title: A prospective cohort study on emergence of permanent teeth and caries experience in Korean children.
abstract: OBJECTIVE
  The objectives of this study were to investigate permanent tooth emergence during a 9-year longitudinal study and to assess the effect of dental caries in primary teeth on the emergence of permanent teeth.
  
  
  METHODS
  Data on caries occurrence in primary teeth were obtained at the baseline by a trained dentist. Permanent tooth emergence data of 539 students from 16 elementary schools in Yeoncheon were examined annually from 1995 to 2003 using dental casts. The median age at emergence of the teeth was calculated using a linear logistic regression model. A multiple linear regression model was used to evaluate the effect of caries on the emergence of permanent teeth.
  
  
  RESULTS
  The age of permanent tooth emergence was different between boys and girls, but the difference was not statistically significant at the 5% level. Having 'decayed teeth' hastened the emergence of most second premolars and second molars, whereas the regression coefficients ranged from -1.23 to -0.82. The number of 'filled teeth' showed a correlation with maxillary second premolars and mandibular first premolar, and the regression coefficients ranged from -1.92 to -3.25.
  
  
  CONCLUSIONS
  Having dental caries in primary teeth can be a strong predictor of earlier emergence of permanent teeth.
authors.affiliation: Department of Statistics, College of Natural Sciences, Pusan National University, Pusan, Korea.
authors.forename: Choongrak
authors.initials: C
authors.lastname: Kim
authors.forename: Younghee
authors.initials: Y
authors.lastname: Hong
authors.forename: Dong-Hun
authors.initials: DH
authors.lastname: Han
authors.forename: Hae-Kyung
authors.initials: HK
authors.lastname: Hong
authors.forename: Young-Nam
authors.initials: YN
authors.lastname: Kim
authors.forename: Kwang-Hak
authors.initials: KH
authors.lastname: Bae
mesh_terms: D000367:Age Factors; D001641:Bicuspid / Q000473:pathology; D002648:Child; D015331:Cohort Studies; D003481:Cuspid / Q000473:pathology; D004245:DMF Index; D003731:Dental Caries / Q000473:pathology*; D003793:Dental Restoration, Permanent / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible; D008437:Maxilla; D008963:Molar / Q000473:pathology; D011446:Prospective Studies; D056910:Republic of Korea; D012737:Sex Factors; D014078:Tooth Eruption / Q000502:physiology*; D014094:Tooth, Deciduous / Q000473:pathology*