Rapid Radiographic Healing in a Failed Tooth #36 with Large Periapical and Furcation Lesion Following Retreatment Using nRoot Bioceramic Sealer: A 7‑Month Case Report.

ABSTRACT Background: Large periapical and bifurcation lesions in failed endodontic cases pose significant challenges for regenerative healing. Case Presentation: A 44‑year‑old medically free female presented with intermittent pain, exudate, and odour from the lower left (#36). Clinical and radiographic evaluation revealed a previously treated tooth with chronic periapical abscess, large periapical radiolucency, and complete loss of bifurcation bone. Retreatment was performed using rotary instrumentation to 25/.06, calcium hydroxide medication, sonic-assisted irrigants, and obturation with nRoot bioceramic sealer via single-cone technique. Restoration with fiber-reinforced composite followed. At 7‑month follow‑up, rapid bone regeneration was observed, including bifurcation area; radiopaque sealer residues evident. Conclusion: nRoot (ENP Biotechnology) shows promising bioactivity and radiopacity, fostering rapid healing in complex lesions. Further studies are warranted.