Dens in dente

Clinical History

A 7-year-old girl was referred to the stomatology department for dental cavities and an "abnormal" tooth. The unerupted tooth 22 showed enamel invagination and an orthopantomogram was performed. As there were doubts as to the extent of invagination, a dose adjusted CT scan was performed for therapeutic decision-making.

Imaging Findings

Imaging of dens invaginatus in a 7-year-old child is shown.

The axial views of teeth 12 and 22 show two concentric hyperdense rings, the outer tooth enamel and the inner invaginated enamel, compatible with the classical “target-like” conformation. The invaginated enamel tends to be hyperdense, when compared with the outer enamel of the tooth, which stands out in the axial view of tooth 12. The coronal and sagittal views show the same hyperdense enamel invaginated inside the pulp space extending deep inside the root to the incomplete apex.

Despite immature dentition, it seems that the inner enamel layer doesn’t have an apical opening, rendering highly likely the development of a Type II dens invaginatus.

Discussion

Dens in dente, or dens invaginatus, is a malformation of teeth resulting from a deepening or invagination of the enamel organ into the dental papilla [1, 2]. It is idiopathic, but an elevated family incidence has been established. Teeth most affected are maxillary lateral incisors [3], and bilateral occurrence is not uncommon (up to 43% patients) [1, 2]. In addition, patients with evidence of dens invaginatus may have other dental anomalies, malformations and syndromes [2]. Tooth crown and root may have a normal anatomy, but several morphologic variations/anomalies have been described [1].
When clinically suspected, diagnosis and initial imaging (intraoral radiograph and/or OPT) are usually performed at the dental clinic. More complex cases may render (CB) CT necessary. It may also be an incidental finding on radiographic imaging of the head and neck region. The radiological appearance of invagination is a radiolucent pocket surrounded by a radio-opaque enamel border, varying in distance from the incisal edge and proximity to the dental pulp [2]. There may be an enamel-lined fissure opening into the periodontal ligament, described as a ‘pseudo-canal’ [2].
Oëhler’s classification (1957) is most commonly used, determined by how far the invagination extends from the crown into the root [1, 4, 6]-
Type I (79%): An enamel-lined minor form occurring within the crown, not extending beyond the amelocemental junction.
Type II (15%): an enamel-lined form which invades the root but remains confined as a blind sac. It may or may not communicate with the dental pulp.
Type III (5%): a form which penetrates through the root perforating at the apical area showing a ‘second foramen’ in the apical or in the periodontal area. There is no immediate communication with the pulp. The invagination may be completely lined by enamel or cementum.
The presence of an invagination is considered to increase the risk of caries, pulp pathosis and periodontal inflammation, making prophylactic treatment essential for prognosis. Treatment depends on the severity of the pulp disease, but often requires root canal treatment, endodontic microsurgery or even extraction [2, 7]. The aberrant anatomy of these teeth may influence the complexity of dental treatment and (CB)CT may provide valuable information in treatment planning, especially in case of endodontic microsurgical planning [8, 9].
Take home messages:
Dens in dente may be an incidental finding on imaging (radiography/CT) but should be noted, as these teeth are at increased risk of developing tooth decay and pulpal necrosis.

Differential Diagnosis List

Final Diagnosis

Bilateral symmetrical dens in dente

URL:	https://www.eurorad.org/case/13283
DOI:	10.1594/EURORAD/CASE.13283
ISSN:	1563-4086