Non-surgical root canal treatment of dens invaginatus type 2 in a maxillary lateral incisor

The working lengths were established and recorded. The radiograph revealed a region of root resorption, with a lateral root perforation on the mesial surface. The invagination appeared to be calcified. There did not appear to be any communication between the primary root canal and the invagination. The canal system was debrided thoroughly and prepared by the step-back technique to a size 40. Copious irrigation with 2.6% sodium hypochlorite solution was used throughout the procedure. After drying the root canals with paper points, a cotton pellet was placed in the pulp chamber and the tooth was temporarily sealed with Cavit (ESPE, Seefeld, Germany). One week later, the patient returned without symptoms and the swelling had disappeared. The invagination was obturated by lateral condensation of gutta-percha and zinc oxide-eugenol sealer (Canals, Showa Yakuhin, Tokyo, Japan). The primary root canal was dried and filled with calcium hydroxide paste. Cotton wool and Cavit were placed in the access opening. The patient returned after 3 months, and the primary root canal was obturated using an injection-moulded thermoplasticized gutta-percha delivery system (Obtura II, Obtura Corp., Fenton, MO, USA) and zinc oxide-eugenol sealer. A postoperative radiograph was taken (Fig. 6). The patient was recalled periodically and healing was uneventful. The recall radiograph at 2 years showed osseous repair; the patient remained asymptomatic (Fig. 7).

Discussion

Clinicians should be aware of the incidence and methods for treating dens invaginatus . Failure to locate, debride and obturate complex root canal spaces will lead to failure in some cases. According to the classification of Oehlers (1957) the present case was a type 2. In this type of dens invaginatus , the invagination remains confined within the root as a blind sac, which may communicate with the pulp. However, in this case the invagination did not appear to communicate with the pulp and clinical exploration during root canal treatment corroborated this assumption. Therefore, the aetiology of the periapical pathosis in this case was due to the infected primary root canal. However, it is not known how long the primary root canal had been infected prior to the patient developing symptoms. Mechanical debridement of the primary root canal was difficult, but the combination of chemomechanical instrumentation and the use of calcium hydroxide were sufficient without resorting to surgery. As calcium hydroxide has been reported to successfully eliminate bacteria (Byström et al . 1985) and stimulate hard tissue repair (Heithersay 1975), it was decided to treat the primary root canal with this medicament before obturating the root canal with gutta-percha. The use of a warm gutta-percha technique helped to obturate the root canal system, as it was possible to compact the softened material into the major irregularities within the root canal system (Budd et al . 1991, Gutmann 1993).