title: Evaluation of zirconium-oxide-based ceramic single-unit posterior fixed dental prostheses (FDPs) generated with two CAD/CAM systems compared to porcelain-fused-to-metal single-unit posterior FDPs: a 5-year clinical prospective study.
abstract: OBJECTIVE
  The purpose of this prospective clinical study was to determine the success rate of single-unit posterior fixed dental prostheses (FDPs) with zirconia copings generated with two CAD/CAM systems, compared to porcelain-fused-to-metal (PFM) single-unit posterior FDPs after 5 years of function.
  
  
  METHODS
  From 2005 to 2006, 60 patients who needed a single-unit FDP on a first molar in the mandibular jaw (left or right) in a private office setting were included in this study. The 60 first mandibular molars were randomly divided into three groups (n = 20): in the control group (group C), 20 PFM FDPs were included. In the other two groups CAD/CAM technology was used for the fabrication of the zirconium-oxide copings: 20 single-unit posterior FDPs with zirconia copings were generated with the Procera system (group P, Nobel Biocare); 20 single-unit posterior FDPs with zirconia copings were generated with the Lava system (group L, 3M ESPE). For the ANOVA follow-up data, the clinical life table method was applied. The statistical analysis was performed using two nonparametric tests, the log-rank test for k-groups and the Fisher exact test.
  
  
  RESULTS
  No statistically significant difference in the clinical outcome of zirconia-ceramic FDPs of both groups (P and L) evaluated together and metal-ceramic posterior single FDPs was found at 5 years of function; however, clinical data showed that technical problems, such as extended fracture of the veneering ceramic, tended to occur more frequently in the zirconia-ceramic FDP groups. The difference in the frequency of failure was statistically significant only in the comparison of groups C and P.
  
  
  CONCLUSIONS
  Even if no statistically significant difference in the clinical outcome of zirconia-ceramic FDPs of both groups (P and L) considered together and metal-ceramic posterior single FDPs was found at 5 years of function, clinical data showed that the two zirconia-ceramic FDP groups tended to have more frequent clinical problems: for this reason all the clinical and technical variables related to the use of zirconia-ceramic FDPs generated with CAD/CAM systems should be carefully considered prior to all treatment procedures.
authors.affiliation: Department of Clinical Odontostomatology, University of Padova, Institute of Clinical Dentistry, Padova, Italy. paolovigolo@virgilio.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Vigolo
authors.forename: Sabrina
authors.initials: S
authors.lastname: Mutinelli
mesh_terms: D000328:Adult; D002484:Cementation / Q000379:methods; D017076:Computer-Aided Design; D003442:Crowns; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D019554:Dental Restoration Wear; D003801:Dental Veneers; D005500:Follow-Up Studies; D005899:Glass Ionomer Cements / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008875:Middle Aged; D011446:Prospective Studies; D013499:Surface Properties; D016019:Survival Analysis; D014025:Titanium / Q000737:chemistry; D016896:Treatment Outcome; D055815:Young Adult; D015040:Zirconium / Q000737:chemistry*
chemical_list: D005899:Glass Ionomer Cements; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; C077451:Procera; D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide