title: Age estimation using the radiographic visibility of the periodontal ligament in lower third molars in a Portuguese population.
abstract: OBJECTIVE
  The mineralization of third molars has been used repeatedly as a method of forensic age estimation. However, this procedure is of little use beyond age 18, especially to determinate if an individual is older than 21 years of age; thus, the development of new approaches is essential. The visibility of the periodontal ligament has been suggested for this purpose. The aim of this work was to determine the usefulness of this methodology in a Portuguese population.
  
  
  METHODS
  Periodontal ligament visibility was assessed in the lower third molars, using a sample of 487 orthopantomograms, 228 of which belonging to females and 259 to males, from a Portuguese population aged 17 to 31 years. A classification of four stages based on the visual phenomenon of disappearance of the periodontal ligament of fully mineralized third molars was used. For each stage, median, variance, minimal and maximal age were assessed.
  
  
  RESULTS
  The relationship between age and stage of periodontal ligament had a statistical significance for both sexes. In this population, stage 3 can be used to state that a male person is over 21 years-old; for females, another marker should be used.
  
  
  CONCLUSIONS
  This technique can be useful for determining age over 21, particularly in males. Differences between studies are evident, suggesting that specific population standards should be used when applying this technique. Key words:Forensic sciences, forensic odontology, age estimation, third molar, periodontal ligament.
authors: Faculdade de Medicina Dentária da Universidade do Porto. Porto, Portugal.
authors: Catarina-Dourado
authors: CD
authors: Sequeira
authors: Faculdade de Medicina Dentária da Universidade do Porto. Porto, Portugal.
authors: Alexandra
authors: A
authors: Teixeira
authors: Faculdade de Medicina Dentária da Universidade do Porto. Porto, Portugal ; CENCIFOR - Center of Forensic Sciences, Portugal. Associação Centro de Ciências Forenses. Coimbra, Portugal.
authors: Inês-Morais
authors: IM
authors: Caldas
authors: Faculdade de Medicina Dentária da Universidade do Porto. Porto, Portugal ; CENCIFOR - Center of Forensic Sciences, Portugal. Associação Centro de Ciências Forenses. Coimbra, Portugal.
authors: Américo
authors: A
authors: Afonso
authors: Faculdade de Medicina Dentária da Universidade do Porto. Porto, Portugal.
authors: Daniel
authors: D
authors: Pérez-Mongiovi