title: Radiographic study of delayed tooth development in patients with dental agenesis.
abstract: BACKGROUND
  The aims of this study were to compare the radiographic development of permanent teeth in a group of children affected by dental agenesis with an unaffected control group and to determine the effects of confounding factors including the severity of the dental agenesis, age, sex, ethnicity, and the number of stages used to estimate dental age.
  
  
  METHODS
  A single-center retrospective cross-sectional study of dental panoramic tomographs was undertaken between July 2007 and April 2008 in a postgraduate teaching school. A total of 139 patients (aged 9-18 years) were recruited from the orthodontic clinic on the basis of predetermined inclusion and exclusion criteria to either a dental agenesis group or a control group. Dental panoramic tomograms were assessed, and the stages of development of the permanent teeth in the left maxillary and left mandibular regions were scored by using the 12 stages of Haavikko and the 8 stages of Demirjian and Goldstein. For each tooth scored, the mean dental age and standard error were determined by using the dental age assessment method, and an estimated dental age for each subject was derived by using the weighted average method.
  
  
  RESULTS
  A statistically significant delay in dental age was found in the patients with dental agenesis compared with the control group. The dental age assessment method of Haavikko showed a delay of 1.20 years (SD, 1.74), and the method of Demirjian and Goldstein showed a delay of 1.64 years (SD, 1.75). It was also observed that older patients with dental agenesis had greater delays in tooth formation (P <0.001). With the Haavikko method, for every year of chronologic age, the delay in dental age increased by 0.53 year; with the Demirjian and Goldstein method, the delay increased by 0.48 year. A significant association was seen between the severity of dental agenesis and the delay in dental age (P <0.01). With both methods, for each additional developmentally absent tooth, the dental age was delayed by 0.13 year (lower confidence interval, -0.22; upper confidence interval, 0.35). There was no evidence that sex or ethnicity has an effect on the delay in dental age in patients with dental agenesis.
  
  
  CONCLUSIONS
  The development of permanent teeth in children with dental agenesis is delayed when compared with a matched control group. The severity of dental agenesis affected the magnitude of the delay (P <0.01). This delay has implications in orthodontic treatment planning and in the estimation of age for legal, immigration, archaeological, and forensic purposes.
authors.affiliation: Honorary specialist registrar in orthodontics, University College London Eastman Dental Institute for Oral Health Care Sciences, London, United Kingdom.
authors.forename: Erika V
authors.initials: EV
authors.lastname: Ruiz-Mealin
authors.affiliation: Clinical lecturer in paediatric dentistry, University College London Eastman Dental Institute for Oral Health Care Sciences, London, United Kingdom.
authors.forename: Susan
authors.initials: S
authors.lastname: Parekh
authors.affiliation: Consultant and honorary senior lecturer in orthodontics, University College London Eastman Dental Institute for Oral Health Care Sciences, London, United Kingdom.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Jones
authors.affiliation: Director, Postgraduate Education and Research, Peninsula Dental School, Plymouth, United Kingdom; professor, Oral Health Services Research, Peninsula Dental School, Plymouth, United Kingdom.
authors.forename: David R
authors.initials: DR
authors.lastname: Moles
authors.affiliation: Consultant and honorary senior lecturer in orthodontics, University College London Eastman Dental Institute for Oral Health Care Sciences, London, United Kingdom. Electronic address: daljit.gill@nhs.net.
authors.forename: Daljit S
authors.initials: DS
authors.lastname: Gill
mesh_terms: D000293:Adolescent; D000366:Age Determination by Teeth / Q000379:methods; D000367:Age Factors; D000848:Anodontia / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002648:Child; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging; D008437:Maxilla / Q000000981:diagnostic imaging; D009805:Odontogenesis / Q000502:physiology*; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D012737:Sex Factors; D014056:Tomography, X-Ray; D014083:Tooth Germ / Q000000981:diagnostic imaging / Q000254:growth & development