Modified Y-TZP core design improves all-ceramic crown reliability.
This study tested the hypothesis that all-ceramic core-veneer system crown reliability is improved by modification of the core design. We modeled a tooth preparation by reducing the height of proximal walls by 1.5 mm and the occlusal surface by 2.0 mm. The CAD-based tooth preparation was replicated and positioned in a dental articulator for core and veneer fabrication. Standard (0.5 mm uniform thickness) and modified (2.5 mm height lingual and proximal cervical areas) core designs were produced, followed by the application of veneer porcelain for a total thickness of 1.5 mm. The crowns were cemented to 30-day-aged composite dies and were either single-load-to-failure or step-stress-accelerated fatigue-tested. Use of level probability plots showed significantly higher reliability for the modified core design group. The fatigue fracture modes were veneer chipping not exposing the core for the standard group, and exposing the veneer core interface for the modified group.
Department of Prosthodontics, New York University College of Dentistry, 345 24th St., 804S, New York, NY 10010, USA.
N R F A
NR
Silva
E A
EA
Bonfante
B T
BT
Rafferty
R A
RA
Zavanelli
E D
ED
Rekow
V P
VP
Thompson
P G
PG
Coelho
D002484:Cementation / Q000379:methods; D017076:Computer-Aided Design; D003442:Crowns; D003725:Dental Articulators; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation / Q000379:methods; D003801:Dental Veneers; D017276:Friction; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique; D015203:Reproducibility of Results; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D019246:Tooth Preparation / Q000379:methods; D014867:Water / Q000737:chemistry; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
C483701:Rely X Unicem; D019279:Resin Cements; C499362:yttria stabilized tetragonal zirconia; D014867:Water; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium