Digital Analysis of Experimental Human Bitemarks: Application of Two New Methods

Abstract

Bitemark determination in forensic odontology is commonly performed by comparing the morphology of the dentition of the suspect with life-sized photographs of injury on the victim's skin using transparent overlays or computers. The purpose of this study is to investigate the suitability of two new different methods for identification of bitemarks by digital analysis. A sample of 50 volunteers was asked to make experimental bitemarks on the arms of each other. Stone study casts were prepared from upper and lower dental arches of each volunteer. The bitemarks and the study casts were photographed; the photos were entered into the computer and Adobe Photoshop software program was applied to analyze the results. Two methods (2D polyline and Painting) of identification were used. In the 2D polyline method, fixed points were chosen on the tips of the canines and a straight line was drawn between the two fixed points in the arch (intercanine line). Straight lines passing between the incisal edges of the incisors were drawn vertically on the intercanine line; the lines and angles created were calculated. In the painting method, identification was based on canine-to-canine distance, tooth width and the thickness, and rotational value of each tooth. The results showed that both methods were applicable. However, the 2D polyline method was more convenient to use and gave prompt computer-read results, whereas the painting method depended on the visual reading of the operator.

Biomechanical Factors in Human Dermal Bitemarks in a Cadaver Model*

“…Only a few studies have examined distortional factors with regard to skin (24)(25)(26)(27)(28)(29). The authors of these studies urged further investigation and acknowledged potential for discrepancies.…”

Experimental Study of Bite Mark Injuries by Digital Analysis

“…Two light sources from two directions were fixed to avoid any shadow in the photographs. Several photos were taken of each bite mark to select the most appropriate photograph for the comparison procedure (14). …”

Bite Marks as Physical Evidence from the Crime Scene-An Overview

“…Alternatively they may be found on the suspect, left by the victim during self defense. The quality and accuracy of a bite mark are dependent on numerous factors, including time-dependent changes, where the bite mark was found, damage on soft tissue, dental similarity among individuals [7], and poor photography [8][9][10][11], impressions or measurements. If a bite mark is only represented as a bruise it is often extremely difficult to detect any individual characteristics.…”