Three-dimensional imaging of human cutaneous forearm bite marks in human volunteers over a 4 day period.

INTRODUCTION: Human bite marks are often sustained during sexual, domestic or child abuse. Currently, analysis of these marks involves digital photography techniques along with an expert forensic odontologist opinion. Photographs often focus closely on the bite mark and give little context to the anatomical location of the injury. Due to variation in camera models and expertise of the photographer, photograph quality can affect its interpretation. Additionally, it can sometimes be days between injury and examination, allowing the injury pattern and colour to alter, making it harder to analyse.

AIM: To investigate if a 3D imaging technique, creating a time-lapse image of a bite mark in three dimensions, can provide context to the injury in terms of nature and location, and also allow analysis of the change in appearance of a bite mark over time.

METHOD: Participants had an experimental bite mark produced on their forearm by dental casts mounted on a dental articulator. The forearms were photographed immediately following the bite, and at intervals of 3, 6, 24, 48, 72 and 96 h. A DI3D(®) (Dimensional Imaging 3D) photogrammetry system and Autodesk Maya 2015(®) software was used to create a 3D animation from the images obtained. The clearest, long lasting bite mark injuries were selected for animation, enabling the 3D imaging technique to be used optimally.

RESULTS: 3D time-lapse animations were successfully created with the ability to be viewed on most electronic devices. With further refinement this technique could be valuable in a number of areas. We anticipate animations produced in this way to have significant benefit to the presentation of photographic evidence in a court setting, and in age estimation of injuries.