The relationship between hypodontia in the second premolar region and heredity of cleft, lip and palate in children with isolated cleft palate.

The aim of the investigation was to study the relationship between hypodontia in the second premolar region and heredity of cleft lip and palate (CLP) in children with isolated cleft palate (CP). The following null-hypothesis was tested: The heredity for CLP will not give rise to higher prevalence of hypodontia in the second premolar region of the maxilla and the mandible in CP-patients. The material consisted of 188 children born with non-syndromic CP (77 boys and 111 girls). Surgical files initiated at birth and panoramic radiographs at ten years of age have been studied concerning heredity for CLP and hypodontia of second premolars. For all CP-children, irrespective of hereditary background the prevalence of second premolar hypodontia did not differ significantly. However, there was a tendency to higher prevalence of hypodontia of the lower second premolars. The null-hypothesis: The heredity for CLP will not give rise to higher prevalence of hypodontia in the second premolar region of the maxilla and the mandible in CP-patients was not rejected.