Dental implant placement strategies in impaction-associated edentulous sites: a systematic review

Implant placement in impaction-associated edentulous sites (IAES) presents significant challenges, with various strategies proposed but no clear guidelines. This systematic review was conducted in accordance with PRISMA guidelines through a comprehensive literature search of PubMed, Scopus, and Web of Science to assess different dental implant placement strategies for IAES. Data on study and patient characteristics, management approaches, follow-up duration, implant outcomes, and complications were extracted and synthesized qualitatively. A total of 100 cases with 174 implants from 50 studies were included. Maxillary canines were the most frequently impacted teeth at implant sites (n = 76), and 26 impacted retained roots (IRRs) were identified. Cases were managed either by removing the impacted entity before implantation or by preserving it in situ. Since two cases involved both management approaches, the strategy-level classification included 47 extraction-based and 55 preservation-based entries. Of the 93 implants in the extraction group, equal implant success and survival rates of 98.92% were observed, with a mean follow-up duration of 25.7 ± 24.1 months. Among 81 implants in the non-extraction group, implant success and survival rates were 85.18% and 92.59%, respectively, with a mean follow-up duration of 53.0 ± 34.2 months. Overall, nearly all reported implant-related complications occurred in cases where implants contacted the impacted structure, predominantly in IRRs. Implant placement in IAES may be associated with favorable outcomes when direct contact with impacted structures is avoided. In contrast, implant-impacted entity contacts may pose a higher risk of complications. However, given the substantial heterogeneity among the included studies and lack of controlled designs, the observed differences between these two approaches should be interpreted descriptively rather than as comparative evidence. Based on the limited available low-level evidence, implant placement through impacted structures remains a novel yet high-risk approach that requires further validation.