Assessment of Accuracy of Digitally Generated Overlays Compared to Conventional Overlays For Simulated Bitemark Analysis on Cheese Blocks

Abstract

Background: The bite injury or bite mark is examined as corroborative evidence in serious crimes such as rape, murder, robbery, and other forms of physical and sexual violence. The goal of this study was to comparatively evaluate the accuracy of overlays made with a digital, two-dimensional method compared to those made by directly tracing bite marks and using bite mark images obtained with a photocopier. Materials and Methods: A total of 61 participants were included in the study, of whom 31 were males with ages ranging between 18-65 years and 30 were females. The simulated bitemarks on the cheese block were used to prepare three sets of overlays, first by the way of hand-tracing, followed by a photocopying technique and a third set of overlays prepared using computer software called Adobe Photoshop version CS6 on a personal computer. Each pair of overlays and the study cast was then matched using 5-point criteria given by the ABFO guidelines, and a score between 0-3 was assigned to each observation. Results: The overall scores obtained in each group (A-hand-tracing, B-photocopy, C-digital method) were then compared amongst themselves for associations. By applying the Kruskal Wallis ANOVA test, the manual technique had a 29.5% positive matching rate, in photocopying method 32.8%, and the digital overlay 72.1%, which was significant. Conclusion: In conclusion, the digital overlay method outperformed the hand-tracing and photocopying methods in terms of minimizing the subjective errors and was found to be the most precise and dependable method.