Risk Factors for Failure of Separated Instrument Removal: A Systematic Review and Meta‐Analysis

This study aimed to systematically evaluate the risk factors associated with the failure of separated instrument removal. A comprehensive search of PubMed, Embase and the Cochrane Library was performed to identify studies reporting on the success rates of separated instrument removal, covering the period from 1988 to 2025. The meta-analysis was performed using Stata 17.0. Seven studies encompassing 922 patients with separated instruments were included. The pooled success rate of separated instrument removal was 66%. Meta-analysis identified several significant risk factors for removal failure: instrument location in posterior teeth, mandibular teeth, the apical third of the canal, the apical side of a curved canal, and root curvature exceeding 30°. Current evidence indicates that unfavourable anatomical factors significantly increase the likelihood of failed instrument retrieval. These findings underscore the importance of preoperative assessment and careful case selection when planning separated instrument removal procedures.