title: Display of the incisors as functions of age and gender.
abstract: BACKGROUND
  Older subjects usually show less of their upper incisors and more of their lower incisors than younger subjects.
  
  
  OBJECTIVE
  To determine how much of the upper and lower central incisor crowns are visible in Brazilian subjects with their lips at rest.
  
  
  METHODS
  The subjects were 240 white Brazilian subjects divided into four age groups: Group 1, 12 to 15 years of age; Group 2, 20 to 30 years of age; Group 3, 31 to 50 years of age and Group 4, 51 years of age and older. Each group contained 30 males and 30 females. The vertical display of the incisors was measured in millimetres from the midpoints of the incisal edges of the upper and lower central incisors to the borders of the upper and lower lips.
  
  
  RESULTS
  In females, the mean upper central incisor display reduced from 4.45 mm in Group 1 to 1.32 mm in Group 4, and in males it reduced from 3.35 mm in Group 1 to 0.57 mm in Group 4. Less of the lower central incisor crowns were displayed in Group 1 females (Mean: 0.47 mm) than in Group 4 females (Mean: 2.22 mm), and in Group 1 males (Mean: 0.61 mm) than in Group 4 males (Mean: 3.05 mm). Brazilian women showed significantly more of their upper incisor crowns than Brazilian men in Groups 1, 2 and 4, whereas Brazilian men showed significantly more of their lower central incisors than Brazilian women in Group 4.
  
  
  CONCLUSIONS
  With the lips at rest, older Brazilians display less of their upper central incisors and more of their lower central incisors than young Brazilians. Women show more of their upper incisors than men, while men display more of their lower central incisors than women.
authors.affiliation: Department of Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. afjmotta@gmail.com
authors.forename: Andrea Fonseca Jardim
authors.initials: AF
authors.lastname: da Motta
authors.forename: Margareth Maria Gomes
authors.initials: MM
authors.lastname: de Souza
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Bolognese
authors.forename: Clarice Júlia
authors.initials: CJ
authors.lastname: Guerra
authors.forename: José Nelson
authors.initials: JN
authors.lastname: Mucha
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001938:Brazil; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology*; D008046:Lip / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D009811:Odontometry; D012737:Sex Factors; D019228:Tooth Crown / Q000033:anatomy & histology*; D014716:Vertical Dimension; D055815:Young Adult