Two cases of regional odontodysplasia in girls are reported; one affected the lower incisors, and the other the left maxilla. The first case was radiographically followed over a 6-year period, during which time the ghost teeth exhibited significant dentin formation, along with a resultant decrease in pulp size and relative normalization of the radicular anatomy. The second case involved the deciduous molars and the first permanent molar. In addition to tooth alterations, both cases exhibited many odontogenic epithelial islands and extensive areas of calcification in the mucosa. Diagnosis, causes, and treatment are discussed in the light of recent data.