title: Dentoalveolar changes after unilateral extractions of mandibular first molars and their influence on third molar development and position.
abstract: OBJECTIVE
  To investigate the spontaneous tooth position changes after unilateral extraction of mandibular first molars and the influence on third molar position.
  
  
  METHODS
  Panoramic radiographs of 111 individuals (mean age 19 years 8 months) in whom one mandibular first molar was extracted at least 5 years prior. Comparison of all measurements of the control and the affected side was performed by paired Student t test.
  
  
  RESULTS
  The mandibular second molars tipped mesially, whereas the premolars, canines, and incisors moved distally toward the extraction space. Vertical alveolar resorption was significant, particularly in older patients. Mesial inclination of the third molar occurred in only subjects in whom this tooth was completely developed. No significant vertical change of the third molars was observed.
  
  
  CONCLUSIONS
  Unilateral extraction of mandibular first molars causes a significant displacement of all teeth of the affected side toward the extraction site and a progressive vertical bone resorption of this area. The closer the teeth are to the extraction site, the more they are affected. No significant changes were observed on third molar vertical position.
authors.affiliation: Department of Orthodontics, Federal University of Pará, Faculty of Dentistry, Belém, Brazil. davidnor@amazon.com.br
authors.forename: Antonio David Corrêa
authors.initials: AD
authors.lastname: Normando
authors.forename: Francisco Ajalmar
authors.initials: FA
authors.lastname: Maia
authors.forename: Weber José da Silva
authors.initials: WJ
authors.lastname: Ursi
authors.forename: José Leonardo
authors.initials: JL
authors.lastname: Simone
mesh_terms: D000293:Adolescent; D000328:Adult; D016301:Alveolar Bone Loss / Q000473:pathology; D001641:Bicuspid / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D002648:Child; D003481:Cuspid / Q000473:pathology; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008334:Mandible / Q000473:pathology*; D008963:Molar / Q000601:surgery*; D008964:Molar, Third / Q000473:pathology*; D009805:Odontogenesis / Q000502:physiology; D011862:Radiography, Panoramic; D014078:Tooth Eruption / Q000502:physiology; D014081:Tooth Extraction / Q000379:methods*; D014085:Tooth Migration / Q000473:pathology; D055815:Young Adult