What Is the Role of Endodontic Predisposing Factors in Early Implant Failure?

We aimed to investigate a possible relationship between early implant failure (EIF) and an adjacent root canal–treated tooth and/or tooth with a periapical lesion (PL), considering the duration between implantation and root canal treatment (RCT). The importance of prior RCT and/or presence of a PL before implantation was also investigated. A total of 810 implants from 342 patients were included and scored according to the implant failure before abutment connection, adjacent root canal treated teeth, adjacent teeth without RCT, no adjacent teeth, adjacent teeth with PL, extraction of teeth with PL, and/or RCT before implantation. The durations between the extraction and implantation and between RCT and implantation adjacent to the root canal–treated teeth were recorded. The time from the RCT of adjacent teeth to implant placement was categorized into 5 groups: less than 4 weeks before implantation, 4–12 weeks before implantation, at least 12 weeks before implantation, within 4 weeks after implantation, and at least 4 weeks after implantation. Among the endodontic predictors, a prior PL on the tooth extracted was associated with an increased risk of EIF (P < .05, odds ratio: 4.37; 95% confidence interval: 1.604–11.891). Furthermore, EIF was more likely to occur when the RCT of an adjacent tooth was performed within 4 weeks of implantation (P < .05). Additional investigations with larger sample sizes are necessary to validate our findings.