title: A retrospective survey on long-term survival of posterior zirconia and porcelain-fused-to-metal crowns in private practice.
abstract: OBJECTIVE
  This retrospective survey assessed the clinical survival of zirconia-based crowns (PFZ) and conventional porcelain- fused-to-metal (PFM) crowns on posterior teeth in private practice.
  
  
  METHODS
  A print survey of 13 private practitioners was conducted to assess the long-term survival of previously placed full-coverage crowns. The practitioners reported a total of 2,182 premolar (n = 881) and molar (n = 1,301) full-coverage single crowns, 1,102 PFZ and 1,080 PFM, fabricated by one dental laboratory (Cusp, Boston) and followed over 7.4 years. All post-cementation complications (eg, porcelain fractures and chippings) were recorded as failures. In the PFZ group, one veneering porcelain (CZR, Kuraray Noritake) was used in combination with three coping systems (Lava, 3M ESPE; Procera, Nobelbiocare; Katana, Kuraray Noritake). Kaplan-Meier survival analysis was used for statistical analyses.
  
  
  RESULTS
  The probability of survival of posterior crowns investigated over the period of study (7.4 years) was 99.3% for PFM and 99.2% for PFZ restorations. There was no statistically significant difference (P = .614) between PFZ and PFM groups. In the PFZ group, probability of survival was 97.7% for Lava, 100% for Procera, and 99.5% for Katana. There were no statistically significant differences (P = .34) between the three PFZ systems or the location of the crowns (premolar or molar; P = .454).
  
  
  CONCLUSIONS
  PFZ crowns fabricated with CZR and three commercial zirconia coping systems revealed excellent long-term success rates. Survival times and survival probabilities of posterior PFZ crowns did not differ from PFM crowns and were independent of type of coping system and location (molar or premolar teeth).
authors.forename: Fusun
authors.initials: F
authors.lastname: Ozer
authors.forename: Francis K
authors.initials: FK
authors.lastname: Mante
authors.forename: Gerard
authors.initials: G
authors.lastname: Chiche
authors.forename: Najeed
authors.initials: N
authors.lastname: Saleh
authors.forename: Takuro
authors.initials: T
authors.lastname: Takeichi
authors.forename: Markus B
authors.initials: MB
authors.lastname: Blatz
mesh_terms: D003442:Crowns; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D006801:Humans; D016876:Metal Ceramic Alloys; D012189:Retrospective Studies; D015040:Zirconium
chemical_list: D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D015040:Zirconium