentin complex (EDC) comprised of these layers and the DEJ is able to withstand the high contact loads and high cycle fatigue is not well understood. An understanding of the interplay of the various components would serve as the basis for design of dental ceramic or resin based composite crowns capable of service lives approaching those on natural teeth. Current all ceramic crowns have high failure rates (1–5% per yr) on molar teeth and improved performance is required before CAD-CAM restorations can be successful.


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