title: Effect of early or late eruption of permanent teeth on caries susceptibility.
abstract: OBJECTIVE
  The aim of this study was to analyse the possible effect of early or late eruption of permanent teeth on the placement of first restorations on the different surfaces. The oral health records, of a total of 486 children born in 1970 and 1971 living in three rural communities in Finland, were analysed.
  
  
  METHODS
  Caries susceptibility was determined indirectly by a new method. The study groups were defined as falling outside one standard deviation either side of the mean value for the timing of the eruption of first permanent molar teeth.
  
  
  RESULTS
  No statistically significant differences in restoration increments between the early and late eruption cohorts were found at the end of the study period. For the occlusal surfaces of the first molar teeth, the restoration placement curves plateaued at about 60-70%, while for the second molar teeth, the plateaus occurred at 50-60% for both study cohorts. In girls with 'late eruption', the height of the post-eruptive step (i.e. the number of teeth filled on the year of their eruption) was higher (50-100%) compared to boys and girls with 'early eruption'. The difference was statistically significant. For example, for the occlusal surface of D. 36, the 95% confidence interval for the difference between proportions was 12-53%.
  
  
  CONCLUSIONS
  No consistent effect of early or late eruption of permanent teeth was found on caries susceptibility measured post-eruptively by the placement rate of first restorations in a follow-up study of more than 10 years among Finnish children born in 1970-1971.
authors.affiliation: Department of Preventive Dentistry and Cariology, University of Oulu, Finland. Jorma.Virtanen@oulu.fl
authors.forename: J I
authors.initials: JI
authors.lastname: Virtanen
authors.forename: R S
authors.initials: RS
authors.lastname: Bloigu
authors.forename: M A
authors.initials: MA
authors.lastname: Larmas
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003733:Dental Caries Susceptibility; D003793:Dental Restoration, Permanent / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013997:Time Factors; D014078:Tooth Eruption