Automated estimation of chronological age from panoramic dental X-ray images using deep learning. (1st March 2022) - Milošević, Denis
Abstract: Age estimation is a key component in forensic analysis, be it in legal proceedings or archeological research. Current methods in forensic odontology are based on manual measurements of a wide array of morphometric parameters, typically from dental x-ray images, and occasionally from material remains. While those parameters follow a set progression during human development, thereby allowing current methods to precisely estimate the age of juveniles, estimation for adults and seniors proves to be more difficult. In this study, we explore the applicability of deep learning to the problem of chronological age estimation. We determine the best convolutional neural network model derived from state-of-the-art architectures, we determine the best performing model parameters using pretrained general-purpose vision model parameters as the starting point, and we perform ablation experiments to highlight which anatomical regions of the dental system contribute the most to the estimation. The proposed approach attains the lowest estimation error in literature for adult and senior subjects, which we verify on one of the largest datasets of panoramic dental x-ray images in literature. The dataset consists of 4035 panoramic dental x-ray images of male and female subjects with ages between 19 and 90 years. This study also evaluates the feasibility of the proposed model for age estimations of individual teeth, achieving an estimation error competitive with current methods while being fully automated. The estimation error is verified on our dataset of 76416 individual tooth images, which is the largest dataset to date in forensic odontology literature. Unlike current methods, dental alterations, decay, illnesses, or missing teeth do not pose a problem to the proposed model. With a median estimation error of 2.95 years for panoramic dental x-ray images and 4.68 years for individual teeth, and by deriving the model from state-of-the-art architectures, verifying those results on the largest dataset in forensic odontology literature and demonstrating the importance of different anatomical regions of the dental system for estimation, this study sets the baseline for future research of automated chronological age estimation in forensic odontology. Highlights: Age estimation of adults is a hard problem in forensic odontology. Only manual measurement methods are currently used in practice. This deep learning approach eclipses expert performance in a fraction of the time. The interpretability analysis gives new insight into anatomical changes due to age. The method is verified on the largest dataset in literature.