Time Interval after Radiotherapy and Dental Implant Failure: Systematic Review of Observational Studies and Meta-Analysis

BackgroundTypically, dental implants are placed in irradiated bone after a delay that exceeds 6 months, but it is not known whether longer delays are beneficial. PurposeThe 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. Materials and MethodsFour 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. ResultsOverall, 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). ConclusionsPlacing 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.