Introduction: Congenital absence of tooth germs and presence of supernumerary teeth (CHH) are anomalies which are classified as embryologically determined disorders. Both disorders can occur together (CHH), but relatively rarely.
Objective: The aim of the present study was to present and analyze nine cases collected during the past 24 years, where congenitally missing teeth occurred with supernumerary teeth in the same patient.
Materials and methods: Dental records, radiographs and casts of nine patients, six boys and three girls (aged 9-29 years, mean age: 19 years) were examined. All the family members of the patients were also investigated regarding the presence of tooth disorders.
Results: The boys showed hypo-hyperodontia twice as often as the girls (6:3). Congenital absence of tooth germs was more common than the presence of supernumerary teeth (25:11). CAP were not present in the other family members.
Conclusions: The full diagnosis of hypo-hyperodontia is only possible on the basis of radiographic examination, because some teeth may remain unerupted or missing. The results of this study showed that concomitant hypo-hyperodontia is rare and sex-related, with predominance of hypodontia. The genetic influence seems unclear.