A modification of the Demirjian method for age estimation in children.

The Demirjian method for age estimation in children by means of dental development is widely used and forms a basis on which a universal dental maturity score can be calculated. This score is then translated into a chronological age with aid of tables specific for each population. Such tables are, however, available for only a few populations and usually not where age estimations are needed. In several studies on age estimation in children it has been found that the original studies by Demirjian and co-workers do not give enough information to allow the construction of corresponding tables for other populations. The main reason for this is that the regression lines in the original graphs were obtained by manual smoothing to combine the individual plots and the tables were thereafter compiled from these graphs. In an attempt to avoid manual, and more or less subjective, construction of the regression line, an attempt was made to fit the plots into a regression line by a series of predefined functions. The aim was to find a model with the best possible explanation factor of the correlation between dental maturity score and chronological age. A cubic function was found to give a good fit to the plots with an R2 of about 0.95. This modification of the original Demirjian method for age estimation of children is therefore recommended for the construction of population-specific tables. The use of a mathematical function also makes it possible to calculate confidence intervals to be used to describe the accuracy of an individual estimation.