Endodontic treatment of dens invaginatus type III with three root canals and open apical foramen

Aim To describe the conservative endodontic treatment and the 1-year follow-up of a permanent maxillary lateral incisor with dens invaginatus. Summary Frequently, the root canal treatment of invaginated teeth is challenging because of problems associated with gaining access to the root canals and with variations of canal morphology associated with this type of malformation. The present case describes the complex root canal treatment of dens invaginatus in a maxillary lateral incisor with three root canals (Oehler type III), incomplete apex formation, necrotic pulp and abscess formation. After gaining access to two root canals and the invagination with the help of a dental operating-microscope, the canals and the invagination were instrumented and calcium hydroxide dressing was applied for 6 months. Apexification and osseous bone repair were achieved, and the canals were filled with gutta-percha. A follow-up after 1 year showed that the tooth was free of any clinical symptoms and the periapical condition was normal. Key learning points The present case demonstrates that conservative root canal treatment can be performed successfully even in severe cases of dens invaginatus. The use of a dental operating microscope can help in the management of complicated cases of invaginated teeth through conventional root canal treatment.