Dr. Garth Hatch discusses how CBCT helped diagnose a case of dens invaginatus
A 13-year-old Caucasian female was referred to our clinic for an endodontic evaluation of tooth No. 9 following dental trauma.
The patient had a history of trauma to the maxillary anterior region approximately 2 weeks prior from falling face first onto a cement floor. Spontaneous throbbing and tenderness to cold and hot were noted for the last 3 days in the maxillary anterior region. Lingering tenderness to cold, percussion, and palpation were noted with tooth No. 9 during the intraoral examination. Teeth Nos. 6, 7, 8, 10, and 11 responded within normal limits to cold, percussion, and palpation. The diagnosis for tooth No. 9 was symptomatic irreversible pulpitis with symptomatic apical periodontitis related to recent dental trauma of the maxillary anterior region.
The initial periapical radiograph taken revealed an unusual mesial root anatomy of tooth No. 10 with two separate pulp canals noted. A large periapical radiolucency (PARL) was also noted on the coronal two-thirds of the mesial root of tooth No. 10 apical to the accessory root. A 3D cone beam image of the maxillary anterior region was also taken with a Carestream CS 8100 3D CBCT. The CBCT image revealed a mesial accessory root with a pulp chamber separated from the main pulp chamber of tooth No. 10. A root invagination also presented, separating the two canals consistent with dens invaginatus.
Classification of dens invaginatus
Several dental classifications exist to describe dens invaginatus, including ones developed by Hallett in 1953. The most widely used classification system for dens invaginatus was developed by Oehlers in 1957 and revisited with Alani and others. Oehlers categorizes invaginations into three classes as determined by how far the extension is radiographically from the crown into the root.
The invagination is minimal and enamel lined; it is confined within the crown of the tooth and does not extend beyond the level of the external amelo-cemental junction.
The invagination is enamel lined and extends into the pulp chamber but remains within the root canal with no communication with the periodontal ligament.
The invagination extends through the root and communicates laterally with the perio-dontal ligament space through a pseudo-foramen. There is usually no communication with the pulp, which lies compressed within the root.
The invagination extends through the root and communicates with the periodontal ligament at the apical foramen. There is usually no communication with the pulp.
Treatment options were discussed, and the patient and her mother consented to nonsurgical root canal therapy of tooth No. 9 and to monitor tooth No. 10. The patient and parent were advised on the questionable long-term prognosis of tooth No. 10 due to dens invaginatus (Oehlers’ Type IIIA) with a significant PARL. The patient will monitor tooth No. 10 and treat as needed, ideally once the patient has fully matured in case extraction is indicated.
- Hallett GE. The incidence, nature, and clinical significance of palatal invaginations in the maxillary incisor teeth. Proc R Soc Med. 1953;46(7):491-499.
- Oehlers FA. Dens invaginatus. I. Variation of the invagination process and associated anterior crown forms. Oral Surg Oral Med Oral Pathol. 1957;10:1204-1218.
- Alani A, Bishop K. Dens invaginatus. Part 1: classification, prevalence, and aetiology. Int Endod J. 2008;41(12):1123-1136.