title: Effect of early restorations of permanent molars on filling increments of individual teeth.
abstract: OBJECTIVE
  The purpose of this work was to analyse longitudinally whether the placement of restorations on permanent molar teeth immediately after their eruption results in (a cohort with) higher filling increments in all individual teeth thereafter. The patient documents of 937 subjects born either in 1970-1971 or in 1980-1981 were analysed.
  
  
  METHODS
  The methods of survival analysis were employed. If any of the first permanent molar teeth had been restored in the course of tooth emergence, the person was assigned to the experimental group, and all the others were placed in the control group. Those in whom all the first permanent molar teeth had been restored at the time of emergence were compared with all the others.
  
  
  RESULTS
  Early restoration of any permanent molar indicated higher filling increments in all the other molar teeth. The differences between the groups with regard to the first and second molar teeth were statistically highly significant (e.g. D.17 for the girls: log-rank chi 2 = 32.8, p = 0.0001 and Wilcoxon chi 2 = 28.7, p = 0.0001). The differences were greater among the girls than among the boys. Early restoration of the first permanent molar teeth did not indicate high filling increments in the incisors, canines or the smooth surfaces of any tooth.
  
  
  CONCLUSIONS
  Fissure caries and smooth surface caries are different entities. The present method can be of help as an additional tool to help the clinician identify "risk" patients, in that an early restoration in any first molar is a powerful indicator of a risk of restorations in the other first molar teeth and also the second molar teeth.
authors.affiliation: Department of Preventive Dentistry and Cariology, University of Oulu, Finland.
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; D000328:Adult; D000367:Age Factors; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004245:DMF Index; D003731:Dental Caries / Q000453:epidemiology*; D003732:Dental Caries Activity Tests / Q000706:statistics & numerical data*; D003750:Dental Fissures / Q000453:epidemiology; D003793:Dental Restoration, Permanent / Q000706:statistics & numerical data*; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D008963:Molar; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013997:Time Factors; D014078:Tooth Eruption