Background: Dens invaginatus (DI) is a developmental dental anomaly whose clinical manifestations and treatment plans vary depending on its type and severity. Type III DI is one of the primary pathways of periradicular infection. This report presents a series of cases of endodontic treatment of type III DI with periradicular lesions in young permanent teeth. Cases: Four cases with type III coronal DI (CDI) and periradicular lesions were included. Following oral and radiographic examinations, the patients underwent endodontic treatment. Among them, three cases accepted endodontic access to invaginations, chemomechanical instrumentation, medication, obturation, and periodontal surgical procedures when clinically indicated. The other patient also underwent main root canal treatment simultaneously. After long-term follow-up (1–3 years), all patients were free of clinical symptoms or positive clinical signs, with evidence of reduced or resolved periapical radiolucency and normal pulp vitality. Conclusions: By disinfecting and obturating the invagination canal, the pulp vitality of the affected type III CDI tooth can be preserved with minimal damage to the tooth structure, thereby promoting further root development in young permanent teeth.
A 2026 study studied this question.