Cyclic fatigue in water of veneer-framework composites for all-ceramic dental bridges.
OBJECTIVE
Ceramic materials applied in dentistry may exhibit significant subcritical crack growth due to the severe cyclic loading in the aqueous environment encountered in the mouth during mastication. The authors report on the subcritical crack growth behavior of three dental restoration systems (Empress 2/IPS Eris, TZP/Cercon S and Inceram-Zirconia/Vita VM7) under cyclic loading in water, in order to establish guidelines for the use and design of long-lifetime all-ceramic posterior bridges.


METHODS
Inert strength and lifetime tests under cyclic loading in an aqueous environment were performed in a mechanical bending apparatus and evaluated with Weibull statistics.


RESULTS
Subcritical crack growth occurred predominantly in the outer veneer layer of the veneer-framework composites. The apatite-based veneer (IPS Eris) was more susceptible to subcritical crack propagation compared to the feldspathic glass veneers (Cercon S and Vita VM7).


CONCLUSIONS
Dental restoration systems containing apatite-based veneers and weak frameworks (Empress 2/IPS Eris) are not recommended for the fabrication of all-ceramic bridges in the molar region. Conversely, veneer-framework systems consisting of feldspathic glass veneers and tough zirconia-based frameworks (TZP/Cercon S and Inceram-Zirconia/Vita VM7) may exhibit lifetimes longer than 20 years if the bridge connector is properly designed.
Studart
André R
AR
Department of Materials, ETH-Zürich, Zurich, Switzerland. andre.studart@mat.ethz.ch
Filser
Frank
F
Kocher
Peter
P
Lüthy
Heinz
H
Gauckler
Ludwig J
LJ
D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D001031:Apatites / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D003801:Dental Veneers; D003779:Denture Design; D003829:Denture, Partial; D004548:Elasticity; D006801:Humans; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D018583:Pliability; D017680:Potassium Compounds / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014867:Water / Q000737:chemistry*; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
D000538:Aluminum Silicates; D001031:Apatites; D003764:Dental Materials; C118557:Empress 2; C500744:Eris ceramic; D018020:Lithium Compounds; D017680:Potassium Compounds; C499362:yttria stabilized tetragonal zirconia; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; C070870:In-Ceram; D015019:Yttrium; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide