title: Incidence and distribution of deciduous molar ankylosis, a longitudinal study.
abstract: OBJECTIVE
  To study incidence and distribution of deciduous molar ankylosis.
  
  
  METHODS
  study design: longitudinal retrospective study. A total of 512 consecutive subjects (aged 5 to 15 years) were examined at the Orthodontics and Paediatric Dentistry Department of the Genoa University School of Dentistry; for each subject an ortopantomography x-ray was taken.
  
  
  RESULTS
  Thirty-four children were affected by deciduous molars ankylosis (6.6%). A statistically significant difference was revealed between the distributions: the lower deciduous molars were ankylosed more frequently than the upper ones (P < 0.001); the second deciduous molars were ankylosed more frequently than the first molars (P < 0.001). No statistical significance was found between sex and number of infraoccluded teeth (P = 0.74).
  
  
  CONCLUSIONS
  This study found an incidence of deciduous molar ankylosis of about 6.6%; the lower deciduous molars and second deciduous molars were ankylosed more frequently (P < 0.001).
authors.affiliation: Department of Orthodontics, University of Genoa, Italy. armando.silvestrini@tin.it
authors.forename: A
authors.initials: A
authors.lastname: Silvestrini Biavati
authors.forename: A
authors.initials: A
authors.lastname: Signori
authors.forename: A
authors.initials: A
authors.lastname: Castaldo
authors.forename: G
authors.initials: G
authors.lastname: Matarese
authors.forename: M
authors.initials: M
authors.lastname: Migliorati
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008963:Molar / Q000473:pathology*; D011862:Radiography, Panoramic / Q000706:statistics & numerical data; D012189:Retrospective Studies; D020254:Tooth Ankylosis / Q000453:epidemiology*; D014094:Tooth, Deciduous / Q000473:pathology*