Precision and accuracy of commonly used dental age estimation charts for the New Zealand population

Abstract

Little research has been undertaken for the New Zealand population in the field of dental age estimation. This research to date indicates there are differences in dental developmental rates between the New Zealand population and other global population groups, and within the New Zealand population itself.Dental age estimation methods range from dental development charts to complex biometric analysis. Dental development charts are not the most accurate method of dental age estimation, but are time saving in their use. They are an excellent screening tool, particularly for post-mortem identification purposes, and for assessing variation from population norms in living individuals.The aim of this study was to test the precision and accuracy of three dental development charts (Schour and Massler, Blenkin and Taylor, and the London Atlas), used to estimate dental age of a sample of New Zealand juveniles between the ages of 5 and 18 years old (n=875).Percentage ‘best fit’ to correct age category and to expected chart stage were calculated to determine which chart was the most precise for the sample. Chronological ages were compared to estimated dental ages using a two-tailed paired t-test (P<0.05) for each of the three methods. The mean differences between CA and DA were calculated to determine bias and the absolute mean differences were calculated to indicate accuracy.The results of this study show that while accuracy and precision were low for all charts tested against the New Zealand population sample, the Blenkin and Taylor Australian charts performed best overall.