title: Feasibility of Dental Implant Replacement in Failed Sites: A Systematic Review.
abstract: OBJECTIVE
  To assess the clinical outcomes of replaced implants after removal of failed ones. In addition, associated risk factors that might affect the final outcome of these procedures were also explored.
  
  
  METHODS
  An electronic literature search was conducted by two reviewers in several databases for articles written in English up to November 2014. Human clinical trials with a minimum of 10 subjects enrolled that reported clinical outcomes with a mean follow-up period of at least 12 months after implant replacement were included. Implant survival and nonmodifiable/modifiable factors at second and third implant placement attempts were studied. Hence, the PICO question that was aimed to be addressed was: Do patients undergoing implant replacement (second and third attempts) in previous failed sites have comparable clinical outcomes by means of implant survival/failure rate to implants placed at the first attempt?
  
  
  RESULTS
  Five retrospective clinical cohort studies and two case series satisfied the selection criteria and thus were included in this review. In total, 396 patients were studied due to implant replacement in previous failed sites. The survival rate for implant replacement at the second attempt was 88.84% (390/439; range, 71% to 94.6%) with a mean follow-up of 41.59 ± 16.77 months. Thirty-one implants were replaced for a third attempt with a mean survival rate of 74.19% (23/31) at the follow-up of 29.66 ± 14.71 months. Major risk indicators were generally divided into patient-related factors (health status, smoking habits, and oral hygiene maintenance), implant characteristics (dimensions, coating, and loading), and site characteristics (bone quality and density, vertical and horizontal dimensions, soft tissue around the implant).
  
  
  CONCLUSIONS
  Implant replacement is a reasonably feasible option for scenarios of early and late implant failure. However, modifiable risk factors must be controlled before proceeding for implant replacement.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhou
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Alberto
authors.initials: A
authors.lastname: Monje
authors.forename: Basel
authors.initials: B
authors.lastname: Elnayef
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Wu
mesh_terms: D002986:Clinical Trials as Topic; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D019232:Dental Restoration Failure; D006801:Humans; D019233:Retreatment; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis
chemical_list: D015921:Dental Implants