Aim: This paper highlights a novel method of apical plug formation with a successful outcome. Methods: Clinical examination of the left maxillary central incisor revealed a draining intraoral sinus in the labial vestibule. A radiograph of the tooth 21 showed an obturated root canal with the presence of incomplete root formation and periapical radiolucency. The endodontic retreatment of tooth 21 was carried out under rubber dam isolation. Hydroxyapatite was condensed into the periapical bone defect along with obturation of the apical third of the root canal. The remaining canal space was obturated with thermoplasticised gutta-percha and the access preparation was restored using resin composite. Result: The 1 year-recall radiograph of the patient revealed a successful outcome and the patient was asymptomatic. Conclusion: Condensation of hydroxyapatite into the periapical bone defect, along with biomimetic obturation using hydroxyapatite of the apical root canal system is an innovative approach for the nonsurgical treatment of cases with incomplete root formation. Schlagwörter: apexification, calcium hydroxide, hydroxyapatite, root canal therapy