Examination of regressive features of third molars for the purpose of age assessment in the living by means of rescaled regression analyses

A systematic overview of dental methods for age assessment in living individuals: from traditional to artificial intelligence-based approaches

Dental radiographies have been used for many decades for estimating the chronological age, with a view to forensic identification, migration flow control, or assessment of dental development, among others. This study aims to analyse the current application of chronological age estimation methods from dental X-ray images in the last 6 years, involving a search for works in the Scopus and PubMed databases. Exclusion criteria were applied to discard off-topic studies and experiments which are not compliant with a minimum quality standard. The studies were grouped according to the applied methodology, the estimation target, and the age cohort used to evaluate the estimation performance. A set of performance metrics was used to ensure good comparability between the different proposed methodologies. A total of 613 unique studies were retrieved, of which 286 were selected according to the inclusion criteria. Notable tendencies to overestimation and underestimation were observed in some manual approaches for numeric age estimation, being especially notable in the case of Demirjian (overestimation) and Cameriere (underestimation). On the other hand, the automatic approaches based on deep learning techniques are scarcer, with only 17 studies published in this regard, but they showed a more balanced behaviour, with no tendency to overestimation or underestimation. From the analysis of the results, it can be concluded that traditional methods have been evaluated in a wide variety of population samples, ensuring good applicability in different ethnicities. On the other hand, fully automated methods were a turning point in terms of performance, cost, and adaptability to new populations.

Preliminary analysis testing the accuracy of radiographic visibility of root pulp in the mandibular first molars as a maturity marker at age threshold of 18 years

Forensic age estimation, after completion of third molar mineralization, regressive features such as apposition of secondary dentin, which is seen as narrowing of the pulp space in the radiographs, can be used as an alternative. In the present study, we explored the radiographic visibility of the root pulp of mandibular first molars using stage classification of Olze et al. (Int J Legal Med 124(3):183-186, 2010) in a sample of 901 orthopantomograms (404 males and 497 females) of south Indian origin with age ranging from 14 to 22 years. Descriptive statistics for the stages according to age was performed for both sexes separately. The strength and direction of the relationship between the chronological age and pulp visualization stages was tested using spearman's rho correlation statistics. The relationship between age and stage attainment showed statistical significance for both sexes. A strong, positive correlation was seen between the stage and chronological age. All males and females presenting stage 0 of root pulp visibility were younger than 18 years. If stage 1 is determined, it is highly possible that an individual regardless of sex is younger than 18 years. Stage 2 was attained in 79.6% males and 83.1% females who were at least 18 years. One hundred percent males and 92.8% females with stage 3 were at least 18 years. The accuracy of this method in mandibular first molars for estimating age threshold of 18 years ranged from moderate to high. However, it is recommended to use this method in conjunction with other age estimation methods.