Machine learning-based classification of population affinity in two North Indian populations using morphological dental traits-Forensic implications.

Forensic odontology is a sub-discipline of forensic science, that deals with examination, handling and demonstration of dental evidence for personal identification. Morphological dental traits (MDTs) can be used for the classification of population groups that may play a vital role in forensic identification. The objective of the present study was to classify the population affinity in two population groups on the basis of the MDTs using Machine Learning (ML) models and to comparatively analyze which ML model is the best for the classification. In the present study, 434 participants (207 Males and 227 females) ranging in age from 18 to 40 years were enrolled from two major population groups of North India i.e. the Khasas and the Kolis. Dental casts of the participants were prepared. MDTs were observed and noted in comma separated value (csv) excel sheet. The feature selection was done using Recursive Feature Elimination (RFE) to identify the most informative morphological trait of teeth for population classification. Machine learning models were trained on the prevalence and incidence of these MDTs, including Support Vector Machine (SVM), Logistic Regression (LR), Decision Tree (DT), Random Forest (RF), and Gradient Boosting (GBM); the models achieved accuracy rates of 74.7%, 75.8%, 64.37%, 68.97%, and 64.37%, respectively. Of all the models, logistic regression (LR) has the highest accuracy (75.8%), followed by SVM. Further, ROC-AUC and F1 score analysis confirmed Logistic Regression as the best-performing model, outperforming Decision Tree and Gradient Boosting which both recorded the lowest accuracy of 64.3%. The present study demonstrates how machine learning approaches can be used to support population affinity estimation using dental features. Findings of the present study may be useful in disaster victim identification, crime scene investigation, and other forensic examinations where dental remains are presented for forensic analysis.