J Korean Acad Prosthodont.  2010 Apr;48(2):94-100.

Fracture strength of zirconia ceramic crowns according to tooth position

• Lee IS
• Kim JM
• Dong JK

Abstract

PURPOSE
The purpose of this study was to compare the fracture strength of the zirconia ceramic crowns according to tooth position. MATERIAL AND METHODS: After 10 metal dies were made for each group, the zirconia ceramic crowns were fabricated using CAD/CAM system (Lava(TM) All-Ceramic System) and each crown was cemented on each metal die with resin cement (Rely X(TM) Unicem). The cemented zirconia ceramic crowns mounted on the testing jig were inclined with 30 degrees to the long axis of the tooth and the universal testing machine was used to measure the fracture strength.
RESULTS
1. The fracture strength of the zirconia ceramic crown in the lower 1st molar (2963 N) had the highest and that in the lower central incisor (1035 N) had the lowest. 2. The fracture strength of zirconia ceramic crown was higher than that of the IPS Empress crowns in all tooth position. 3. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the long axis of the crowns. 4. There were no significant differences on the fracture strength of the zirconia ceramic crowns according to tooth position except in premolar group.
CONCLUSION
Within the limitations of this study, the results suggested that strength of zirconia ceramic crown is satisfactory for clinical use.

Keyword

Zirconia ceramic crown; Fracture strength

MeSH Terms

Axis, Cervical Vertebra
Bicuspid
Ceramics
Collodion
Crowns
Incisor
Molar
Resin Cements
Tooth
Zirconium
Ceramics
Collodion
Resin Cements
Zirconium

Figure

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  Fig. 1. Metal dies were fabricated on upper central incisor (A) and lower 1st molar (B) with 8 degree axial inclination and 2.0 mm incisal reduction and 1.5 mm occlusal reduction.

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  Fig. 2. Zirconia cores were fabricated on upper central incisor (A) and lower 1st molar (B).

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  Fig. 3. Cemented upper zirconia ceramic crowns on the metal die for fracture test (A, central incisor; B, canine; C, 1st premolar; D, 1st molar).

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  Fig. 4. Cemented lower zirconia ceramic crowns on the metal die for fracture test (A, central incisor; B, canine; C, 2nd premolar; D, 1st molar).

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  Fig. 5. Fracture strength test of zirconia ceramic crown using the universal testing machine.

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  Fig. 6. Aspects of fractured zirconia ceramic crowns.

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