Influence of thermomechanical fatigue loading on the fracture resistance of all-ceramic posterior crowns.
This study evaluated the fracture resistance and the survival rate of different all-ceramic crowns in-vitro after thermomechanical fatigue loading in comparison to porcelain-fused-to-metal posterior crowns. Sixteen crowns for human mandibular first molars were made of each of the following: Cercon, IPS-Empress 2 In-Ceram Zirconia, Procera AllZircon and porcelain-fused-to-metal. Half of the specimens of each group was thermocycled and dynamically loaded using a chewing simulator All samples were thereafter tested for the maximum fracture resistance. The survival rates after 1-2 million cycles in the artificial mouth were 100% in all the tested crown systems. The chewing simulation and thermocycling did not significantly decrease the fracture strength of the ceramic crowns (P>0.005). The median fracture load of Cercon, Procera AllZircon, In-Ceram Zirconia and PFM was significantly higher than IPS-Empress 2 both for loaded and non loaded groups (P<0.005) while the difference between Cercon, Procera AllZircon, In-Ceram Zirconia and PFM was not significant (P>0.005). All-ceramic systems showed fracture load values similar to those of porcelain-fused-to-metal molar crowns and therefore may be considered for use in clinical studies.
Senyilmaz
Dilek Pinar
DP
Hacettepe University, Faculty of Dentistry, Department of Prosthodontics, Sihhiye/Ankara, Turkey. pinarsenyilmaz@yahoo.com
Canay
Senay
S
Heydecke
Guido
G
Strub
Joerg Rudolf
JR
D002858:Chromium Alloys; D003442:Crowns; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D018020:Lithium Compounds; D016876:Metal Ceramic Alloys; D008963:Molar; D018709:Statistics, Nonparametric; D015040:Zirconium
D002858:Chromium Alloys; D018020:Lithium Compounds; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide