title: A 5-year retrospective study of survival of zirconia single crowns fitted in a private clinical setting.
abstract: OBJECTIVE
  The aim of this report was to evaluate the 5-year clinical performance and survival of zirconia (NobelProcera™) single crowns.
  
  
  METHODS
  All patients treated with porcelain-veneered zirconia single crowns in a private practice during the period October 2004 to November 2005 were included. The records were scrutinized for clinical data. Information was available for 162 patients and 205 crowns.
  
  
  RESULTS
  Most crowns (78%) were placed on premolars and molars. Out of the 143 crowns that were followed for 5 years, 126 (88%) did not have any complications. Of those with complications, the most common were: extraction of abutment tooth (7; 3%), loss of retention (15; 7%), need of endodontic treatment (9; 4%) and porcelain veneer fracture (6; 3%). No zirconia cores fractured. In total 19 restorations (9%) were recorded as failures: abutment tooth extraction (7), remake of crown due to lost retention (6), veneer fracture (4), persistent pain (1) and caries (1). The 5-year cumulative survival rate (CSR) was 88.8%.
  
  
  CONCLUSIONS
  According to the present 5-year results zirconia crowns (NobelProcera™) are a promising prosthodontic alternative also in the premolar and molar regions. Out of the 143 crowns followed for 5 years, 126 (88%) did not have any complications. However, 9% of the restorations were judged as failures. Further studies are necessary to evaluate the long-term success.
authors.affiliation: Department Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden. anders.ortorp@odontologi.gu.se
authors.forename: Anders
authors.initials: A
authors.lastname: Ortorp
authors.forename: Maria Lind
authors.initials: ML
authors.lastname: Kihl
authors.forename: Gunnar E
authors.initials: GE
authors.lastname: Carlsson
mesh_terms: D001641:Bicuspid / Q000473:pathology; D003442:Crowns; D000044:Dental Abutments; D003731:Dental Caries / Q000628:therapy; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019232:Dental Restoration Failure; D003801:Dental Veneers; D005500:Follow-Up Studies; D006801:Humans; D008963:Molar / Q000473:pathology; D019279:Resin Cements / Q000737:chemistry; D012189:Retrospective Studies; D012390:Root Canal Therapy; D016019:Survival Analysis; D014081:Tooth Extraction; D016896:Treatment Outcome; D015036:Zinc Phosphate Cement / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; C483701:Rely X Unicem; D019279:Resin Cements; D003776:Dental Porcelain; D015036:Zinc Phosphate Cement; D015040:Zirconium; C028541:zirconium oxide