Regional odontodysplasia represents a developmental disorder in which one or several teeth in a contiguous group fail to properly form. The condition occurs sporadically without a distinct familial pattern and most commonly affects the anterior maxillary quadrants. The involved teeth often fail to erupt, or if they do erupt, they are misshapen with irregular crowns and defective mineralization. Unerupted teeth are characterized by soft tissue swelling and painful symptoms.
Radiographic features typically consist of one tooth, or segment of teeth, demonstrating incomplete formation and reduced radiopacity. Because of their radiolucency, they are sometimes known as ghost teeth. In Figure 43, the posterior mandibular segment demonstrates an unerupted and incompletely mineralized second premolar and second molar. The first molar is absent and swelling of the overlying soft tissue is noted.