Feasibility and validation of virtual autopsy for dental identification using the Interpol dental codes

The radiographic diversity of dental patterns among 7219 young individuals-a contribution to disaster victim identification

The diversity of dental patterns is a fundamental topic in disaster victim identification. The current scientific literature, however, is scarce of data regarding young individuals. This study aimed to assess the radiographic diversity of dental patterns, considering missing, unrestored, and filled teeth in young individuals. The sample consisted of 7219 panoramic radiographs of individuals between 12 and 22.9 years. The permanent teeth, except third molars, were coded as missing, unrestored, or filled and odds ratios (OR) were calculated based on sex, dental arch, and age. The sex-combined sample had 1.116 distinctive dental patterns. "All unrestored" teeth was the most common pattern (OR: 0.437) followed by the sequence of unrestored teeth except restored mandibular first molars (OR: 0.021). Females had more distinctive dental patterns than males (p < .001), while males had more unrestored teeth (p < .001). In the age category of 12-12.9 years, the OR for finding a distinctive dental pattern was 11%, while in the age category of 22-22.9 years it increased to 58%. On the other hand, the OR for "all unrestored" gradually decreased according to age (74% in the younger category, and 23% in the older age category). The distinctiveness of dental patterns among young individuals is affected by the predominance of unrestored teeth. However, registering a single filled tooth in a remaining unrestored dentition can reduce exponentially the probability of finding an identical pattern of missing, unrestored and filled teeth.

Radiographic morphology of canines tested for sexual dimorphism via convolutional-neural-network-based artificial intelligence

The permanent left mandibular canines have been used for sexual dimorphism when human identification is necessary. Controversy remains whether the morphology of these teeth is actually useful to distinguish males and females. This study aimed to assess the sexual dimorphism of canines by means of a pioneering artificial intelligence approach to this end. A sample of 13,046 teeth radiographically registered from 5838 males and 7208 females between the ages of 6 and 22.99 years was collected. The images were annotated using Darwin V7 software. DenseNet121 was used and tested based on binary answers regarding the sex (male or female) of the individuals for 17 age categories of one year each (i.e. 6-6.99, 7.7.99… 22.22.99). Accuracy rates, receiver operating characteristic (ROC) curves and confusion matrices were used to quantify and express the artificial intelligence's classification performance. The accuracy rates across age categories were between 57-76% (mean: 68%±5%). The area under the curve (AUC) of the ROC analysis was between 0.58 and 0.77. The best performances were observed around the age of 12 years, while the worst were around the age of 7 years. The morphological analysis of canines for sex estimation should be restricted and allowed in practice only when other sources of dimorphic anatomic features are not available.

Detecting missing teeth on PMCT using statistical shape modeling

The identification of teeth in 3D medical images can be a first step for victim identification from scant remains, for comparison of ante- and postmortem images or for other forensic investigations. We evaluate the performance of a tooth detection approach on mandibles with missing parts or pathologies based on statistical shape models. The proposed approach relies on a shape model that has been built from the full lower jaw, including the mandible and teeth. The model is fitted to the target, resulting in a reconstruction, in addition to a label map that indicates the presence or absence of teeth. We evaluate the accuracy of the proposed solution on a dataset consisting of 76 target mandibles, all extracted from CT images and exhibiting various cases of missing teeth or other cases, such as roots, implants, first dentition, and gap closure. We show an accuracy of approximately 90% on the front teeth (including incisors and canines in our study) that decreases for the molars due to high false-positive rates at the wisdom teeth level. Despite the drop in performance, the proposed approach can be used to obtain an estimate of the tooth count without wisdom teeth, tooth identification, reconstruction of the existing teeth to automate measurements taken as part of routine forensic procedures, or prediction of the missing teeth shape. In comparison to other approaches, our solution relies solely on shape information. This means it can be applied to cases obtained from either medical images or 3D scans because it does not depend on the imaging modality intensities. Another novelty is that the proposed solution avoids heuristics for the separation of teeth or for fitting individual tooth models. The solution is therefore not target-specific and can be directly applied to detect missing parts in other target organs using a shape model of the new target.

Validity of postmortem computed tomography for use in forensic odontology identification casework

Forensic Odontology (FO) identification compares antemortem (AM) and postmortem (PM) dental datasets and is widely accepted as a primary identifier. Traditionally, a PM dental examination is undertaken in the same manner as a dental examination conducted for a living patient. Recently, the increased forensic application of computed tomography (CT) offers an alternative source of PM data. While charting from PMCT is widely accepted as less accurate, the impact on reconciliation is unknown. This study aims to determine if reconciliation outcome differs when PM dental data is collected from PMCT, compared with conventional PM examination. PMCT data was reviewed for 21 cases previously completed using conventional PM dental examination. Operators blinded to original identification outcomes charted from CT images before comparing to AM data to form an opinion regarding identity. Opinions formed were compared with original identification outcomes. Differences in PM dental charting between the two methods and the evidentiary value of AM and PM datasets were assessed to determine driving factors of differences in identification outcome. Compared to conventional PM dental examination, PMCT examination resulted in similar or less certain identification outcomes. Discrepancies in outcome were driven by the quality of AM and PM datasets rather than inaccuracies in charting from PMCT. Based on the results of this study, both conventional and PMCT methods of PM dental examination can reach similar identification outcomes. However, operators remained more certain in establishing identity when conducting conventional PM dental examinations especially when AM data was lacking.

The Role of an Endodontist in Victim Identification: A Narrative Review on Forensic Endodontics

This narrative review highlights the role of endodontists and the significance of various dental tools in forensic dentistry. An online search was conducted in peer-reviewed journals, including MEDLINE (Ovid), PubMed, Web of Science, Scopus, and Google Scholar databases, to retrieve studies regarding "the role of an endodontist in victim identification using different tools". The searches used controlled vocabulary and free-text terms. Articles written in English and published from 1923 to 2023 were selected. An essential stage in forensic dentistry is dental identification of the dead person and is regarded as an initial step for both judicial and humanitarian purposes if fingerprint records are missing or the remains have undergone significant changes. Endodontists should be aware of all available dental tools that aid in identification. The four fundamental tools for identification are dental radiographs, hard and soft dental structures, and dental materials. Dental radiographs provide a substantial nondestructive record for estimating age and sex. Moreover, maxillofacial hard and soft structures provide important tools for individual identification as they are considered the strongest structures in the human body and can withstand severe chemical and temperature changes. In addition, endodontic and restorative materials can be identified under different conditions and serve as excellent forensic identification measures.

Teledentistry and Forensic Odontology: Qualitative Study on the Capacity of Implementation

The postmortem identification of people without an identity is performed either by using DNA, dental charts, or fingerprints (until advanced decomposition prevents their study). The lack of forensic dentists who can conduct identifications lead us to reflect on the use of digital technology in this area. The aim of this study was to validate the organizational capacity of using teledentistry for the identification of bodies in a forensic medicine department. A mixed observational study was conducted on 55 cases between July 2020 and February 2021 in the Forensic Medicine and Thanatology Department of Montpellier University Hospital. The protocol was structured in five steps: an initial interview with the agent (a forensic autopsy technician/caregiver specialized in forensic medicine), regarding the idea they had in terms of using telemedicine in their daily practice; agent training in the telemedicine system; realization of a clinical examination using an intra-oral camera by the agent; data analysis by a dental surgeon; final interview with the agent. The study was conducted on 55 subjects. The average age was 54 years old, with more than two-thirds of the patients being male (69%). The videos had an average duration of 29 min. There was an increase in visit duration when rigidity was high; this was also the case when there were many dental specificities in the oral cavity. The quality of the videos was either good or excellent. This study showed that remote identification could be considered as a new non-invasive identification tool. Many features were analyzed to create a training guide for forensic institutes.

The radiographic diversity of dental patterns for human identification - Systematic review and meta-analysis

This study aimed to revisit the scientific literature related to the diversity of dental patterns observed in radiographs. The rationale was to find evidence to support dental human identifications. A systematic review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). Strategic search was accomplished in five electronic data sources (SciELO, Medline/Pubmed, Scopus, Open Grey and OATD) were searched. The study model of choice was observational analytical cross-sectional. The search resulted 4.337 entries. The sequential screening based on title, abstract and full-text reading led to 9 eligible studies (n = 5.700 panoramic radiographs) published between 2004 and 2021. Studies from Asian countries were predominant (e.g., South Korea, China, and India). All the studies showed low risk of bias (measured according to the Johanna Briggs Institute's critical appraisal tool for observational cross-sectional studies). Morphological, therapeutic, and pathological identifiers were charted from radiographs to create dental patterns across studies. Six studies (n = 2.553 individuals) had similar methodology and outcome metrics and were included in the quantitative analysis. A meta-analysis was performed and revealed a pooled diversity of the human dental pattern of 0.979 combining maxillary and mandibular teeth. The additional subgroup analysis with maxillary and mandibular teeth have a diversity rate of 0.897 and 0.924, respectively. The existing literature shows that human dental patterns are highly distinctive, especially if morphological, therapeutic and pathological dental features are combined. The diversity of dental identifiers found in the maxillary, mandibular and combined arches is hereby corroborated by this meta-analyzed systematic review. These outcomes support applications for evidence-based human identification.

Diagnostic performance of convolutional neural networks for dental sexual dimorphism

Convolutional neural networks (CNN) led to important solutions in the field of Computer Vision. More recently, forensic sciences benefited from the resources of artificial intelligence, especially in procedures that normally require operator-dependent steps. Forensic tools for sexual dimorphism based on morphological dental traits are available but have limited performance. This study aimed to test the application of a machine learning setup to distinguish females and males using dentomaxillofacial features from a radiographic dataset. The sample consisted of panoramic radiographs (n = 4003) of individuals in the age interval of 6 and 22.9 years. Image annotation was performed with V7 software (V7labs, London, UK). From Scratch (FS) and Transfer Learning (TL) CNN architectures were compared, and diagnostic accuracy tests were used. TL (82%) performed better than FS (71%). The correct classifications of females and males aged ≥ 15 years were 87% and 84%, respectively. For females and males < 15 years, the correct classifications were 80% and 83%, respectively. The Area Under the Curve (AUC) from Receiver-operating Characteristic (ROC) curves showed high classification accuracy between 0.87 and 0.91. The radio-diagnostic use of CNN for sexual dimorphism showed positive outcomes and promising forensic applications to the field of dental human identification.

Dental characteristics associated with methamphetamine use: analysis using forensic autopsy data

Background

Little is known regarding the oral conditions in nonelderly methamphetamine users, such as the presence of dental caries and periodontitis. We aimed the oral conditions between methamphetamine users and non-users stratified by age groups.

Methods

In this cross-sectional study, computed tomography images were obtained from 3,338 decedents at two forensic medicine departments in Japan. Decedents aged > 20 or ≤ 64 years were included in the study and categorised into methamphetamine-detected (MA) and undetected (control) groups based on toxicological examinations. Decedents in the MA and control groups were matched for age and sex in a 1:4 ratio. The matched pairs were further categorised into young adults (20–44 years) and middle-aged adults (45–64 years). Oral characteristics, including the decayed, missing, and filled teeth (DMFT) index; periodontitis; distributional patterns of each tooth condition; and occlusal status, were compared between the MA and control groups for each age category. Among 3,338 decedents, 37 young and 55 middle-aged adults in the MA group were matched with 148 and 220 adults in the control group, respectively.

Results

In the young adult group, methamphetamine use was significantly associated with higher DMFT index (mean [standard deviation], 14.2 [7.6] vs 11.0 [6.1]; p = 0.007), smaller number of filled teeth (2.8 [2.9] vs 5.3 [4.0]; p = 0.001), higher proportion of periodontitis (39.0% vs 6.8%; p < 0.001), and lower proportion of occlusal support (54.1% vs 81.1%; p = 0.001). Young adult methamphetamine users tended to have untreated decayed canines and molars and missing molars. These findings were similar to those in middle-aged adults except the tendency to have missing maxillary incisors.

Conclusions

Nonelderly methamphetamine users had distinctive oral characteristics that may help screen for methamphetamine abuse through dental examinations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02182-6.

Forensic imaging: a powerful tool in modern forensic investigation

Forensic imaging is a non-invasive examination process during the forensic investigation. It is mainly used in forensic pathology as an adjunct to the traditional autopsy. In the past two decades, forensic imaging has been vigorously developed by forensic experts from computed tomography (CT) to multiple augmented techniques through CT and magnetic resonance imaging (MRI). The application field of forensic imaging has also been broadened as its advantages are recognised by more forensic practitioners. In addition to the forensic pathology, this technique has been used in other forensic disciplines, including forensic anthropology, forensic odontology, forensic ballistics and wildlife forensics, etc. This article reviews the development of forensic imaging as the practice and research development in different forensic disciplines based on the relevant literature analysis.

VIRDENTOPSY: Virtual Dental Autopsy and Remote Forensic Odontology Evaluation

The identification of human remains relies on the comparison of post-mortem data, collected during the autopsy, with the ante-mortem data gathered from the missing persons' reports. DNA, fingerprints, and dental data are considered primary identifiers and are usually collected during any human identification process. Post-mortem dental data should be collected and analyzed by forensic odontologists, as a dental autopsy must not be confused with a dental examination. The virdentopsy project was inaugurated in 2020, during the COVID-19 pandemic, to allow the correct process of human remains by collecting dental data from teeth and jaws, which was then transmitted to forensic odontologists remotely for an expert opinion to achieve a generic profile of the unidentified human remains. The post-mortem dental biography is paramount to narrow the search for compatible missing persons but requires knowledge and experience of forensic odontologists. The virdentopsy process uses radiographic imaging (periapical X-rays, CT scans, panoramics), 2D/3D photos and video recording, photogrammetry documentation, 3D scanning, and live streaming where possible. This registered term was created by merging the terms "virtual" and "dental autopsy" but with no commercial benefits. The proposed process combines research topics under the field of the human rights of the dead and humanitarian forensic odontology services. It should enhance and accelerate the human identification process of the deceased, age estimation of the living, analysis of panoramic X-ray images, and be an educational tool for remote live training in forensic odontology and anatomy of skulls. This paper presents an overview of the virdentopsy process in the field of forensic odontology as a remote consultation as well as an educational tool for undergraduates and postgraduates.

Potential use of deep learning techniques for postmortem imaging

The use of postmortem computed tomography in forensic medicine, in addition to conventional autopsy, is now a standard procedure in several countries. However, the large number of cases, the large amount of data, and the lack of postmortem radiology experts have pushed researchers to develop solutions that are able to automate diagnosis by applying deep learning techniques to postmortem computed tomography images. While deep learning techniques require a good understanding of image analysis and mathematical optimization, the goal of this review was to provide to the community of postmortem radiology experts the key concepts needed to assess the potential of such techniques and how they could impact their work.

Personal identification with orthopantomography using simple convolutional neural networks: a preliminary study

Forensic dental examination has played an important role in personal identification (PI). However, PI has essentially been based on traditional visual comparisons of ante- and postmortem dental records and radiographs, and there is no globally accepted PI method based on digital technology. Although many effective image recognition models have been developed, they have been underutilized in forensic odontology. The aim of this study was to verify the usefulness of PI with paired orthopantomographs obtained in a relatively short period using convolutional neural network (CNN) technologies. Thirty pairs of orthopantomographs obtained on different days were analyzed in terms of the accuracy of dental PI based on six well-known CNN architectures: VGG16, ResNet50, Inception-v3, InceptionResNet-v2, Xception, and MobileNet-v2. Each model was trained and tested using paired orthopantomographs, and pretraining and fine-tuning transfer learning methods were validated. Higher validation accuracy was achieved with fine-tuning than with pretraining, and each architecture showed a detection accuracy of 80.0% or more. The VGG16 model achieved the highest accuracy (100.0%) with pretraining and with fine-tuning. This study demonstrated the usefulness of CNN for PI using small numbers of orthopantomographic images, and it also showed that VGG16 was the most useful of the six tested CNN architectures.

Odontological identification dental charts based upon postmortem computed tomography compared to dental charts based upon postmortem clinical examinations

Since the beginning of this century, the use of postmortem computed tomography (PMCT) in forensic autopsies has increased. In this study we examined how similar dental charts created using PMCT as a solitary examination mode were to dental charts created using the conventional method of a clinical inspection including intraoral radiographs. A total of 100 previously performed dental identification cases were retrospectively included in the study. For each case, a dental chart was created solely based upon PMCT. The PMCT based dental chart was subsequently compared with the chart created from the previous conventional identification examination. Based upon the accuracy, sensitivity and specificity values PMCT performed very well compared to the conventional method in the identification concerning presence or absence of teeth, the presence of crowns, bridges and endodontic treatments as well as the presence and types of fillings. PMCT performed poorly concerning the extension of fillings and identification of small, tooth-colored fillings. The use of PMCT is a valuable supplement to the conventional methods available for forensic odontologists and may be of great value for initial screening in mass fatalities.

Dental Cingulum and Position of Fixed Orthodontic Appliance as Source of Morphological and Therapeutic Identifiers: An Unusual Case Report

Orthodontic records, such as photographs, radiographs, and dental casts, provide information useful for identification purposes because it may reveal important morphological, therapeutic, and pathological dental identifiers. Among these identifiers, the type and position of orthodontic appliances figure as distinctive tools for human identification. In this context, the present study aims to report an uncommon case of identification of a putrefied body, found near to a forest region in Brazil. The postmortem (PM) examination showed that the victim had part of a fixed orthodontic appliance installed in the maxillary and mandibular dental arches. To identify the body, relatives of the potential victim presented orthodontic examinations containing panoramic radiography and photographs of the orthodontic treatment. The body was identified based on the analysis of the radiographs and photographs that confirmed the presence of the orthodontic appliances observed PM. More specifically, the identification was supported by the analysis of bracket bonding position of the maxillary and mandibular incisors and the presence of distinctive morphological traits of the canines and incisors, as well dental roots observed radiographically. The present case highlights the importance of orthodontic records as a source of morphological dental identifiers for cases in which only unrestored teeth are available.

Post-mortem computed tomography as part of dental identification - a proposed guideline

PURPOSE

This paper presents a proposed guideline for the use of post-mortem computed tomography (PMCT) during forensic dental identification. Currently, whole-body PMCT is widely used prior to autopsies for the diagnosis of fractures, organ changes, hemorrhages, and for the localization of foreign bodies, but it may also facilitate the odontological identification process in single cases and in cases involving multiple fatalities. Several studies have described the use of PMCT in forensic odontological work, but we have not found any comprehensive set of guidelines on how to perform a forensic odontological examination using PMCT. The aim was to develop guidelines for creating post-mortem dental charts during forensic odontological identification examinations using the standard functions of PMCT.

METHODS

A proposed guideline was developed from 15 selected cases examined at the Section of Forensic Pathology, Department of Forensic Medicine at the University of Copenhagen in Denmark from October 2011 to May 2012. Using the functionalities and three-dimensional (3D) reconstructions of OsiriX DICOM-viewer software (Pixmeo Sarl, Bernex, Geneva, Switzerland) we adjusted the contrast and brightness settings and developed a proposed guideline for creating PMCT-based dental charts. A four-step guideline was produced.

CONCLUSION

In our casework, we are currently using the guidelines proposed herein. The use of PMCT has allowed us to target our clinical examinations, greatly improving their efficiency. Furthermore, PMCT allows the storage of data for later documentation and research. Further research is needed to validate the proposed guideline.

Quantification of odontological differences of the upper first and second molar by 3D-3D superimposition: a novel method to assess anatomical matches

PURPOSE

The introduction of modern 3D image acquisition systems has enabled researchers to develop novel procedures for personal identification. The present study aimed to assess differences between dental scans belonging to the same or different subjects, through an innovative 3D-3D superimposition and registration method.

METHODS

Twelve subjects (6 males and 6 females) with pre- and post-orthodontic treatment dental casts were recruited. A 3D scan from each cast was obtained through a laser scanner and the 3D model of the upper first and second molar on the post-treatment cast was superimposed on the pre-treatment scan, for a total of 12 matches and 100 mismatches. Point-to-point RMS (root mean square) distance was then calculated. Student's t test verified possible statistically significant differences according to group (matches/mismatches; p < 0.05).

RESULTS

In case of matches, on average the point-to-point distance RMS was 0.29 mm (SD: 0.08 mm), while it was 0.94 mm (SD: 0.30 mm) for mismatches, with a statistically significant difference (p < 0.001).

CONCLUSIONS

Results show that the novel procedure was able to distinguish matches from mismatches through an RMS threshold (0.50 mm): a possible method for personal identification is described, which needs to be verified through the application to a larger sample of casts.

Comparing dental identifier charting in cone beam computed tomography scans and panoramic radiographs using INTERPOL coding for human identification

According to INTERPOL, the comparison of antemortem and postmortem dental identifiers is a scientifically reliable approach for human identification. This study aimed to quantify the prevalence of corresponding INTERPOL coded dental identifiers in cone beam computed tomography (CBCT) scans and panoramic radiographs (PR). The sample consisted of 100 CBCT scans and 100 PR taken the same day from the same patients (35 males and 65 females). Randomly and independently, forty-one INTERPOL coded dental identifiers were searched in each image. Wilcoxon test compared the prevalence of codes in CBCT scans and PR, Chi-square tested the dependence between codes and teeth; and multiple correspondence analyses (MCA) explored the association between codes and teeth in color maps for CBCT scans and PR. No statistically significant differences between the prevalence of identifiers in CBCT scans and PR were detected (p=0.693). In CBCT scans and PR, dependence between teeth and codes was detected (p<0.05). In the study sample, the strongest associations were found between the codes unerupted (UNE), partially erupted (ERU) and impacted (IMV) and third molars, both in CBCT scans and PR. INTERPOL coded dental identifiers registered on CBCT scans and PR can be exchanged during human identification.

Forensic thanatology and the pink tooth phenomenon: From the lack of relation with the cause of death to a potential evidence of cadaveric decomposition in dental autopsies - Case series

Forensic thanatology comprises the investigation of every phenomenon related to death performed through cadaveric exams. The pink tooth phenomenon (PTP) emerges as a thanatological finding registered during medical or dental autopsy. The PTP consists of a reddish or pink coloration caused in the teeth by the penetration of pulpal hemoglobin in the dentinal tubules. Initially, the PTP was associated with specific violent deaths, such as drowning, hanging and poisoning. However, scientific reports have pointed towards the occurrence of PTP as an expression of cadaveric decomposition regardless of the cause of death. The present study aims to report eight dental autopsies of victims of violent death that presented the PTP. The autopsies were conducted by forensic pathologists and dentists between 2013 and 2018. Seven victims were males and one was female. The age ranged above 6years old. Cranio-encephalic trauma, firearm shooting and asphyxia figured as the causes of death. All the victims were in advanced decomposition. The PTP was detected in deciduous and permanent, anterior and posterior and maxillary and mandibular teeth. Forensic experts, especially dentists, must be aware of the PTP for more detailed registration of postmortem findings and more accurate cadaveric exams.

Tooth reconstruction in forensic situations through dental materials: An anatomical art

Introduction:

Dental identification is a frequently applied method of forensic investigation, in mass disasters, accidents, and criminal investigations, where the human remains are decomposed, charred, or skeletonized. However, in such events, teeth may dislodge due to postmortem loss or mishandling during transporting and packaging which may further hamper with the identification of an individual.

Aim:

To investigate the potential for reconstruction of missing teeth utilizing dental materials.

Subjects and Methods:

Impressions of the intra-alveolar morphology of the empty sockets of a mandible were taken utilizing different impression materials. Positive replicas were prepared, and the profile of the missing/absent dental roots and crowns was constructed. Standardized radiographs were taken to assess the reliability of the method.

Results:

Based on the subjective observation, the combination of light body and heavy body (Putty)-addition silicone (for negative replica), self-cure (pink-colored) resin (for positive replica), and flowable composite resin (for reconstruction) gave the best outcome among the materials used.

Conclusion:

Tooth reconstruction utilizing dental materials that may help in comparative identification.

Forensic Identification of Decomposed Human Body through Comparison between Ante-Mortem and Post-Mortem CT Images of Frontal Sinuses: Case Report

Objective

The aim of this paper is to report on a case of positive human identification of a decomposed body after the comparison of ante-mortem (AM) and port-mortem (PM) computed tomography images of frontal sinus.

Case report

An unknown, highly decomposed human body, aged between 30 and 40 years, was found in a forest region in Brazil. The dental autopsy revealed several teeth missing AM and the presence of removable partial prostheses. The search for AM data resulted in a sequence of 20 axial images of the paranasal sinuses obtained by Multislice Computed Tomography (MSCT). PM reproduction of the MSCT images was performed in order to enable a comparative identification. After a direct confrontation between AM/PM MSCT, the data were collected for morphological findings, specifically for the lateral expansion of the left lobe, the anteroposterior dimension, and the position of median and accessory septa of the sinuses.

Conclusion

The importance of storing and interpreting radiographic medical data properly is highlighted in this text, thus pointing out the importance of application of forensic radiology in the field of law.

Three-dimensional analysis of the uniqueness of the anterior dentition in orthodontically treated patients and twins

Dental uniqueness can be proven if no perfect match in pair-wise morphological comparisons of human dentitions is detected. Establishing these comparisons in a worldwide random population is practically unfeasible due to the need for a large and representative sample size. Sample stratification is an option to reduce sample size. The present study investigated the uniqueness of the human dentition in randomly selected subjects (Group 1), orthodontically treated patients (Group 2), twins (Group 3), and orthodontically treated twins (Group 4) in comparison with a threshold control sample of identical dentitions (Group 5). The samples consisted of digital cast files (DCF) obtained through extraoral 3D scanning. A total of 2.013 pair-wise morphological comparisons were performed (Group 1 n=110, Group 2 n=1.711, Group 3 n=172, Group 4 n=10, Group 5 n=10) with Geomagic Studio^® (3D Systems^®, Rock Hill, SC, USA) software package. Comparisons within groups were performed quantifying the morphological differences between DCF in Euclidean distances. Comparisons between groups were established applying One-way ANOVA. To ensure fair comparisons a post-hoc Power Analysis was performed. ROC analysis was applied to distinguish unique from non-unique dentures. Identical DCF were not detected within the experimental groups (from 1 to 4). The most similar DCF had Euclidian distance of 5.19mm in Group 1, 2.06mm in Group 2, 2.03mm in Group 3, and 1.88mm in Group 4. Groups 2 and 3 were statistically different from Group 5 (p<0.05). Statistically significant difference between Group 4 and 5 revealed to be possible including more pair-wise comparisons in both groups. The ROC analysis revealed sensitivity rate of 80% and specificity between 66.7% and 81.6%. Evidence to sustain the uniqueness of the human dentition in random and stratified populations was observed in the present study. Further studies testing the influence of the quantity of tooth material on morphological difference between dentitions and its impact on uniqueness remain necessary.

Three-dimensional validation of the impact of the quantity of teeth or tooth parts on the morphological difference between twin dentitions

BACKGROUND

The number of teeth involved in cases of bite-mark analysis is generally fewer in comparison to the number of teeth available for cases of dental identification. This decreases the amount of information available and can hamper the distinction between bite suspects. The opposite is true in cases of dental identification and the assumption is that more teeth contribute to a higher degree of specificity and the possibility of identification in these cases. Despite being broadly accepted in forensic dentistry, this hypothesis has never been scientifically tested.

OBJECTIVE

The present study aims to assess the impact of the quantity of teeth or tooth parts on morphological differences in twin dentitions.

MATERIAL AND METHODS

A sample of 344 dental casts collected from 86 pairs of twins was used. The dental casts were digitized using an automated motion device (XCAD 3D® (XCADCAM Technology®, São Paulo, SP, Brazil) and were imported as three-dimensional dental model images (3D-DMI) in Geomagic Studio® (3D Systems®, Rock Hill, SC, USA) software package. Sub samples were established based on the quantity of teeth and tooth parts studied. Pair wise morphological comparisons between the corresponding twin siblings were established and quantified.

RESULTS

Increasing the quantity of teeth and tooth parts resulted in an increase of morphological difference between twin dentitions. More evident differences were observed comparing anterior vs. entire dentitions (p < 0.05) and complete vs. partial anterior dentitions (p < 0.05).

CONCLUSION

Dental identifications and bite-mark analysis must include all the possibly related dental information to reach optimal comparison outcomes.

Imaging for homicide investigations

The authors present the opportunities of the application of post-mortem imaging, focusing on post-mortem computed tomography and post-mortem computed tomography angiography in modern forensic investigation of homicide cases. The paper is based on scientific publications related to the subject from ca. the past 10 years, supplemented by the authors' own experiences. The article is illustrated with reconstructions based on the authors' own cases related to homicide due to ballistic/sharp/blunt trauma. As is shown, the results of evaluation of post-mortem computed tomography allow better diagnosis, documentation and visualisation of forensic examinations.

The uniqueness of the human dentition as forensic evidence: a systematic review on the technological methodology

The uniqueness of human dentition is routinely approached as identification evidence in forensic odontology. Specifically in bitemark and human identification cases, positive identifications are obtained under the hypothesis that two individuals do not have the same dental features. The present study compiles methodological information from articles on the uniqueness of human dentition to support investigations into the mentioned hypothesis. In April 2014, three electronic library databases (SciELO®, MEDLINE®/PubMed®, and LILACS®) were systematically searched. In parallel, reference lists of relevant studies were also screened. From the obtained articles (n = 1235), 13 full-text articles were considered eligible. They were examined according to the studied parameters: the sample size, the number of examined teeth, the registration technique for data collection, the methods for data analysis, and the study outcomes. Six combinations of studied data were detected: (1) dental shape, size, angulation, and position (n = 1); (2) dental shape, size, and angulation (n = 4); (3) dental shape and size (n = 5); (4) dental angulation and position (n = 2); (5) dental shape and angulation (n = 1); and (6) dental shape (n = 1). The sample size ranged between 10 and 1099 human dentitions. Ten articles examined the six anterior teeth, while three articles examined more teeth. Four articles exclusively addressed three-dimensional (3D) data registration, while six articles used two-dimensional (2D) imaging. In three articles, both imaging registrations were combined. Most articles (n = 9) explored the data using landmark placement. The other articles (n = 4) comprised digital comparison of superimposed dental contours. Although there were large methodological variations within the investigated articles, the uniqueness of human dentition remains unproved.

Evaluation of a personal identification method using the fusion function of CT images and dental radiographs

OBJECTIVES

We applied the fusion function of dental analysis software to examine whether the anatomical relationships of tooth roots when compared between reconstructed post-mortem CT (PMCT) and dental radiographs can aid dental identification.

METHODS

One PMCT image taken from a cadaver (43-year-old male; Cadaver 1) was compared with 64 digital dental radiographs of the left and right upper and lower molars from Cadaver 1 and 30 other cadavers. Five corresponding anatomical reference points were marked on each image. After adjusting the angle and magnification using the fusion function, the automatically calculated error in pixels was determined five times for each of four sites on the images.

RESULTS

Comparison of the PMCT image with the dental radiographs from the other cadavers revealed obvious discrepancies in the anatomical positioning of the teeth. When t-tests were applied to the data from any of the four sites, the error in pixels was found to be significantly smaller (p < 0.001) between Cadaver 1 and the other cadaver images. The average error in pixels between the PMCT and dental radiographs was smaller in the lower jaw than in the upper jaw.

CONCLUSIONS

This method uses corresponding reference points on two images to calculate the error between the regions that contain all points. This feature also makes it possible to compare images taken with different modalities. The demand for a dental identification method involving PMCT is likely to increase, and we expect that the accuracy of dental identification will improve by using radiological images.

Dental Identification Through Endodontic Radiographic Records: a Case Report

OBJECTIVE OF WORK

The present study aims to report a case of successful human identification based on the comparison of ante-mortem and post-mortem records of endodontic treatment. Based on these, the legal value of storing and updating clinical records is highlighted throughout the text.

CASE REPORT

An unknown body was recovered from a traffic accident site. Forensic examination was conducted in order to establish the identity of the victim. Based on the absence of ante-mortem fingerprint registration in the national database, the search for AM data was performed using periapical radiographic records from private dental clinics. A positive dental identification was achieved analyzing evidence of endodontic treatment.

CONCLUSION

Dental radiographs play a valuable role as legal tools supporting the criminal demands on the daily forensic practice. Specifically in endodontics, periapical radiographs are essential for a proper treatment. In forensics, these radiographs represent a solid source of ante-mortem data for human identifications.

Improving traditional dental autopsies in postmortem examinations of intraoral gunshot wounds

Despite the recent advances in the post-mortem forensic examinations, some medico-legal institutes are limited in accessing improved technological facilities, hampering an optimal autopsy. Specifically in developing countries, high-cost imaging devices are not afforded, making necessary the development of alternative autopsy techniques. In parallel, in dental autopsies muscle stiffness is often observed lacking mouth opening. This situation is specifically worse in cases of intraoral firearm injuries, in which detailed description of the detected wounds must be reported post-mortem. Based on this context, the present study aims to illustrate two cases of intraoral firearm injuries, in which the dental autopsies were performed considering a conservative and alternative technique for the improvement of mouth opening. Both cases provided optimal results, indicating the new approach as a valuable tool for dental autopsies.