title: Prospective clinical study of zirconia posterior fixed partial dentures: 3-year follow-up.
abstract: OBJECTIVE
  The purpose of this prospective clinical cohort study was to determine the success rate of 3- to 5-unit posterior fixed partial dentures (FPDs) with zirconia frameworks after 3 years of function.
  
  
  METHODS
  Forty-five patients in need of at least 1 FPD to replace 1 to 3 posterior teeth were included. The frameworks were produced by means of a prototype computer-assisted manufacture system. They were milled with a precisely calculated increase in size out of presintered zirconia blanks and subsequently shrunk to the required size. Fifty-seven FPDs were cemented using either Variolink or Panavia TC cement. Clinical and radiographic examinations were performed at baseline, 12, 24, and 36 months after cementation. Statistical analysis was performed by descriptive statistics and the Kaplan-Meier survival analysis. Comparisons of probing depth, Plaque Index, and bleeding on probing between test (abutment) and control (contralateral) teeth were done with the McNemar test.
  
  
  RESULTS
  Thirty-six patients with 46 FPDs were available for examination after 36 months. No fractures occurred, rendering a 100% success rate of the zirconia frameworks. Seven FPDs had to be replaced because of biologic and technical problems. The survival rate, therefore, was 84.8%. Secondary caries was found in 10.9% of the FPDs, and chipping of the veneering ceramic was found in 13.0%. There were no significant differences regarding the probing depth in test and control teeth.
  
  
  CONCLUSIONS
  Zirconia frameworks demonstrated sufficient stability for replacement of posterior teeth. However, the high rates of technical problems should be reduced by further developments of the prototype processing technology.
authors.affiliation: Clinic for Fixed and Removable Prosthodontics and Dental Materials, School of Dentistry, University of Zurich, Switzerland. irena.sailer@zzmk.unizh.ch
authors.forename: Irena
authors.initials: I
authors.lastname: Sailer
authors.forename: Aurel
authors.initials: A
authors.lastname: Fehér
authors.forename: Frank
authors.initials: F
authors.lastname: Filser
authors.forename: Heinz
authors.initials: H
authors.lastname: Lüthy
authors.forename: Ludwig J
authors.initials: LJ
authors.lastname: Gauckler
authors.forename: Peter
authors.initials: P
authors.lastname: Schärer
authors.forename: Christoph Hans
authors.initials: CH
authors.lastname: Franz Hämmerle
mesh_terms: D002484:Cementation; D015331:Cohort Studies; D017076:Computer-Aided Design; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003830:Denture, Partial, Fixed; D005260:Female; D006801:Humans; D008297:Male; D008963:Molar; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D015040:Zirconium
chemical_list: D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide