What every dentist must know about forensic odontology: An overview

 Buccal epithelial cells are a rich source for extracting DNA by polymerase chain reaction (PCR) amplification, which could be advantageous to blood sampling [1]. However, its use in forensic odontology is confined to cases in which attaining peripheral blood samples is not feasible. Currently, most PCR gender-typing systems rely on the amplification and electrophoretic separation of the amelogenin gene[2].

Gender determination of skeletal remains is fraught with uncertainty, especially in subadults[3]. Although dentitions and their measurements seem to be the most reliable method in age determination, odontometric analyses of canines[4–6], translucent dentin[7], dental cementum incremental lines[8], dental root surface[9], pulp/tooth area ratio[6,10–12] and periodontal diseases can also predict the gender (using different validation accuracy, Rank-N recognition rate, mean absolute difference, linear kappa coefficient)[13], and so is the morphology of palatal rugae in cases of   incineration and decomposition[14–16]. It is a useful adjunct for sex determination for identification of cadavers. Specifically, points associated with the third palatal rugae are the most immutable over a person's lifetime and hence can be used as a reference to evaluate the changes in teeth positions during orthodontic treatment. Periodontal recession is more accelerated in males than in females.  Teeth and prosthodontic restorations can resist high temperatures enough to aid in the identification process if the quality and/or availability of antemortem and postmortem dental records is acceptable[17–19]. Figure 1 describes main experiments in forensic odontology.

Figure 1. Clustered word cloud showing the basic research areas in forensic odontology

Radiographic image of the frontal sinus, the infraorbital and the mental foramen position as indications of mouth width may also be useful in edentulous skulls[20]. Cheiloscopy (lip morphology and thickness) and smile photograph analysis of elevations and depressions that form a characteristic pattern on the external surface of the lips are also used to determine age and gender in forensic dentistry[2,14,21–23]. Because teeth can be an important deposit of exogenous substances accumulated both in the pulp and in the calcified tissues, they are an invaluable source of data from a toxicological point of view[24].

Substantial postmortem changes elude accurate estimate of the time of death. The recent application of histological techniques is proving to be an increasingly valuable tool in forensic research. Early post-mortem examination shows that the initial epithelial changes observed were homogenization and eosinophilia while cytoplasmic vacuolation, shredding of the epithelium, ballooning, loss of nuclei and suprabasilar split were noticed after one day of the time of death. Therefore, the histological changes in the gingival tissues may be useful in estimating the time of death in the early post-mortem period[18].

Because DNA can be amplified by PCR from a blood sample, dental pulp or other tissues, PCR is widely used in forensic sciences. It was demonstrated to be 100% reliable when used to assess the gender of teeth which had been heated at 100°C for 15 minutes. Teeth can resist higher temperature for longer times if they are submerged or impacted in gnathic bones, rendering them a rich source for DNA extraction[25,26].

Forensic odontology uses the input of every generalizable finding the dental research introduces[27–32]. However, forensic odontology cannot be useful without general practitioner, prosthodontists, orthodontists and all clinical dentists, regardless of their specialties, being fully aware of the need for keeping permanent and reliable dental records[33]. Not only does this include dental impressions and gypsum cast, but it encompasses all digital photos, intraoral and extraoral radiographs, panoramic tomography, CBCT, and TMJ imaging sorted chronologically. If saving blocks and casts need space, they can be digitized. However, the need for old-fashioned physical records is expected to be minimal with the popularity of the use of digital scanners and computational applications[34]. Dentists and maxillofacial surgeons should also familiarize themselves with the medicolegal legislature and volunteer to cooperate with departments of forensic medicine when needed. Incidental findings may also reshape our understanding of oncological diseases and their infiltrations[35].

Notes: None

Acknowledgements: The author would like to extend his appreciation to the Researchers Supporting Project number (RSP2022R480) at King Saud University, Riyadh, Saudi Arabia.

Funding resources: None

Conflict of interest: The authors declare that there is no conflict of interest.