Focal odontodysgenesis of the maxillary second premolars in a child.

A few months before her sixth birthday, a Caucasian girl suffered progressively worse episodes of painful, nontender, erythematous swellings of the palate lingual to apparently healthy primary second molars. Neither of the developing maxillary second premolars was discerned clearly in radiographs, but, upon surgical exploration, incomplete crowns were found in both follicles. All the other premolars appeared to be developing normally. Histologic, histochemical, and chemical analyses showed that the enamel was hypocalcified, apparently as a result of hypomaturation; the dentin was essentially normal; and morphogenesis had ceased when the heights of contour of the crowns had not yet been reached. This pattern of developmental defects differs from those of well-characterized odontogenic disorders, such as regional odontodysplasia and amelogenesis imperfecta. We suggest that focal odontodysgenesis might be an appropriate term for it. The bilateral symmetry suggests a genetic component in the etiology.