title: Survival of dental implants placed in sites of previously failed implants.
abstract: OBJECTIVE
  To assess the survival of dental implants placed in sites of previously failed implants and to explore the possible factors that might affect the outcome of this reimplantation procedure.
  
  
  METHODS
  Patients that had failed dental implants, which were replaced with the same implant type at the same site, were included. Descriptive statistics were used to describe the patients and implants; survival analysis was also performed. The effect of systemic, environmental, and local factors on the survival of the reoperated implants was evaluated.
  
  
  RESULTS
  175 of 10,096 implants in 98 patients were replaced by another implant at the same location (159, 14, and 2 implants at second, third, and fourth surgeries, respectively). Newly replaced implants were generally of similar diameter but of shorter length compared to the previously placed fixtures. A statistically significant greater percentage of lost implants were placed in sites with low bone quantity. There was a statistically significant difference (P = 0.032) in the survival rates between implants that were inserted for the first time (94%) and implants that replaced the ones lost (73%). There was a statistically higher failure rate of the reoperated implants for patients taking antidepressants and antithrombotic agents.
  
  
  CONCLUSIONS
  Dental implants replacing failed implants had lower survival rates than the rates reported for the previous attempts of implant placement. It is suggested that a site-specific negative effect may possibly be associated with this phenomenon, as well as the intake of antidepressants and antithrombotic agents.
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors.forename: Bruno R
authors.identifier: http://orcid.org/0000-0002-3460-3374
authors.initials: BR
authors.lastname: Chrcanovic
authors.affiliation: Clinic for Prosthodontics, Centre of Dental Specialist Care, Malmö, Sweden.
authors.forename: Jenö
authors.initials: J
authors.lastname: Kisch
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.|Department of Biomaterials, Göteborg University, Göteborg, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Albrektsson
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors.forename: Ann
authors.initials: A
authors.lastname: Wennerberg
mesh_terms: D003758:Dental Implantation, Endosseous / Q000009:adverse effects / Q000379:methods; D015921:Dental Implants / Q000009:adverse effects; D019232:Dental Restoration Failure / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012086:Reoperation / Q000009:adverse effects* / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants
keywords: dental implants; implant failure; reimplantation; survival rate