A Coloured Atlas of the Mandible and its Forensic Applications

Background: Skeletal remains assessment, typically conducted by forensic anthropologists and forensic dentists, aims to establish identity and determine the manner of death. The mandible is the most robust bone of the skull, distinguishable when fragmented, and commonly located detached from the cranium. This frequent detachment from the skull highlights its standalone value in forensic investigations, where it may be the only available evidence. Aims: This research aimed to identify the information obtainable from the assessment of the mandible to aid in forensic investigations, explore the current practices adopted by forensic experts, review and summarise existing literature, and develop resources to enhance the analysis and interpretation of mandibular evidence in forensic science. Methods: (1) A scoping review of peer-reviewed articles on the mandible in forensic science published before 2020 on PubMed, ScienceDirect, Scopus, and Latin American and Caribbean Health Sciences Literature (LILACS) was conducted; (2) a traditional literature review was performed to compile existing research on comparative dental and mandibular anatomy and trauma assessment; (3) a systematic review of peer-reviewed articles on biological profiling using the mandible was carried out on PubMed, ScienceDirect, Scopus, and LILACS; and (4) a 20-question online survey on JISC (2020) was designed to assess forensic dentists' and anthropologists' understanding of and current practices in evaluating the mandible; Results: (1) The scoping review found 235 articles, which can be classified into four main topics: biological profile (n=145), skeletal trauma (n=52), photography and handling remains (n=11), and comparative anatomy (n=6). (2) Insufficient literature on comparative dental and mandibular anatomy and trauma assessment, a lack of research on the mandibular anatomical variations across the Scottish wild mammals, and the utilisation of 2D images to explain traumas were observed. (3) Sex estimation was the most investigated element of the biological profile (n=94), followed by age (n=25), population affinity (n=5), and stature (n=1). Most of the studies followed metric analysis of the mandible (n=80). Inconsistent terminologies of the mandibular measurements were detected. (4) Forty-one forensic dentists and anthropologists participated in the survey, making up a response rate of 8.08%. Two-thirds of the participants considered the mandible valuable evidence in sex estimation, compared to around one-half in age or population affinity estimation. More than 95% of the surveyed forensic professionals believe that the mandible is not correlated with the subject’s stature. 71% of the experienced participants do not implement a guideline for assessing mandibular trauma. The accuracy rate of specimen identification, based on 2D images of a cat tooth, bear mandible, pig tooth, and U-shaped duck bone, ranged between 7.3% and 41.5%. Conclusion: The evidence extracted from the mandible is imperative for distinguishing the specimen's human or non-human origin. Evaluating trauma indicators on the mandible assists with the timing and mechanism of the trauma and probing for torture or human rights violations. Additionally, the mandible can be used to estimate the individual’s sex, age, and population affinity. However, the measurements require standardisation to improve communication, reporting, and reproducibility. Comprehensible tables of the anatomical variations of the dentitions and mandibles of mammals were produced along with a pocket guide of the mandibles of the Scottish Wild Land Mammals to optimise their identification by forensic practitioners, police officers, and the general public. Furthermore, this research proposed guides to facilitate the mandible's trauma assessment and biological profiling. Three-dimensional models were also crafted to present mandibular anatomy, trauma classifications, timing, mechanism, and sexually dimorphic features. A short video was also produced to enhance the understanding of fracture healing.