title: Clinical outcome of single porcelain-fused-to-zirconium dioxide crowns: a systematic review.
abstract: BACKGROUND
  The increasing demand by patients for esthetic and metal-free restorations has driven the development of ceramic restorations with good esthetic and mechanical stability. Recent clinical studies have investigated the use of zirconium dioxide as a core material for complete crowns and computer-aided-design/computer-aided-manufacturing fabricated restorations.
  
  
  OBJECTIVE
  The aim of this systematic review was to evaluate the clinical survival rates of porcelain-fused-to-zirconia (PFZ) single crowns on anterior and posterior teeth and to compare them with metal ceramic (MC) crowns.
  
  
  METHODS
  A systematic search was conducted with PubMed and manual research to identify literature written in English that refers to in vivo studies published from January 1, 1950 through July 1, 2011. Clinical trials that evaluated PFZ and MC single crowns on natural teeth were selected for further analysis. Titles and/or abstracts of articles identified through the electronic searches were reviewed and evaluated for appropriateness. In addition, a hand search of relevant dental journals was peformed, and reference lists of culled articles were screened to identify publications.
  
  
  RESULTS
  The search resulted in a total of 488 initial matches. Nineteen studies with a total of 3621 crowns met the inclusion criteria. The survival rates of PFZ crowns (total 300) ranged from 92.7% to 100% for a follow-up time of 24 to 39 months, whereas those of MC crowns (total 3321) ranged from 70% to 100% for a follow-up time of 12 to 298 months. Studies that reported long-term results were found only for the MC crown group.
  
  
  CONCLUSIONS
  The scientific clinical data available to compare PFZ and MC crowns are limited. The survival rates may well be influenced by the selection and appropriate use of the veneering ceramic, and, therefore, additional prospective long-term clinical trials are necessary to draw reliable conclusions.
authors.affiliation: Lecturer, Department of Fixed Prosthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan; and Adjunct Associate Professor, Department of Preventive and Restorative Sciences, Robert Schattner Center, University of Pennsylvania School of Dental Medicine, Philadelphia, Pa. Electronic address: takeichi@dental.upenn.edu.
authors.forename: Takuro
authors.initials: T
authors.lastname: Takeichi
authors.forename: Joannis
authors.initials: J
authors.lastname: Katsoulis
authors.forename: Markus B
authors.initials: MB
authors.lastname: Blatz
mesh_terms: D003442:Crowns; D003738:Dental Cements / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D006801:Humans; D016876:Metal Ceramic Alloys / Q000737:chemistry; D016896:Treatment Outcome; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003738:Dental Cements; D003764:Dental Materials; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide