title: Five-year clinical results of zirconia frameworks for posterior fixed partial dentures.
abstract: OBJECTIVE
  The aim of this prospective clinical cohort study was to determine the success rate of 3- to 5-unit zirconia frameworks for posterior fixed partial dentures (FPDs) after 5 years of clinical observation.
  
  
  METHODS
  Forty-five patients who needed at least 1 FPD to replace 1 to 3 posterior teeth were included in the study. Fifty-seven 3- to 5-unit FPDs with zirconia frameworks were cemented with 1 of 2 resin cements (Variolink or Panavia TC). The following parameters were evaluated at baseline, after 6 months, and 1 to 5 years after cementation at test (abutments) and control (contralateral) teeth: probing pocket depth, probing attachment level, Plaque Index, bleeding on probing, and tooth vitality. Intraoral radiographs of the FPDs were taken. Statistical analysis was performed using descriptive statistics, Kaplan-Meier survival analysis, and the McNemar test.
  
  
  RESULTS
  Twenty-seven patients with 33 zirconia FPDs were examined after a mean observation period of 53.4 +/- 13 months. Eleven patients with 17 FPDs were lost to follow-up. After the 3-year recall visit, 7 FPDs in 7 patients were replaced because they were not clinically acceptable due to biologic or technical complications. After 5 years of clinical observation, 12 FPDs in 12 patients had to be replaced. One 5-unit FPD fractured as a result of trauma after 38 months. The success rate of the zirconia frameworks was 97.8%; however, the survival rate was 73.9% due to other complications. Secondary caries was found in 21.7% of the FPDs, and chipping of the veneering ceramic in 15.2%. There were no significant differences between the periodontal parameters of the test and control teeth.
  
  
  CONCLUSIONS
  Zirconia offers sufficient stability as a framework material for 3- and 4-unit posterior FPDs. The fit of the frameworks and veneering ceramics, however, should be improved.
authors: Clinic for Fixed and Removable Prosthodontics and Dental Materials, School of Dentistry, University of Zürich, Plattenstr. 11, 8032 Zürich, Switzerland. irena.sailer@zzmk.unizh.ch
authors: Irena
authors: I
authors: Sailer
authors: Aurel
authors: A
authors: Fehér
authors: Frank
authors: F
authors: Filser
authors: Ludwig J
authors: LJ
authors: Gauckler
authors: Heinz
authors: H
authors: Lüthy
authors: Christoph Hans Franz
authors: CH
authors: Hämmerle
mesh_terms: D002484:Cementation; D015331:Cohort Studies; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry*; D003731:Dental Caries / Q000145:classification; D003774:Dental Plaque Index; D019232:Dental Restoration Failure; D003801:Dental Veneers; D003779:Denture Design; D003830:Denture, Partial, Fixed; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008689:Methacrylates / Q000737:chemistry; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000145:classification; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000145:classification; D011446:Prospective Studies; D019279:Resin Cements / Q000737:chemistry; D016896:Treatment Outcome; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003722:Dental Alloys; D008689:Methacrylates; D019279:Resin Cements; C091744:Panavia TC; C103502:Variolink; D015040:Zirconium; C028541:zirconium oxide