Combining the third molar mineralization to further improve the accuracy of the Kvaal’s method in dental age estimation of subadults in northern China

Abstract

The morphological changes based on deposition of secondary dentin and mineralization of the third molar have been proven to be related to chronological age. However, Kvaal’s method on the theory of deposition of secondary dentin was controversial with respect to dental age estimation in the recent research. The aim of this study was to combine parameters of Kvaal’s method with relatively high correlation coefficients and mineralization stages of the third molar to improve the accuracy of predicting the dental age of subadults in northern China. A total of 340 digital orthopantomograms of subadults aged from 15 to 21 years were analyzed. A training group was used to test the accuracy of the original Kvaal’s method and establish novel methods for subadults in northern China. A testing group was used to compare the accuracy of the newly established methods with the Kvaal’s original method and published method specifically used in northern China. To increase the feasibility of our estimation model, we combined the mineralization of the third molar to build a combined specific formula. The results showed that the combined specific model increased the coefficient of determination to 0.513 and the standard error of the estimate was reduced to 1.482 years. We concluded that the combined specific model based on deposition of secondary dentin and mineralization of the third molar could improve the accuracy of dental age assessment of subadults in northern China.