title: Concomitant hypodontia and hyperodontia: an analysis of nine patients.
abstract: BACKGROUND
  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.
  
  
  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.
authors.affiliation: Department of Orthodontics, Medical University of Warsaw, Warsaw, Poland. malgorzatazadurska@wp.pl
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Zadurska
authors.forename: Barbara
authors.initials: B
authors.lastname: Sieminska-Piekarczyk
authors.forename: Dorota
authors.initials: D
authors.lastname: Maciejak
authors.forename: Barbera
authors.initials: B
authors.lastname: Wyszomirska-Zdybel
authors.forename: Jüri
authors.initials: J
authors.lastname: Kurol
mesh_terms: D000293:Adolescent; D000328:Adult; D000848:Anodontia / Q000150:complications*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D012744:Sex Ratio; D014083:Tooth Germ / Q000002:abnormalities; D014096:Tooth, Supernumerary / Q000150:complications*; D055815:Young Adult