Chipping behaviour of all-ceramic crowns with zirconia framework and CAD/CAM manufactured veneer
2011; Elsevier BV; Volume: 40; Issue: 2 Linguagem: Inglês
10.1016/j.jdent.2011.12.007
ISSN1879-176X
AutoresMarc Schmitter, D. Mueller, Stefan Rues,
Tópico(s)Endodontics and Root Canal Treatments
ResumoThe aim of this in vitro study was to assess the ultimate load to failure of zirconia based crowns veneered with CAD/CAM manufactured ceramic. 32 identical, anatoform zirconia (Sirona inCoris ZI, mono L F1) frameworks (thickness 0.6 mm) were constructed (Sirona inLab 3.80). Afterwards, 16 crowns were completed using a CAD/CAM manufactured lithium disilicate ceramic veneer (IPS e.max CAD, Ivoclar Vivadent). The remaining 16 frames were veneered using conventional manual layering technique. For the CAD/CAM manufactured veneers, the connection between framework and veneer was accomplished via a glass fusion ceramics. Before fracture tests, half of the specimens underwent thermocycling and chewing simulation (1.2 million chewing cycles, force magnitude Fmax = 108 N). To further investigate the new technique, finite element computations were carried out on the basis of the original geometry. Nearly all (87.5%) conventionally veneered crowns failed already during chewing simulation, whereas crowns with CAD/CAM manufactured veneers were non-sensitive to artificial ageing. Crowns veneered with lithium disilicate ceramic displayed ultimate loads to failure of about 1600 N. The CAD/CAM production of veneers for restorations with zirconia framework is a promising way to reduce failures originating from material fatigue.
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