title: Delayed development or congenital absence of a single first permanent molar in Japanese child patients.
abstract: OBJECTIVE
  Delayed eruption of the first permanent molar (M1) is a relatively rare finding. This report describes the occurrence of delayed development and eruption of a single M1 in Japanese child patients.
  
  
  METHODS
  Cases were identified by surveying 353 orthopantomograms taken of child patients attending a Dental Hospital. Dental age, crown morphology and the presence of third permanent molars (M3) were determined from radiographs and clinical examination.
  
  
  METHODS
  Osaka University Dental Hospital in Japan.
  
  
  RESULTS
  Nine cases were identified from radiographs. The occlusal morphology of the affected molars showed a reduction of the distolingual cusp. Dental ages correlated more closely to chronological ages when the affected teeth were assumed to be second permanent molars (M2) than they did when the teeth were assumed to be M1. M3 proximate to the affected molar was congenitally absent in the orthopantomograms of all affected subjects.
  
  
  CONCLUSIONS
  It is suggested that in the cases seen here the affected teeth were likely to have been second permanent molars that had migrated mesially in association with the congenital absence of M1, although congenital absence of M1 has been reported to be extremely rare.
authors.affiliation: Department of Pedodontics, Osaka University Faculty of Dentistry, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakano
authors.forename: T
authors.initials: T
authors.lastname: Matsuoka
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Matsumura
authors.forename: S
authors.initials: S
authors.lastname: Sobue
authors.forename: T
authors.initials: T
authors.lastname: Ooshima
mesh_terms: D000293:Adolescent; D000366:Age Determination by Teeth / Q000379:methods; D000848:Anodontia / Q000150:complications / Q000000981:diagnostic imaging / Q000209:etiology; D002648:Child; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging; D008445:Maxillofacial Development; D008644:Mesial Movement of Teeth / Q000000981:diagnostic imaging / Q000209:etiology; D008963:Molar / Q000000981:diagnostic imaging / Q000254:growth & development* / Q000503:physiopathology; D009811:Odontometry; D011862:Radiography, Panoramic; D014078:Tooth Eruption; D014097:Tooth, Unerupted / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology