Veneer vs. core failure in adhesively bonded all-ceramic crown layers.
Joining a brittle veneer to a strong ceramic core with an adhesive offers potential benefits over current fabrication methods for all-ceramic crowns. We tested the hypothesis that such joining can withstand subsurface radial cracking in the veneer, from enhanced flexure in occlusal loading, as well as in the core. Critical conditions to initiate fractures were investigated in model crown-like layer structures consisting of glass veneers epoxy-joined onto alumina or zirconia cores, all bonded to a dentin-like polymer base. The results showed a competition between critical loads for radial crack initiation in the veneers and cores. Core radial cracking was relatively independent of adhesive thickness. Zirconia cores were much less susceptible to fracture than alumina, attributable to a relatively high strength and low modulus. Veneer cracking did depend on adhesive thickness. However, no significant differences in critical loads for veneer cracking were observed for specimens containing alumina or zirconia cores.
Lee
J J-W
JJ
Materials Science and Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8520, Gaithersburg, MD 20899-8520, USA.
Kwon
J-Y
JY
Bhowmick
S
S
Lloyd
I K
IK
Rekow
E D
ED
Lawn
B R
BR
D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D001732:Bite Force; D003442:Crowns; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D003801:Dental Veneers; D004548:Elasticity; D004853:Epoxy Resins / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D018583:Pliability; D011076:Polycarboxylate Cement / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry
D003764:Dental Materials; D004853:Epoxy Resins; D011076:Polycarboxylate Cement; D011108:Polymers; D019279:Resin Cements; D003776:Dental Porcelain; C005506:polycarbonate; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide