Prior Endodontic Therapy as a Risk Factor for Implant Failure

OBJECTIVE: Multiple clinical reports suggest that the risk of implant failure is higher at sites or proximal to teeth/sites with a history of endodontic therapy. The purpose of this retrospective analysis was to characterize implant failures with respect to prior endodontic therapy. METHODS: IRB approval was obtained to review the records of all patients identified with failed implants placed in the post-graduate periodontics clinic at the University of Maryland from 2000 to 2006. A retrospective survey of records was performed to identify and determine the characteristics of implant failures, including prior dental history and time to implant failure. Data were submitted to Chi-square analysis. RESULTS: A total of 77 consecutive implant failures were identified in 55 patients (49 to 73 years of age; 37 Caucasian; 15 African-American; 3 Asian). Treatment history was unavailable for 3 implant failures, which were excluded from the analysis. None of the implants were placed in immediate function. Of the implant failures, 50.8% were placed at sites (33.8%) or proximal to teeth/sites (16.9%) with a history of endodontic therapy. A significantly higher proportion (p ≤ 0.05) of early implant failures (< 12 months) were placed at sites or proximal to teeth/sites with a history of endodontic therapy than those without prior root canal therapy (26% versus 7.7%, respectively). CONCLUSIONS: Implant failures were equally distributed among sites with and without prior endodontic therapy; however, sites with prior endodontic therapy were disproportionately associated with earlier implant failure than sites without previous root canal treatment.