Aim: The present report describes the endodontic treatment of an immature maxillary central incisor with an open apex and extensive periapical lesion. Summary: Cone-beam computed tomographic images demonstrated the unusual root canal anatomy and a contemporary approach using bioceramic intracanal dressing, root repair materials and root canal sealers were used. One year after the end of treatment, the patient was asymptomatic and a new cone-beam computed tomographic exam showed complete apical repair, with deposition of mineralized tissue and closure of the root apex. The combination of modern imaging and the use of contemporary materials contributed to adequate diagnosis, planning and treatment of this case. Key-learning points • Immature permanent teeth with apical periodontitis represent a clinical challenge. • Calcium silicate-based materials are widely used in endodontics, mainly due to their excellent biological and physical properties. • The association of different type of calcium silicate-based materials could be a good option of the treatment of immature permanent teeth with apical periodontitis.