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. 2013 May;5(2):92-7.
doi: 10.4047/jap.2013.5.2.92. Epub 2013 May 30.

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

Taek-Ka Kwon  1 , Hyun-Soon Pak, Jae-Ho Yang, Jung-Suk Han, Jai-Bong Lee, Sung-Hun Kim, In-Sung Yeo
Affiliations

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

Taek-Ka Kwon et al. J Adv Prosthodont. 2013 May.

Abstract

Purpose: All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident.

Materials and methods: Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns.

Results: THE MEAN FRACTURE STRENGTHS WERE AS FOLLOWS: 54.9 ± 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 ± 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain.

Conclusion: The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.

Keywords: All-ceramic crown; Digident CAD/CAM; Fracture strength; Lava CAD/CAM; Zirconia.

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Figures

Fig. 1
Fig. 1
The metal die used for the fracture strength test.
Fig. 2
Fig. 2
Schematic view of the fracture strength determination procedure with CAD/CAM zirconia crowns. The direction of the load applied was 30°, and the loading points were consistently maintained by repositioning the metal die.
Fig. 3
Fig. 3
Fracture strengths of Lava CAD/CAM and Digident CAD/CAM zirconia crowns, expressed as mean (standard deviation).
Fig. 4
Fig. 4
Modes of failure of all-ceramic crowns. There were 3 modes of failure: chipping, fracture at the core-veneer interface, and fracture of the crown core.
Fig. 5
Fig. 5
Photographs after fracture strength tests. A: Lava CAD/CAM crowns showed crown core fracture pattern, B: Digident CAD/CAM crowns showed interfacial fracture pattern of core and veneering porcelain.
See this image and copyright information in PMC

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