M Schmitter1, D Mueller, S Rues. 1. Department of Prosthodontics, Section for Biomaterial Research, University of Heidelberg, 69120 Heidelberg, Germany. Marc_Schmitter@med.uni-heidelberg.de
Abstract
OBJECTIVES: The aim of this in vitro study was to assess the ultimate load to failure of zirconia based crowns veneered with CAD/CAM manufactured ceramic. METHODS: 32 identical, anatoform zirconia (Sirona inCoris ZI, mono L F1) frameworks (thickness 0.6mm) 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 F(max)=108 N). To further investigate the new technique, finite element computations were carried out on the basis of the original geometry. RESULTS: 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. CONCLUSION: The CAD/CAM production of veneers for restorations with zirconia framework is a promising way to reduce failures originating from material fatigue.
OBJECTIVES: The aim of this in vitro study was to assess the ultimate load to failure of zirconia based crowns veneered with CAD/CAM manufactured ceramic. METHODS: 32 identical, anatoform zirconia (Sirona inCoris ZI, mono L F1) frameworks (thickness 0.6mm) 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 F(max)=108 N). To further investigate the new technique, finite element computations were carried out on the basis of the original geometry. RESULTS: 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. CONCLUSION: The CAD/CAM production of veneers for restorations with zirconia framework is a promising way to reduce failures originating from material fatigue.
Authors: Anna Winter; Axel Schurig; Engelke Rasche; Franziska Rösner; Lisa Kanus; Marc Schmitter Journal: J Mater Sci Mater Med Date: 2019-12-23 Impact factor: 3.896