Frequency of dental trait anomalies in cleft, sibling, and noncleft groups.

The incidence and types of dental trait anomalies found in individuals with cleft lip or cleft palate or both (cleft group), in siblings of the cleft group, and in a group of individuals without cleft lip or cleft palate (noncleft group) were compared. The cleft group had 1.02 anomalies per individual, the sibling group, 0.38; and the noncleft group, 0.17. The frequency of occurrence of thick-curved maxillary central incisors, incisal fissures, and missing teeth were significantly different among the three groups.