IADR Abstract Archives
Development of Tooth Eruption Models to guide Fissure Sealing Programmes, Supported by HRB Project Grant RP/2005/209
Objectives: To develop a model for the eruption of first permanent molars to guide fissure sealing programmes. Background: Oral health services are provided free of charge to primary school children in RoI by salaried dentists employed by the HSE Dental Service. The routine services provided include fissure sealant placement. Although there are variations across administrative areas, most children are screened in second class (aged approx 8 years) when any first permanent molars that are erupted and free from caries are sealed. The targeting of children for fissure sealing by school class is inefficient because of individual variations in eruption patterns and caries risk. Thus, a more individualised approach is required to identify children and teeth at the optimum time for fissure sealant placement. Methods: We developed a reasonable probit function to model the proportion of a first permanent molar that has erupted in an individual. For a randomly chosen individual the erupted proportion at time 
will be 
where 
. The expected proportion of erupted teeth in the population at time can be shown to satisfy 
. Therefore, the observed number of erupted teeth for individuals aged in a sample of size 
will be Binomial 
and a probit analysis of the North South Survey of Children’s Oral Health allows the values of 
and 
to be determined. Results: Simulated analyses using the simple model for the population, 
, with the addition of an error term, provided results consistent with literature for a longitudinal study of the eruption of first permanent molars. Conclusions: Our probit model has been found consistent with published results on tooth eruption from longitudinal studies. This simple model can now be expanded and advanced using covariates that are linked to tooth eruption e.g. gender, upper/lower jaw, etc.
will be . The expected proportion of erupted teeth in the population at time can be shown to satisfy . Therefore, the observed number of erupted teeth for individuals aged in a sample of size