title: A radiographic study of tooth development in hypodontia.
abstract: OBJECTIVE
  To investigate the radiographic development of permanent teeth in a group of children (66 females and 69 males, aged 3.08-15.02 years) with agenesis of one or more permanent teeth compared to a matched group.
  
  
  METHODS
  Tooth formation of all developing permanent teeth was assessed using Haavikko's method (1970) from dental panoramic tomographs. The difference between dental and chronological age was tested using a paired t-test. The correlation between the difference of dental and chronological age and severity of hypodontia was investigated using Spearman correlation test. In addition, radiographs of all children with only one single missing tooth in one quadrant and no more than two agenesis in total (N=59), were analyzed using the non-parametric Wilcoxon sign test, in order to investigate if the development of the teeth adjacent to the site of the agenesis was effected.
  
  
  RESULTS
  Tooth formation in children with hypodontia was significantly delayed compared to the matched group (p<0.001). The mean difference was 1.51 years (S.D. 1.37 years). The severity of the hypodontia effected the magnitude of the delay (p<0.01). The teeth adjacent to the site of the agenesis were significantly delayed compared to the corresponding teeth in the matched group (p<0.01).
  
  
  CONCLUSIONS
  These results confirm that the development of permanent teeth in children with hypodontia is different when compared with a matched group.
authors.affiliation: Dental Institute, Barts and The London School of Medicine and Dentistry, Turner Street, Whitechapel, London E1 2AD, UK.
authors.forename: S
authors.initials: S
authors.lastname: Uslenghi
authors.forename: H M
authors.initials: HM
authors.lastname: Liversidge
authors.forename: F S L
authors.initials: FS
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000366:Age Determination by Teeth; D017677:Age Distribution; D000848:Anodontia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008297:Male; D009805:Odontogenesis; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D017678:Sex Distribution; D014070:Tooth / Q000000981:diagnostic imaging / Q000254:growth & development*