Bitemark analysis using an intraoral 3d scanner (iTero®): experimental study on human skin

Bites can leave unique marks on the skin that may be useful to identify the perpetrator of a crime. Standard bitemark analysis is currently based on visual comparison, often conducted using photographs, and involving several operator-dependent measurements, but recently an experimental method using three-dimensional (3D) scanning and computer software to objectively analyze bitemarks on dentistry wax has been proposed. In the present study the same method was applied using 12 complete (upper and lower dental arches) plaster models of human dentitions to experimentally produce 24 bitemarks on human skin. The plaster models and the bitemarks were scanned using iTero® 3D scanner. Both the dental models and bitemarks were processed with MeshMixer™ software. For quantitative comparison, bitemarks were compared to their corresponding dentitions using CloudCompare software. A control group involved comparisons between bitemarks and random dentitions. Upper and lower dental arches of coincident comparisons were also compared to assess potential differences. The results revealed different distribution curve trends when comparing bitemarks to the biter dentition versus non-coincident dentitions. Instead, no difference emerged between upper and lower dental arches. This method shows the potential of 3D scanning distinguishing between matched and non-matched dentitions under experimental conditions. Moreover, data from the 3D reconstruction of the dentition and the bitemark remain available for further in-depth study for second opinion. The promising results of digital comparisons between bitemarks and dental models suggest that this method could lead to a more accurate and objective approach to bitemark analysis in the future. However, further validation is required before forensic application.