title: Time interval after radiotherapy and dental implant failure: systematic review of observational studies and meta-analysis.
abstract: BACKGROUND
  Typically, dental implants are placed in irradiated bone after a delay that exceeds 6 months, but it is not known whether longer delays are beneficial.
  
  
  OBJECTIVE
  The purpose of the study is to review the literature comparing the failure rate of dental implants placed in irradiated bone between 6 and 12 months and after 12 months from the cessation of radiotherapy.
  
  
  METHODS
  Four electronic databases were searched for articles published until February 2013 without language restriction: Lilacs, Medline, Scopus, and the Cochrane Central Register of Controlled Trials. Two reviewers independently assessed the eligibility criteria and extracted data. Fixed effect meta-analysis was performed.
  
  
  RESULTS
  Overall, 3,749 observational studies were identified. After the screening of titles and abstracts, 236 publications were selected, and 10 were included in the final analysis. The pooled relative risk (RR) of failure was RRpooled  = 1.34 (95% confidence interval [CI]: 1.01-1.79), higher in individuals who had dental implants installed between 6 and 12 months after receiving radiotherapy. I(2) indicated nearly 21% heterogeneity (p = .25). Egger's test indicated no evidence of publication bias (p = .62); however, the removal of one study significantly affected the overall RR (RRpooled  = 1.08, 95% CI: 0.77-1.52).
  
  
  CONCLUSIONS
  Placing implants in bone within a period shorter than 12 months after radiotherapy may result in a higher risk of failure; however, additional evidence from clinical trials is needed to verify this risk.
authors.affiliation: Graduate Program in Dentistry, School of Dentistry, Universidade Luterana do Brasil, Campus Canoas (ULBRA), Canoas, RS, Brazil.
authors.forename: Matheus Piardi
authors.initials: MP
authors.lastname: Claudy
authors.forename: Sergio Augusto Quevedo
authors.initials: SA
authors.lastname: Miguens
authors.forename: Roger Keller
authors.initials: RK
authors.lastname: Celeste
authors.forename: Raphael
authors.initials: R
authors.lastname: Camara Parente
authors.forename: Pedro Antonio González
authors.initials: PA
authors.lastname: Hernandez
authors.forename: Aurelício Novaes
authors.initials: AN
authors.lastname: da Silva
mesh_terms: D000539:Alveolar Process / Q000528:radiation effects* / Q000601:surgery*; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D019232:Dental Restoration Failure; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans
chemical_list: D015921:Dental Implants
keywords: dental implants; meta-analysis; osseointegration; osteoradionecrosis; radiotherapy