3D printing and CBCT anatomical reproducibility assessment in forensic scenarios

The scientific community highlighted the relevance of 3D physical models since the beginning of the XXI century, complementary to three-dimensional(3D) digital volume by computer tomography, to support court discussions on medico-legal issues. The recreation of 3D evidence can be an important tool for investigators and experts, providing a better understanding of the causes and circumstances of the events involved in a crime.

The present study aims to assess the reproducibility of 3D printed and 3D tomographic volumes generated from mandibles following simulated forensic injuries, highlighting the recreation of crime tools.

Concerning the study design presented, data collection was performed in three phases. Nine simulated injuries of forensic interest were selected (phase1) and all the mandibles were scanned tomographically, individually, by Cone Beam Computed Tomography CBCT (phase 2). Then, in phase 3, the DICOM images were used for 3D printing with the Ender 3® printer by the Fused Deposition Modeling (FDM) technique. The data analysis followed two procedures: the comparison between the artificial mandible and 3D tomographic volume (AT) and the comparison between the artificial mandible and 3D printed volume, or the copy (AC). Data were analyzed using T-Student and ICC tests and presented in Bland-Altman plots.

The analogic technique applied in 3D printed volume, when compared with computerized technique, using 3D digital images and measurement, showed to be accurate and reproducible. Further studies are needed in search of standardization for three-dimensional measurements in digitized and printed volumes.