Comparative mechanical property characterization of 3 all-ceramic core materials.
OBJECTIVE
The biaxial flexural strength and fracture toughness for 3 representative types of ceramic core materials were studied to (1) ascertain the ranking of the 3 ceramic types for strength and toughness, and (2) provide clinicians with more information to predict clinical outcomes. The former aim was deemed important in view of the importance of flaw size in the relationship between failure stress and fracture toughness of brittle materials.


METHODS
The 3 representative ceramic types included a leucite-reinforced glass, a glass-infiltrated sintered alumina, and a high-purity, high-density alumina. The biaxial flexural strength was measured with the piston-on-3-ball method. The plane-strain fracture toughness was measured with the short-bar chevron-notch method.


RESULTS
The biaxial flexural strengths of the high-purity, high-density alumina and glass-infiltrated sintered alumina ceramic core types were significantly higher than that of the leucite-reinforced glass ceramic type. The glass-infiltrated sintered alumina was significantly higher in fracture toughness than the high-purity, high-density alumina type, which was significantly higher than the leucite-reinforced glass.


CONCLUSIONS
All materials surpassed the minimum strength requirement outlined by the International Standards Organization, and they also had similar strength variability according to their Weibull moduli. The glass-infiltrated sintered alumina and the high-purity, high-density alumina types were significantly stronger and tougher than currently used core materials. However, while the glass-infiltrated sintered alumina had a higher fracture toughness than the high-purity, high-density alumina, it had a lower flexural strength.
Wen
M Y
MY
American Dental Association Health Foundation, Paffenbarger Research Center, Gaithersburg, Maryland, USA.
Mueller
H J
HJ
Chai
J
J
Wozniak
W T
WT
D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D000704:Analysis of Variance; D003776:Dental Porcelain / Q000737:chemistry*; D004548:Elasticity; D019544:Equipment Failure Analysis; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D016062:Porosity; D011176:Post and Core Technique; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013499:Surface Properties; D016019:Survival Analysis; D013718:Tensile Strength
C105314:AllCeram; D000538:Aluminum Silicates; C075815:IPS-Empress ceramic; D003776:Dental Porcelain; C078519:leucite; C070870:In-Ceram; D000537:Aluminum Oxide