Abstract
The efficacy of nano-hydroxyapatite (nHA) alone and in combination with platelet-rich fibrin (PRF) in enhancing periapical bone healing following endodontic retreatment is of interest. Thirty-two patients with failed endodontic treatment in anterior teeth were divided into two groups. After retreatment, apicoectomy and root-end filling with mineral trioxide aggregate (MTA) were performed. Group 1 received nHA alone, while Group 2 received a combination of nHA and PRF in the periapical cavity. Follow-ups at 1, 3, and 6 months showed significant lesion size reduction in both groups, with faster healing in the nHA+PRF group at 1 month, but no long-term differences.