Demirjian’s method is unsuitable for dental age estimation

Excerpt

We read the article titled “Is Demirjian’s original method really useful for age estimation in a forensic context?” published in your journal [1]. We find that the study is well conducted but the title of this study is misleading. From the title it looked like the study had tested the Demirjian’s method on different population groups or that the authors had undertaken a review of the literature on the existing studies on Demirjian’s method, but the aim of the study was to assess the reliability of Demirjian’s method on a sample of Portuguese children. This is not reflected in the title. This study concluded that the method overestimated the age of both Portuguese boys and girls. While this study adds important information to the existing literature on the application of Demirjian’s method, the findings in this study are not a new; an earlier study on the Portuguese population also reported overestimation of age in both genders [2]. The use of Demirjian’s method has been questioned over several years as published studies in different population groups have consistently reported overestimation of age. The appropriate way to assess population differences is by applying Demirjian’s method on different population groups with stringent data collection and analysis taking into account of several factors in age estimation including number, age, and gender of the samples included in the analysis. Another approach is to conduct a systematic review of the literature on the studies that used Demirjian’s method. Both of these procedures have already been carried out. A study by Liversidge found group differences in the estimated age when using the Demirjian method on subject data from Europe, Middle East, Africa, India, China, and South America. The study concluded that Demirjian’s dental maturity method is inappropriate to assess population differences in dental maturity [3]. The first systematic review and meta-analysis on the studies that utilized Demirjian’s method was published by the DARLInG team in early 2013. We identified 34 studies from 22 countries that satisfied the inclusion criteria and found that Demirjian’s method on average overestimated the age by 6 months, sometimes up to 3 years [4]. Following this, another systematic review was published in the same year, which also reported a similar outcome. We later found that their review had several errors including the selection of articles and misinterpretation of data that had been subsequently published as comments to the article [5]. The use of Demirjian’s method for dental age estimation has always been problematic and several investigators have had difficulty in interpreting their data. The overestimation of age is just the beginning of the issues associated with this method. The most important area is that the statistical approach utilized to derive maturity scores is not understood. It is clear that the method is not designed to estimate dental age, which Demirjian and co-workers clearly mention in their original paper. They also warned about the existence of population differences in dental maturity [6]. Despite these warnings, the use of the method continues in different populations; the most recent was on a Tunisian population published in early 2016 [7]. There are several factors that determine the accuracy of the estimated age. While it has been shown physiological maturity differs with age, gender, and ethnicity, the additional influences of secular trend, socio-economic status, and nutritional changes are yet to be fully explored. We agree with the authors that the Demirjian’s dental maturity data cannot be used to estimate age and this practice should be totally abandoned. We have contacted Prof. Arto Demirjian and Prof. Harvey Goldstein, authors of the original study, to gain insight into the statistical approach used in their study to be able to conduct a detailed analysis of the Demirjian method and the reason why it is no longer suitable. This will be published as a separate paper. …