title: [A survey of number and morphology anomalies in permanent teeth of 6 453 youths between 17 to 21 years old].
abstract: OBJECTIVE
  To investigate the status of number and morphology anomalies in the permanent teeth.
  
  
  METHODS
  A survey of anomalies of number and morphology in the permanent teeth was carried out in 6 453 students who were 17 to 21 years old in 3 colleges during 2002 to 2004. Chi-square test was used to analyze the sex distribution, the involved tooth types and the associated anomalies.
  
  
  RESULTS
  The overall prevalence of dental number and morphology anomalies was 16.07%. The prevalence rates of peg-shape (conical) tooth, dens evaginatus and hypodontia were higher in females compared to males (P < 0.05). Dens evaginatus and peg-shape teeth often involved maxillary lateral incisors, Dens evaginatus often involved mandibular second premolars. Fused teeth and hypodontia often involved mandibular incisors. The prevalence of hypodontia coincident with peg-shaped teeth was higher than other associated anomalies (P < 0.01).
  
  
  CONCLUSIONS
  The result was similar to other investigations, but peg-shape teeth and dens evaginatus were more prevalent in females than in males.
authors.affiliation: Department of Prosthodontics, Peking University School of Stomatology, Beijing 100081, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
authors.forename: Hai-lan
authors.initials: HL
authors.lastname: Feng
mesh_terms: D000293:Adolescent; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012737:Sex Factors; D013334:Students; D014071:Tooth Abnormalities / Q000453:epidemiology*; D055815:Young Adult