Dens evaginatus is the result of an outpouching of the enamel organ. The
resultant enamel-covered tubercle usually occurs in or near the middle of
the occlusal surface of a premolar or occasionally a molar.
Lateral incisors are most commonly involved, whereas canines are rarely
affected.
The frequency of occurrence of dens evaginatus is highest in Asians and
Native Americans.
Clinical Features
Clinically, dens evaginatus appears as a tubercle of enamel on the
occlusal surface of the affected tooth.
A hard, polyplike protuberance predominantly exists in the central groove
or lingual ridge of a buccal cusp of posterior teeth and in the cingulum
fossa of anterior teeth.
Dens evaginatus may occur bilaterally and usually in the mandible.
The tubercle often has a dentin core, and a very slender pulp horn
frequently extends into the evagination.
After the tubercle is worn down by the opposing teeth, it appears as a
small circular facet with a small black pit in the center.
Wear, fracture, or indiscriminate surgical removal of this tubercle may
precipitate a pulpal infection because of the exposure of the pulp horn.
In rare cases a microscopic direct communication may occur between the
pulp and the oral cavity through this tubercle. In these instances the pulp
may become infected shortly after eruption.
Radiographic Features
The radiographic image shows an extension of a dentin tubercle on the
occlusal surface unless the tubercle is already worn down.
The dentin core is usually covered with opaque enamel.
A fine pulp horn may extend into the tubercle, but this may not be visible
radiographically.
If the tubercle has been worn to the point of pulpal exposure or has
fractured, pulpal necrosis may result.
This is indicated by an open apical foramen and periapical radiolucency.
Multiple root formation is often associated with dens evaginatus,
especially in mandibular premolars.
Management
If the tubercle causes any occlusal interference or shows evidence of
marked abrasion, it should probably be removed under aseptic conditions
and the pulp capped, if necessary.
Such a precaution may preclude pulpal exposure and infection as the
result of accidental fracture or advanced abrasion.