title: Complication and failure rates with implant-supported fixed dental prostheses and single crowns: a 10-year retrospective study.
abstract: OBJECTIVE
  Clinical studies related to the long-term outcomes with implant-supported reconstructions are still sparse. The aim of this 10-year retrospective study was to assess the rate of mechanical/technical complications and failures with implant supported fixed dental prostheses (FDPs) and single crowns (SCs) in a large cohort of partially edentulous patients.
  
  
  METHODS
  The comprehensive multidisciplinary examination consisted of a medical/dental history, clinical examination, and a radiographic analysis. Prosthodontic examination evaluated the implant-supported reconstructions for mechanical/technical complications and failures, occlusal analysis, presence/absence of attrition, and location, extension, and retention type.
  
  
  RESULTS
  Out of three hundred ninety seven fixed reconstructions in three hundred three patients, two hundred sixty eight were SCs and one hundred twenty seven were FDPs. Of these three hundred ninety seven implant-supported reconstructions, 18 had failed, yielding a failure rate of 4.5% and a survival rate of 95.5% after a mean observation period of 10.75 years (range: 8.4-13.5 years). The most frequent complication was ceramic chipping (20.31%) followed by occlusal screw loosening (2.57%) and loss of retention (2.06%). No occlusal screw fracture, one abutment loosening, and two abutment fractures were noted. This resulted in a total mechanical/technical complication rate of 24.7%. The prosthetic success rate over a mean follow-up time of 10.75 years was 70.8%. Generalized attrition and FDPs were associated with statistically significantly higher rates of ceramic fractures when compared with SCs. Cantilever extensions, screw retention, anterior versus posterior, and gender did not influence the chipping rate.
  
  
  CONCLUSIONS
  After a mean exposure time of 10.75 years, high survival rates for reconstructions supported by Sand-blasted Large-grit Acid-etched implants can be expected. Ceramic chipping was the most frequent complication and was increased in dentitions with attrition and in FDPs compared with SCs.
authors.affiliation: Division of Fixed Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Julia-Gabriela
authors.initials: JG
authors.lastname: Wittneben
authors.forename: Daniel
authors.initials: D
authors.lastname: Buser
authors.forename: Giovanni E
authors.initials: GE
authors.lastname: Salvi
authors.forename: Walter
authors.initials: W
authors.lastname: Bürgin
authors.forename: Stefan
authors.initials: S
authors.lastname: Hicklin
authors.forename: Urs
authors.initials: U
authors.lastname: Brägger
mesh_terms: D003442:Crowns; D015921:Dental Implants; D005260:Female; D006801:Humans; D008297:Male; D011475:Prosthesis Failure; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D015921:Dental Implants
keywords: dental implant; fixed dental implant supported prosthesis; mechanical complication; prosthesis failure; prosthesis survival; single implant crown; technical complication