title: Reliability of metalloceramic and zirconia-based ceramic crowns.
abstract: Despite the increasing utilization of all-ceramic crown systems, their mechanical performance relative to that of metal ceramic restorations (MCR) has yet to be determined. This investigation tested the hypothesis that MCR present higher reliability over two Y-TZP all-ceramic crown systems under mouth-motion fatigue conditions. A CAD-based tooth preparation with the average dimensions of a mandibular first molar was used as a master die to fabricate all restorations. One 0.5-mm Pd-Ag and two Y-TZP system cores were veneered with 1.5 mm porcelain. Crowns were cemented onto aged (60 days in water) composite (Z100, 3M/ESPE) reproductions of the die. Mouth-motion fatigue was performed, and use level probability Weibull curves were determined. Failure modes of all systems included chipping or fracture of the porcelain veneer initiating at the indentation site. Fatigue was an acceleration factor for all-ceramic systems, but not for the MCR system. The latter presented significantly higher reliability under mouth-motion cyclic mechanical testing.
authors.affiliation: Department of Prosthodontics, New York University College of Dentistry, 345 East 24th Street, Room 804-S, New York, NY 10010, USA. nrd1@nyu.edu
authors.forename: N R F A
authors.initials: NR
authors.lastname: Silva
authors.forename: E A
authors.initials: EA
authors.lastname: Bonfante
authors.forename: R A
authors.initials: RA
authors.lastname: Zavanelli
authors.forename: V P
authors.initials: VP
authors.lastname: Thompson
authors.forename: J L
authors.initials: JL
authors.lastname: Ferencz
authors.forename: P G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D002484:Cementation / Q000379:methods; D003188:Composite Resins / Q000737:chemistry; D017076:Computer-Aided Design; D003442:Crowns; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008963:Molar; D010165:Palladium / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D019231:Tooth Preparation, Prosthodontic; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003188:Composite Resins; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; C483701:Rely X Unicem; D019279:Resin Cements; C083568:Z100 composite resin; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D010165:Palladium; D012822:Silicon Dioxide; D015040:Zirconium; C028541:zirconium oxide