title: Hypodontia patterns and variations in craniofacial morphology in Japanese orthodontic patients.
abstract: OBJECTIVE
  The purpose of this study was to explore the association of hypodontia patterns and variations in craniofacial morphology in Japanese orthodontic patients.
  
  
  METHODS
  A total of 50 girls with hypodontia (the total group) were selected and categorized into anterior, posterior, and anterior-posterior groups according to the location of the congenitally missing teeth. By using the lateral cephalograms of each subject, 28 angular and 37 linear measurements were made. The cephalometric data were statistically analyzed and compared among the groups and with the Japanese cephalometric standards from 36 age-matched female subjects without hypodontia or malocclusion (the control group).
  
  
  RESULTS
  Every hypodontia group showed shorter anterior and overall cranial base lengths, shorter maxillary length, greater retroclination and elongation of mandibular incisors, and a larger interincisal angle than the control group. The total and anterior-posterior groups especially exhibited a significantly more prognathic mandible, larger retroclination of maxillary incisors, and a more counterclockwise-rotated occlusal plane. Furthermore, these skeletal and dental deviations were more remarkable in the anterior-posterior group than in either the anterior or the posterior group. Anterior hypodontia exerted as much influence on craniofacial morphology as posterior hypodontia.
  
  
  CONCLUSIONS
  When orthodontic treatment is performed on patients with hypodontia, not only the number but also the distribution of missing teeth should be taken into consideration, though there was no significant difference in craniofacial morphology between anterior hypodontia and posterior hypodontia.
authors.affiliation: Department of Orthodontics, The Nippon Dental University Niigata Hospital, Niigata, Japan. endoto@ngt.ndu.ac.jp
authors.forename: Toshiya
authors.initials: T
authors.lastname: Endo
authors.forename: Rieko
authors.initials: R
authors.lastname: Ozoe
authors.forename: Sugako
authors.initials: S
authors.lastname: Yoshino
authors.forename: Shohachi
authors.initials: S
authors.lastname: Shimooka
mesh_terms: D000293:Adolescent; D000848:Anodontia / Q000150:complications / Q000473:pathology*; D044466:Asian People; D016022:Case-Control Studies; D002508:Cephalometry; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D007564:Japan; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008445:Maxillofacial Development; D009811:Odontometry; D011378:Prognathism / Q000150:complications; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology