Microbial control and a simple regenerative endodontic protocol achieve durable apical healing and long-term root development: a 10-year case report

Regenerative endodontics offers a biologically driven alternative to apexification for immature teeth with necrotic pulps and apical periodontitis. We report the management of an 11-year-old girl with a history of dentoalveolar trauma and an immature maxillary left central incisor (tooth 21) presenting with gray discoloration, negative sensibility, and a defined apical radiolucency (Nolla stage 9). Treatment followed a conservative, accessible protocol: disinfection with 5.25% sodium hypochlorite, placement of triple-antibiotic paste (ciprofloxacin, metronidazole, amoxicillin), and, at two weeks, irrigation with 17% EDTA, apical bleeding induction by controlled over-instrumentation, placement of a collagen matrix, and sealing with white mineral trioxide aggregate under a definitive composite restoration. A separate endodontic treatment was later performed on tooth 11 for mastication pain unrelated to the regenerative site. Long-term follow-up showed progressive and stable tissue regeneration. At 4 years, periapical radiography revealed early hard-tissue deposition in the middle and apical thirds and a slight increase in root length. At 8 years, marked root elongation and dentinal wall thickening were evident, improving structural prognosis. Cone-beam CT at 10 years confirmed complete apical closure, absence of periapical pathology, and substantial thickening of canal walls. Clinically, periodontal health remained intact and the tooth recovered a positive response to cold testing, consistent with true pulpal regeneration. This case demonstrates that meticulous microbial control combined with a simple, cost-conscious regenerative protocol may be associated with durable apical healing, continued root development, and functional recovery in an immature traumatized incisor. Although this is a single case and the findings are not generalizable, the sustained radiographic and clinical outcomes over a decade suggest that regenerative endodontics can be a feasible option in selected comparable cases when performed under appropriate clinical conditions.