Dens invaginatus | |
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Other names | Dens in dente, tooth within a tooth |
Specialty | Dentistry |
Dens invaginatus (DI), also known as tooth within a tooth, is a rare dental malformation and a developmental anomaly where there is an infolding of enamel into dentin. The prevalence of this condition is 0.3 - 10%,[1] affecting males more frequently than females. The condition presents in two forms, coronal involving tooth crown and radicular involving tooth root, with the former being more common.[2]
DI is a malformation of teeth most likely resulting from an infolding of the dental papilla during tooth development or invagination of all layers of the enamel organ in dental papillae. Affected teeth show a deep infolding of enamel and dentin starting from the foramen coecum or even the tip of the cusps and which may extend deep into the root. Teeth most affected are maxillary lateral incisors (80%),[3] followed by maxillary canines (20%).[3] Bilateral occurrence is also seen (25%).[3]
DI is often asymptomatic with the affected crown showing minimal external deformity. Individuals with an affected tooth may complain of their tooth having an abnormal shape such as being wider mesio-distally or bucco-lingually. [4]
Teeth affected by this condition are at a higher risk for developing caries and periradicular pathology.[1] The thin layer of the infolding enamel could be chipped off easily, providing entrance for microorganisms into the root canal. This can cause abscess formation and displacement of dental structures (i.e. teeth).[5] Early diagnosis and prevention is very important for maintaining tooth vitality. Clinical features such as incisal notching or pronounced talon cusp on lateral incisors could hit at DI and should be investigated with radiographs. [4]
Cause of DI is unclear. However, there are several theories:
During clinical examination,[6] abnormally shaped tooth can be observed. Teeth with this condition can have a conical shape or deep pit on the lingual side or have an exaggerated talon cusp.
Although examination may reveal a fissure on the surface of anterior tooth, radiographic examination is the way.[7] On a periapical radiograph, the invagination lesion will appear as a radiolucent pocket. It is usually seen beneath the cingulum or incisal edge. Larger lesions can appear as fissures. A radio-opaque could be shown. Pulp may be involved and the root canal could have complex anatomy. Two periapical radiographs are often required to make sure that it is not a masked lesion.
Cone beam computed tomography[8][9] (CBCT) is useful in diagnosing DI. It provides clinicians a detailed 3D image and could aid treatment planning. Feasibility of root canal treatment or apical surgery or other procedures could be assessed.