an infolding lined by enamel within the crown of the tooth, sometimes extending into
the root. An invagination of enamel epithelium into the dental papilla during
development leads to the formation of the abnormality. The terms invaginated tooth
or dens invaginatus can be used; other terms commonly applied (but not necessarily
correctly) are dens in dente, gestant composite odontome, and dilated composite
odontome.
The maxillary lateral incisor is the most commonly affected tooth (815HFig. 13.17 (a) and
(b)). The maxillary central incisors are less commonly affected and, occasionally, the
canines are affected. In its mildest form an invaginated tooth is typically a maxillary
lateral incisor with a deep cingulum pit on the palatal aspect of the crown. In its more
extreme form the invagination is associated with a grossly abnormal crown form and
root form (816HFig. 13.18). In these gross examples the crown is tuberculate with the
invagination appearing on the cusp of the abnormal tooth. Radiographs show the
extent of the invagination chamber. Enamel, which may be extremely thin and may
even be absent, can be seen lining this chamber. The pulp may be displaced and
surround the invagination cavity, appearing radiographically as narrow slits around
the dentine forming the wall of the invagination. Sometimes the root is significantly
expanded.
Invagination of primary teeth is uncommon but in the permanent dentition has been
estimated to affect between 1% and 5% of different groups. Males are more
commonly affected than females, with a ratio of 2 : 1. Invaginations may also differ in
different racial groups, with people of Chinese ethnicity being reportedly more
commonly affected.
Invaginated teeth may cause problems because of the development of caries and
pulpal pathology. This can occur soon after tooth eruption, with the child presenting
an acute abscess or facial cellulitis. In such cases the radiograph will invariably
demonstrate incomplete root formation as well as periapical rarefaction (817HFig. 13.17 (a)
and (b)). The presence of one invaginated tooth should lead to consideration of the
contralateral tooth and/or adjacent teeth being affected. Invaginations are often
bilateral, though not necessarily symmetrical. Some patients with invaginated teeth
may also have supernumerary teeth and therefore full radiographic examination is
warranted.
Treatment
If invaginations are identified at an early stage after eruption of the tooth then etch-
retained resin sealants can be placed to prevent bacteria entering the invagination and
subsequent development of caries. Acute infective episodes, particularly when
associated with cellulitis, should be treated with appropriate antibiotic therapy as well
as incision and drainage of any pointing abscess. The tooth should be opened, or
extracted if the long-term prognosis is poor. This tends to be the case with the more
gross examples where the crown and root form are abnormal. In less extreme forms
endodontic treatment, firstly involving apexification, can be considered.