title: Tooth agenesis in a Portuguese population.
abstract: OBJECTIVE
  The aim of this retrospective study was to evaluate the prevalence and pattern of hypodontia in the permanent dentition, including and excluding third molars, in a Portuguese sample.
  
  
  METHODS
  The study group comprised 2888 patients, observed between 2005 and 2009 at the Dentistry Clinic of the Instituto Superior de Ciências de Saúde-Norte (ISCSN, Portugal). The patients were examined for evidence of hypodontia and presence or absence of deciduous teeth in those presenting agenesis. The age range varied from 7 to 21 years. In order to study the absence of the third molar, subjects under 14 years were excluded. Statistical analysis was performed using SPSS(®).
  
  
  RESULTS
  Excluding third molars, the prevalence of tooth agenesis was 6.1% for the Portuguese population. Tooth agenesis was found more frequently in females than in males, although this difference was not statistically significant (P>.05). The most commonly missing tooth was the mandibular second premolar, followed by maxillary lateral incisor, and maxillary second premolar. There was a significantly higher prevalence of missing third molars in the agenesis group than in the non-agenesis group. There was a correlation between second premolar and upper lateral agenesis with presence of their corresponding deciduous teeth.
  
  
  CONCLUSIONS
  The prevalence of tooth agenesis was found to be 6.1% for this Portuguese population and there was a correlation between agenesis and presence of deciduous teeth and between agenesis and missing third molars.
authors.affiliation: Department of Orthodontics, University of Valencia, Valencia, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: González-Allo
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Campoy
authors.forename: Joaquim
authors.initials: J
authors.lastname: Moreira
authors.forename: Josep
authors.initials: J
authors.lastname: Ustrell
authors.forename: Teresa
authors.initials: T
authors.lastname: Pinho
mesh_terms: D000293:Adolescent; D000848:Anodontia / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult