title: Comparative reliability analyses of zirconium oxide and lithium disilicate restorations in vitro and in vivo.
abstract: BACKGROUND
  The authors analyzed the in vitro and in vivo performance of lithium disilicate glass-ceramic (LDGC) restorations and yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) (that is, zirconium oxide) restorations with regard to reliability, clinical performance and abrasion resistance.
  
  
  METHODS
  In the in vitro study, four authors subjected samples of LDGC, Y-TZP and metal-ceramic crowns to step-stress fatigue testing. Four investigators assessed the in vivo clinical performance of LDGC and zirconium oxide-based restorations at four and seven years, respectively. In addition, one author conducted a randomized, controlled clinical trial to analyze the volumetric loss of enamel and ceramic antagonist surfaces.
  
  
  RESULTS
  The LDGC crowns exhibited the highest fatigue load-to-failure values in the in vitro analysis. The results of the in vivo assessment showed that the clinical performance of the LDGC restorations at four years was comparable to that of the zirconium oxide-based crowns at seven years. The results of the in vivo, randomized, controlled clinical trial showed that LDGC crowns were not only resistant to wear, but also were wear friendly to enamel antagonist surfaces.
  
  
  CONCLUSIONS
  The LDGC crowns in the in vitro and in vivo studies exhibited high durability, and they were wear friendly to opposing natural dentition.
  
  
  CONCLUSIONS
  LDGC and zirconium oxide-based crowns are a clinically acceptable means of treating teeth that require full-coverage restorations. In addition, LDGC materials exhibit excellent clinical performance, as well as demonstrate acceptable abrasion compatibility with the opposing natural dentition.
authors: Department of Prosthodontics, New York University College of Dentistry, New York City, NY, USA.
authors: Nelson R F A
authors: NR
authors: Silva
authors: Van P
authors: VP
authors: Thompson
authors: Guiherme Bonecker
authors: GB
authors: Valverde
authors: Paulo G
authors: PG
authors: Coelho
authors: John M
authors: JM
authors: Powers
authors: John W
authors: JW
authors: Farah
authors: Josephine
authors: J
authors: Esquivel-Upshaw
mesh_terms: D000328:Adult; D002516:Ceramics / Q000737:chemistry; D017076:Computer-Aided Design; D003442:Crowns; D000044:Dental Abutments; D003743:Dental Enamel / Q000473:pathology; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D017266:Dental Prosthesis; D019232:Dental Restoration Failure; D019554:Dental Restoration Wear; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D003830:Denture, Partial, Fixed; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008422:Materials Testing / Q000379:methods; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D013314:Stress, Mechanical; D014072:Tooth Abrasion / Q000209:etiology; D055815:Young Adult; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D016876:Metal Ceramic Alloys; C493120:lithia disilicate; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; C023506:Glass ceramics; D015040:Zirconium; C028541:zirconium oxide