title: Prospective evaluation of zirconia based tooth- and implant-supported fixed dental prostheses: 3-year results.
abstract: OBJECTIVE
  This prospective clinical study compared the performance of implant-retained (study group) and tooth-retained (control) zirconia based fixed dental prostheses (FDPs) with at least 4 units. The null-hypothesis stated that complication rates in both groups are equally distributed.
  
  
  METHODS
  The study included patients in need of one 4- to 6-unit implant- or tooth-retained FDP each. All patients were examined 2 weeks after insertion (baseline) and then at 6 month intervals up to 3 years. At follow-up all restorations were examined for framework fracture, chipping, marginal integrity, surface roughness and biological complications. Kaplan-Meier estimation was used for data analysis.
  
  
  RESULTS
  20 patients received tooth-retained and 7 patients implant-retained FDPs. The study was halted early when differences in chipping rates reached a statistically significant level. One FDP in the study group was lost due to implant abutment failure. FDP related chipping rates were 71% in the study group (mean observation time 32 months) and 15% in the control (mean observation time 34 months). Unit (abutment crown/pontic) related chipping rates were 32% in the study group and 6% in the control. Chipping rates differed statistically significant (log-rank test, p<.05). However, all ceramic defects could be corrected by grinding and polishing. No framework fracture was detected.
  
  
  CONCLUSIONS
  Within the study limitations, survival rates seem satisfactorily in both implant- and tooth retained long-span zirconia based FDPs. However, implant-supported FDPs seem more susceptible to veneering ceramic chippings.
  
  
  CONCLUSIONS
  The high chipping rates found in this study discourage the use of long-span implant-retained FDPs with zirconia frameworks. The study was registered in ClinicalTrials.gov with the ID Number NCT02220764.
authors.affiliation: Department of Prosthodontics, Dental School of Dresden, Fetscherstr. 74, 01307, Germany. Electronic address: Ioannis.Konstantinidis@uniklinikum-dresden.de.
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Konstantinidis
authors.affiliation: Department of Prosthodontics, Dental School of Dresden, Fetscherstr. 74, 01307, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Jacoby
authors.affiliation: Department of Prosthodontics, Dental School of Dresden, Fetscherstr. 74, 01307, Germany. Electronic address: Michael.Raedel@uniklinikum-dresden.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Rädel
authors.affiliation: Department of Prosthodontics, Dental School of Dresden, Fetscherstr. 74, 01307, Germany. Electronic address: Klaus.Boening@uniklinikum-dresden.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Böning
mesh_terms: D000328:Adult; D000368:Aged; D002516:Ceramics; D015921:Dental Implants / Q000009:adverse effects*; D003776:Dental Porcelain / Q000627:therapeutic use; D019232:Dental Restoration Failure; D003779:Denture Design; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014070:Tooth / Q000473:pathology / Q000601:surgery; D016388:Tooth Loss / Q000473:pathology / Q000601:surgery*; D015040:Zirconium / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D015921:Dental Implants; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide
keywords: Ceramics; Chipping; Fracture resistance; Prospective study; Survival rate; Zirconia