title: Places in the dental arch that show a greater variability in tooth number, shape and position--a prevalence study.
abstract: OBJECTIVE
  The aim of this study was to assess the frequency of variations in tooth number, shape and position in the dental arch to determine if there are parts of the dental arch that show a higher prevalence of tooth variability.
  
  
  METHODS
  198 randomly selected Caucasian subjects (93 females, 105 males) aged between 10.0 and 24.5 years (mean age 14.15, SD 2.34 years) were included. A total of 5544 teeth were examined and dental anomalies of tooth number, shape and position (oral teeth positions and teeth rotations greater than 45°) were recorded.
  
  
  RESULTS
  18.68 per cent of the subjects had one or more unerupted teeth. Aplasia as the cause of uneruption was found in 12.12 per cent of the subjects, statistically significantly more frequently in females than males (Fisher test, p < 0.05). Tooth shape anomalies were found in 6.57 per cent of the sample, more frequently in males than females (Fisher test, p < 0.05). Oral position of one or more teeth was found in 47.98 per cent of the sample, whilst rotations greater than 45° were found in 15.66 per cent, with no statistically significant differences between females and males. One or more of the observed dental anomalies were found in several tooth types, however all the observed dental anomalies were found only in second premolars and in upper lateral incisor.
  
  
  CONCLUSIONS
  According to the results of this study, it seems that some places in the dental arch show a greater variability in terms of tooth number, shape and position. This could be a result of genetic and environmental influences during odontogenesis or a result of evolutionary trends.
authors.affiliation: Department of Dental and Jaw Orthopaedics, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia. jasminaprimozic@gmail.com
authors.forename: Jasmina
authors.initials: J
authors.lastname: Primožič
authors.forename: Franc
authors.initials: F
authors.lastname: Farčnik
authors.forename: Maja
authors.initials: M
authors.lastname: Ovsenik
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000002:abnormalities; D016009:Chi-Square Distribution; D002648:Child; D003724:Dental Arch / Q000254:growth & development*; D005260:Female; D006801:Humans; D007180:Incisor / Q000002:abnormalities; D008297:Male; D008445:Maxillofacial Development; D015995:Prevalence; D017524:Slovenia / Q000453:epidemiology; D014071:Tooth Abnormalities / Q000453:epidemiology*; D014097:Tooth, Unerupted / Q000453:epidemiology*; D055815:Young Adult