Dignosis and treatment of dens invaginatus with open apex in adult patient, by using cone-beam computed tomography and operative microscope

Aim: To present a clinical case of dens invaginatus, where the invagination gave rise to a structure radiologically similar to a tooth inside of a maxillary lateral incisor, that became necrotic before the complete formation of the apex.Methods: A 35-year old male patient referred a history of recurring abscesses with a vestibular fistula corresponding to the left maxillary lateral incisor. The intraoral periapical radiograph showed the presence of a periapical radiolucency of the 2.2 which had an open apex, and dentine tissue similar to a tooth within the pulp chamber. Cone Beam Computed Tomography (CBCT) confirmed the diagnosis of “dens invaginatus class II Ohler”. The concerned tooth did not respond to both electric and heat test. Provisional diagnosys was concluded as non-vital tooth with periapical lesion in relation to 2.2. After proper isolation with rubber dam an appropriate access cavity was prepared to allow the debridement of the necrotic pulp. A barbed broach was used for debridement. The glide path was performed with a manual K-file n. 10, which crossing the invaginated canal reached the immature apex at a working length of 22 mm measured by Root ZX apex locator. Thanks to the operating microscope it was possible to find access to the “real” endodontic space and to clean it circumferentially to the invaginated hard tissues. Gentle circumferential filing had been performed with minimal dentin removal using #80 H file. The canal was then irrigated with 5.25% NaOCl. Paper point had been introduced inside canal to dry it. Trying to follow and respect the C-shaped, already highlighted by CBCT. At first the whole endodontic space, both the real and the invaginated one, was filled with calcium hydroxide for 3 months. After 3 months the calcium hydroxide was removed by irrigation with 5.25% NaOCl, and the endodontic space was dried . The intraoral radiograph and CBCT showed that the internal hard structure was almost completely detached from the “real” canal walls; so, it was mobilized and removed with ultrasonic tip (StartX #3) through the access cavity, and the wide endodontic space was filled with MTA, condensed for approximately 3 mm by using a Schilder’s plugger and an ultrasonic tip for 10 seconds; it was covered with a moist cotton pellet, and the access was sealed with Cavit. One week later, a dual composite sealer (Relyx Unicem 2) was placed over the MTA cement, and the tooth was restored with an universal nano-hybrid composite (Tetric Evoceram). Results: After the first sessions of root canal shaping and medication with calcium hydroxide, the clinical symptoms and the fistula, which to date (two years) have not presented, disappeared. The radiographs, 12 months after the end of endodontic treatment, showed that the periapical lesion was gradually reduced both in size and intensity of gray.Conclusion: The cases of dens invaginatus may differ and consequently different is the treatment approach. In the case described, through the use of CBCT and the operating microscope, it was possible to locate and remove the hard tissue invaginated and then to proceed as a classic endodontic treatment of a tooth with open apex. The patient was included in a follow-up program to check and verify the complete periapical bone healing of the affected tooth.