J Adv Prosthodont.  2015 Oct;7(5):349-357. 10.4047/jap.2015.7.5.349.

Effects of core characters and veneering technique on biaxial flexural strength in porcelain fused to metal and porcelain veneered zirconia

• Oh JW
• Song KY
• Ahn SG
• Park JM
• Lee MH
• Seo JM

• KMID: 2083877
• DOI: http://doi.org/10.4047/jap.2015.7.5.349

Abstract

PURPOSE
The purpose of this study was to assess the impact of the core materials, thickness and fabrication methods of veneering porcelain on prosthesis fracture in the porcelain fused to metal and the porcelain veneered zirconia.
MATERIALS AND METHODS
Forty nickel-chrome alloy cores and 40 zirconia cores were made. Half of each core group was 0.5 mm-in thickness and the other half was 1.0 mm-in thickness. Thus, there were four groups with 20 cores/group. Each group was divided into two subgroups with two different veneering methods (conventional powder/liquid layering technique and the heat-pressing technique). Tensile strength was measured using the biaxial flexural strength test based on the ISO standard 6872:2008 and Weibull analysis was conducted. Factors influencing fracture strength were analyzed through three-way ANOVA (alpha< or =.05) and the influence of core thickness and veneering method in each core materials was assessed using two-way ANOVA (alpha< or =.05).
RESULTS
The biaxial flexural strength test showed that the fabrication method of veneering porcelain has the largest impact on the fracture strength followed by the core thickness and the core material. In the metal groups, both the core thickness and the fabrication method of the veneering porcelain significantly influenced on the fracture strength, while only the fabrication method affected the fracture strength in the zirconia groups.
CONCLUSION
The fabrication method is more influential to the strength of a prosthesis compared to the core character determined by material and thickness of the core.

Keyword

Zirconia; Metal ceramic; Pressed ceramic; Dental porcelain; Tensile strength

MeSH Terms

Alloys
Dental Porcelain*
Prostheses and Implants
Tensile Strength
Alloys
Dental Porcelain

Figure

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  Fig. 1 Biaxial flexural strength was measured by the universal testing machine.

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  Fig. 2 Fracture status of the fragmented sample was observed through the optical microscope.

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  Fig. 3 Probability Weibull was analyzed for group comparisons.

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