title: Frequency and characteristics of tooth agenesis among an orthodontic patient population.
abstract: OBJECTIVE
  The objectives of this study were to investigate the prevalence and characteristics of tooth agenesis and the associated skeletal morphology and arch widths in a group of Turkish patients seeking orthodontic treatment.
  
  
  METHODS
  We designed a retrospective study composed of pre- and post-treatment panoramic radiographs and lateral cephalometric films of 3,341 patients (2,040 females and 1,301 males). Tooth agenesis was evaluated for hypodontia and oligodontia -excluding the third molars- from the orthopantomograms. The significance test for the differences in the skeletal morphology between hypodontia and non-hypodontia patients was performed using the Pearson chi-square and Student t-test.
  
  
  RESULTS
  The prevalence of tooth agenesis was 4.6 percent for the Turkish orthodontic patient population. Tooth agenesis was found more frequently in females than in males, although this difference was not statistically significant (p>0.05). The most commonly missing teeth were the maxillary lateral incisors, followed by the mandibular second premolars and mandibular central incisors. Intercanine and intermolar widths in the maxillary and mandibular arches were significantly reduced in the hypodontia group compared with the control group (p<0.01). Tooth agenesis was statistically and significantly less in patients with skeletal Class II (p<0.01). There was no statistically significant difference in hypodontia patients in the vertical relationship of the jaws (p>0.05).
  
  
  CONCLUSIONS
  The prevalence of tooth agenesis was found to be 4.6 percent for the Turkish orthodontic patient population (hypodontia 4.3% and oligodontia 0.3%), and was found more frequently in females. Intercanine and intermolar widths were significantly reduced in the hypodontia group for both jaws compared with the control group.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey.
authors.forename: Mevlut
authors.initials: M
authors.lastname: Celikoglu
authors.forename: Fatih
authors.initials: F
authors.lastname: Kazanci
authors.forename: Ozkan
authors.initials: O
authors.lastname: Miloglu
authors.forename: Ozkan
authors.initials: O
authors.lastname: Oztek
authors.forename: Hasan
authors.initials: H
authors.lastname: Kamak
authors.forename: Ismail
authors.initials: I
authors.lastname: Ceylan
mesh_terms: D000293:Adolescent; D000328:Adult; D000848:Anodontia / Q000175:diagnosis* / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009970:Orthodontics; D015995:Prevalence; D012189:Retrospective Studies; D014421:Turkey / Q000453:epidemiology; D055815:Young Adult