Quantifying the potential of morphological parameters for human dental identification: part 1-proof of concept.

In forensic identification, lack of eccentric characteristics of intact dentitions hinders correct ante-mortem/post-mortem (AM/PM) matching. It remains unclear which morphological dental parameters hold strong potential as identifiers. This study aimed to establish a method to quantify and rank the identifying potential of one (or a combination of) continuous morphological parameter(s), and to provide a proof of concept. First, a statistic was defined that quantifies the identifying potential: the mean potential set (MPS). The MPS is derived from inter-observer agreement data and it indicates the percentage of subjects in the AM reference dataset who at least need to be considered to detect the correct PM subject. This was calculated in a univariate and a multivariate setting. Second, the method was validated on maxillary first molar crowns of 82 3D-digitally scanned cast models. Standardized measurements were registered using 3D modeling software (3-Matic Medical 12.0, Materialise N.V., Leuven, Belgium): tooth depth, angles between cusps, distances between cusps, distances between the cusps, and the mesial pit. A random sample of 40 first molars was measured by a second examiner. Quantifying and ranking the parameters allowed selecting those with the strongest identifying potential. This was found for the tooth depth (1 measurement, MPS = 17.1%, ICC = 0.879) in the univariate setting, and the angles between cusps (4 measurements, MPS = 3.9%) in the multivariate setting. As expected, the multivariate approach held significantly stronger identifying potential, but more measurements were needed (i.e., more time-consuming). Our method allows quantifying and ranking the potential of dental morphological parameters as identifiers using a clear-cut statistic.

[Automated digital superimposition of the 3D model and archival photographs of full removable dentures in forensic dentistry]. / Avtomatizirovannoe tsifrovoe issledovanie v sudebno-stomatologicheskoi ekspertize dlya sopostavleniya ob"emnoi modeli i arkhivnykh fotografii polnykh s"emnykh protezov.

THE AIM THE STUDY: The purpose of the work is to perform automated alignment of two-dimensional archival photographs of the first prosthesis and a digital model of the complete removable prosthesis by superposition in order to determine or deny their possible belonging to one user. MATERIALS END METHODS: The superposition was carried out in the Exocad program (DentalCAD 3.0 Galway) using the standard 2D-3D alignment algorithm of the «SmileDesign¼ module; in the same program. In addition, Keynote and Fusion 360, and Autodesk programs were used. Statistical measurements were carried out at the statistically significant level of p<0.05. RESULTS: A comparison of four different-angle and different-scale photographic images of a removable denture of the upper jaw teeth with a three-dimensional copy of the same version of the prosthesis of the life physician of the royal family E.S. Botkin was made. When superimposing a digital three-dimensional model and a two-dimensional photograph of the original prosthesis with marked anthropometric points (n=51), 21 of them coincided or touched each other (41.2%). Another 26 points were located side by side (distance up to 1.5 mm) (50.9%) and 4 did not coincide (distance >1.5 mm, but no more than 3.5-4 mm) (7.8%). When the reference points were combined, the contours, the configuration of the relief and the peripheral boundaries of all three objects mostly coincided. The linear longitudinal and transverse dimensions of the bases of the prostheses also mostly coincided. The exception was the distal border of the bases, and the level of the cutting edges of the anterior artificial teeth, where complete coincidence was not observed, due to differences in the degree of erasability. CONCLUSION: Comparison of the original prosthesis from Ipatiev's house and its stereolithographic model was a test for the accuracy of the matching method used. The stereotype of the compared images is proved and the consistency of the possibility of computer combination of three-dimensional and two-dimensional objects is confirmed. The use of traditional methods of forensic identification and evaluation of the results by methods of mathematical statistics allowed us to conclude that the two different complete removable dentures of the upper jaw depicted in the photographs belong to one user.

Survey of dental hygienists' and dental hygienist students' attitudes towards body identification tasks of unidentified human remains.

OBJECTIVE: Dental findings are used to identify unidentified human remains. The post-mortem records, necessary for the appraisal of dental findings, are created by the dentist; however, a system for dental hygienists specializing in these tasks to utilize has not yet been considered. METHODS: This study was directed at both students at a dental hygienist school and dental hygienists. We conducted an awareness survey on their willingness to participate in these tasks, as well as the need for education regarding body identification tasks. RESULTS: The results showed that students and dental hygienists are highly interested in body identification tasks and highly motivated to participate. Numerous participants preferred to take courses regarding basic knowledge in both lecture and practical training settings to acquire the knowledge necessary for performing these tasks. CONCLUSIONS: It is necessary to consider the curriculum content and timing of lectures and practices related to body identification tasks. Participation limited to the creation of post-mortem records, except for the creation of antemortem records requiring diagnosis and treatment knowledge and the matching task of antemortem records and post-mortem records, should be considered to prevent the tasks of dental hygienists from excessively expanding. If dental hygienists train properly, intraoral findings records can be drawn up by a team consisting of 1 dentist and 1 dental hygienist. Therefore, it is expected that the use of forensic dental identification, which is a relatively quick identification method, will be further improved.

Personal Identification by Superimposition of Three-dimensional Intraoral Models.

Victim identification following disasters is an important task for the dentist. Use of records of previous dental treatment proved effective in victim identification after the crash of Japan Airlines Flight 123 in 1985. This dental identification procedure can be problematic, however. In exceptional cases, the victim may have had very little or no prior treatment, making identification by this means impossible. The purpose of this study was to establish a new method of dental identification based on morphological comparison of the oral cavity, rather than on evidence of prior dental treatment. This new method involves superimposing 3-dimensional (3-D) models created by digital impression-taking devices, use of which is becoming increasingly widespread in present-day dental treatment. A total of 75 dental models were used to obtain 3-D models. These were then used in a total of 77 superimposition tests. The results demonstrated that the degree of similarity was 98.03－41.30%, and the degree of difference 0.17－29.69%. This indicated that differences among the dental models could be identified with 100% precision. Personal identification by superimposition of such 3-D models offers a useful tool that could compensate for the shortcomings of standard dental identification.

Differentiation of dental restorative materials combining energy-dispersive X-ray fluorescence spectroscopy and post-mortem CT.

Today, post-mortem computed tomography (CT) is routinely used for forensic identification. Mobile energy-dispersive X-ray fluorescence (EDXRF) spectroscopy of a dentition is a method of identification that has the potential to be easier and cheaper than CT, although it cannot be used with every dentition. In challenging cases, combining both techniques could facilitate the process of identification and prove to be advantageous over chemical analyses. Nine dental restorative material brands were analyzed using EDXRF spectroscopy. Their differentiability was assessed by comparing each material's x-ray fluorescence spectrum and then comparing the spectra to previous research investigating differentiability in CT. To verify EDXRF's precision and accuracy, select dental specimens underwent comparative electron beam excited x-ray spectroscopy (EDS) scans, while the impact of the restorative surface area was studied by scanning a row of dental specimens with varying restorative surface areas (n = 10). EDXRF was able to differentiate all 36 possible pairs of dental filling materials; however, dual-energy CT was only able to differentiate 33 out of 36. The EDS scans showed correlating x-ray fluorescence peaks on the x-ray spectra compared to our EDXRF. In addition, the surface area showed no influence on the differentiability of the dental filling materials. EDXRF has the potential to facilitate corpse identification by differentiating and comparing restorative materials, providing more information compared to post-mortem CT alone. Despite not being able to explicitly identify a brand without a control sample or database, its fast and mobile use could accelerate daily routines or mass victim identification processes. To achieve this goal, further development of EDXRF scanners for this application and further studies evaluating the method within a specific routine need to be performed.

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.

Human identification using dental techniques: A case report.

Dental identification of skeletal remains frequently relies on data comparison. Comparative dental identification is used to establish with a high degree of certainty that the remains of a corpse and a person represented by ante-mortem dental records are the same individual. There is no minimum number of concordant points necessary to perform a positive identification; rather, each case is unique and should be treated as such. In this paper, we present a report of a case in which positive identification was made by a paramolar tubercle in both upper first deciduous molars.

[Old and new ways of personal and victim identification by dental methods. Review of the literature]. / A fogászati személy- és áldozatazonosítás régi és új módszerei. Irodalmi áttekintés.

The aim of this paper was to create a comprehensive literature review on forensic dental methods. This literature review is based on historical and the latest results of the forensic odontology. Thus, this comparative study deals with various methods including certain dental identification methods which are easy to use and do not require advanced technological background. Nowadays, the main reasons for the use of forensic odontology methods are natural disasters, however, their sensitivity depends on the availability of proper dental documentation of the subject/victim. Custom made prostheses offer the most accurate dental identification, which can allow an identification rate of 99.9%. Combination of different methods can also exhibit a high sensitivity (40-99.9%). It seems important that separation of old and novel methods is not recommended. Also, it is important to maintain and upgrade present methods which are capable of identifying one or more subjects/victims in practice. The authors propose several methods which could serve as a base of the new national policy in forensic dental identification and could be used by teams dealing with the identification of disaster victims.

Dental Identification System in Public Health: Innovations and Ethical Challenges: A Narrative Review.

Dental identification systems (DISs) encompass various techniques used for forensic identification, serving as alternatives or complements to genetic methods. Technologies such as microchip implants, prosthetic inscriptions, microSD cards, and identification plaques have been proposed to address limitations in comparative methods, offering streamlined processes for forensic experts. This study reviews current and potential DIS implementations, emphasizing cost-effectiveness and community benefits. Literature analysis from PubMed (2008-2024) yielded 17 relevant articles on implantable DISs, enabling direct subject identification via teeth or prostheses. The integration of DIS aims to enhance accuracy and speed in personal profiling and legal identification, promoting technology transfer in dentistry. It will be necessary to develop strict privacy regulations to protect patient data and establish ethical guidelines for their use. The study's aim is to highlight that the universal adoption of DISs could mitigate healthcare disputes and facilitate data exchange in clinical settings, which is particularly beneficial for vulnerable populations.

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.

Civil aircraft accident investigation.

This talk reviews some historic aircraft accidents and some more recent. It reflects on the division of accident causes, considering mechanical failures and aircrew failures, and on aircrew training. Investigation results may lead to improved aircraft design, and to appropriate crew training.

Dental implants and forensic identification: A systematic review.

The use of dental implants has witnessed great popularity in recent years. It has been documented that dental implants are valuable aids in forensic identification. In particular, in the event of mass disasters, where distortion of body features may render the process of forensic identification challenging. The present review aims to explore the application of the use of dental implants in forensic identification. A literature search was performed on PubMed and Web of Science electronic databases. All studies addressing the application of dental implants for forensic identification published in English were eligible for inclusion in the review. This systematic review included a total of 14 articles that demonstrated the significance of dental implants in forensic identification. Three studies reported the use of dental implants in the process of identification of the deceased, one of which found the distance of the implant from the maxillary sinus was a pathognomonic feature of identity. Four studies conducted incineration experiments to assess dental implant characteristics following incineration. The studies identified the batch number and characteristic threads and grooves on dental implants despite incineration. The remaining studies evaluated the role of radiological assessment in identification. The findings of the aforementioned studies highlighted the benefits of radiologic imaging in identification. Dental implants carry extreme significance in forensic identification owing to their durability and ability to withstand extreme temperatures. This process can be further enhanced by the implementation of advanced technology in forensic cases.

Forensic odontology in DVI-A path forward.

Dental identification is a pillar of disaster victim identification (DVI). Dental identification is accurate, efficient, inexpensive, and accepted in courts of law. The (known) antemortem (AM) dental charts and radiographic images acquired from the dentist of the missing person are evaluated, processed, and compared to post mortem (PM) findings present in the dentition or fragments of the dentition of the deceased individual. These comparisons evaluate and assess individuating restorative dental work, dental anatomical areas of concordance, spatial relationships of teeth one to another, and occasionally calculate the degree of "uniqueness" of either or both of the AM and PM dentition compared to known population databases. In a multiple fatality incident, odontologists may utilize age stratification to assist other means of identification. Computer comparison algorithms using recorded data can indicate possible matches between AM and PM data sets. Following clinical assessment, collection of post mortem tooth specimens for DNA profiling generation may be undertaken. This paper will highlight modern and efficient use of these tools. The framework for how dental identification in these incidents is currently managed is presented. The authors propose a change to this approach that moves away from interpretive subjective assessment toward comparisons based largely on objective data. The aim of this paper is to highlight the benefits of minimizing subjective decisions and maximizing objective data in the dental DVI process while simultaneously reducing risk to clinical personnel and minimizing costs by reducing the number of clinicians required onsite.

Operation makalu air crash: influence of cognitive and human factors on decision-making.

Two onboard crew members lost their lives in the fatal Makalu Air Cessna Grand Caravan 208B domestic cargo flight crash on May 16, 2018. The Disaster Victim Identification (DVI) procedure comprises external examination, photography, DNA collection, fingerprint collection, postmortem examination, antemortem information collection from the family members, and reconciliation. The major challenge of this operation was dealing with cognitive bias. The antemortem dental information of one of the deceased was revealed to the forensic experts just before the postmortem examination. This influenced the testing strategies. There was a tendency to neglect the complete dental examination presuming the identification was established. Later, during a thorough examination, the forensic odontologist realised that the initial decision was erroneous. Furthermore, there are few experience-based resources available to resolve cognitive bias issues. The authors begin by summarising complicated operations in which they have been involved, followed by a discussion of the key sources of cognitive bias along with the solution to resolve these issues in DVI preparedness planning.

Analysis on unidentified cases in which dental information was collected from 2014 to 2019 in Miyagi Prefecture, Japan.

This study aimed to summarize the characteristics of unidentified cases in which dental information was collected during 2014-2019 in Miyagi Prefecture and to discuss the challenges and social characteristics of dental identification in routine forensic work. Cases were selected and examined from the database of dental charts collected at Tohoku University and the database of the Miyagi Prefectural Police. The annual percentage of cases with matched dental findings ranged from 19.2 - 37.1%, and 80.6% of the cases were identified within four days using dental information. The most common age group was the 50-70 s. Males were more common in the 20-70 s, whereas females were more frequent in the 80-90 s age group. Utilization of dental information was lower for cases involving young people and those over 90 years of age. The number of unidentified cases and unspecified death cases in the central block was significantly higher than other regions. However, there were no significant differences in sex, age, and season between each region. Spearman's rank-order analysis of the unspecified deaths showed a strong correlation with the monthly average temperature (ρ = 0.89, p < 0.01). Within the limitations of this study, the results provide valuable information on the long-term progress of routine dental identification work and could be useful as a reference for a statistical survey. Future research must examine the role of dental information in forensic identification by exploring the role of more specific background characteristics among autopsy cases.

Roles of Dental Care in Disaster Medicine in Japan.

Purpose of Review: Natural disasters occur frequently in Japan. A disaster medical system was rapidly developed in Japan following the Great Hanshin-Awaji Earthquake in 1995. Dentistry has become increasingly important in disaster medicine. This review summarizes the roles of dental professionals in disaster medicine, highlights relevant issues, and identifies new directions for research to improve disaster relief activities based on our previous experiences as dental professionals supporting the victims of major disasters. Recent Findings: Many preventable deaths after a disaster are caused by aspiration pneumonia, which occurs against a background of factors that are compounded by a harsh living environment. An important aim of dental care in disaster medicine is to prevent these disaster-related deaths in vulnerable persons such as the elderly. This can be achieved through interventions to maintain oral hygiene, preserve and enhance oral function (i.e., chewing and swallowing), and improve the diet, since these interventions help to prevent the development of malnutrition and frailty in vulnerable people. Dental identification of disaster victims could be improved through the use of intraoral three-dimensional scanners and artificial intelligence to automate the acquisition of dental findings and through the construction of a national database of digitized dental records. Advances in personal identification methods will be needed given the prediction that a catastrophic earthquake will occur on the Nankai Trough during the next 30 years and claim more victims than the 2011 Great East Japan Earthquake. Summary: Disaster-related deaths due to aspiration pneumonia can be prevented by providing appropriate dental care to those in need. The process of identifying victims could be made more efficient through the use of intraoral three-dimensional scanning, artificial intelligence, and a digital database of dental records. Establishing and strengthening relationships between professionals in different regions will help to optimize the multidisciplinary response to future large-scale disasters.

Effect of cranium structure on dose distribution during intraoral radiography.

OBJECTIVES: This study aimed to evaluate, the effect of the cranium structure on dose distribution by measuring the dose using the RANDO phantom for safe use of an X-ray unit during personal identification work at a large-scale disaster site. METHODS: As the subject, the head and neck of the RANDO Phantom (Alderson) containing a dry skull composed of a tissue-equivalent substance and having a shape similar to that of a living body were studied. With the body in the supine position, the air doses per second of irradiation time were measured for a total of six sections of the anterior, premolar, and molar teeth (molar on the left side) at a tube voltage of 60 kV and tube current of 10 mA during maxilla and mandible intraoral radiography. RESULTS: The region having the highest exposure dose was the main X-ray direction in both the mandible and maxilla. Conversely, the dose tended to be low in the range from the temporal region to the occipital region on both sides of the horizontal plane, from the frontal region to the occipital region of the sagittal plane, and in the parietal region of the frontal plane. CONCLUSIONS: It would be preferable to examine from the top of the body where the dose tends to decrease for all imaging sites.

Application of 3D imaging and selfies in forensic dental identification.

With increased access to smartphones, the selfie has gained immense popularity in the past decade. Selfie images could be a significant source of ante-mortem (AM) image data in cases where dental records are unavailable or considered insufficient. The application of 3D imaging and selfies has not been explored to its full potential in human dental identification. The present study aimed to evaluate the feasibility of using selfies as AM data and comparing with 3D post-mortem (PM) scans as an alternative to multiple 2D PM photographs in forensic dental identification. The study sample consisted of 18 selfies (12 matching and 6 non-matching) and 15 3D dental scans obtained from the study participants. The study sample was assessed by 6 experienced forensic odontologists (Raters) in two phases; Phase I-Visual comparison of 2D selfies to 3D scans and Phase II-2D selfies superimposed upon 3D scans. Each rater looked at 15 cases, and a total of 1620 comparisons were made by 6 raters (72 for the 12 matching cases and 1548 were for non-matching) and the opinions for each of the comparisons were analyzed. The results of the study show that use of the 3D superimposition method increased the certainty of the conclusions reached by the raters for the cases with correct matches. Furthermore, 94.2% of the 1548 non-matching comparisons were correctly excluded, compared with 77% for the 2D visual comparison method. The study demonstrated the applicability of this 3D method as a valuable tool in assisting the forensic odontologist with dental identification using selfies.

Forensic dental identification using two-dimensional photographs of a smile and three-dimensional dental models: A 2D-3D superimposition method.

Photographs of a person smiling may provide valuable information about their anterior dentition. These images can be an alternative ante-mortem (AM) dental source in cases with no dental records, which gives the forensic odontologist a significant opportunity for comparative dental analysis. There are no reported studies that have investigated the reliability of a superimposition technique using 2D photographs of a smile and 3D dental models in dental identification. The aim of this study was to explore novel odontological methods by combining 2D photographs with 3D dental models, simulating a dental identification scenario. The objective was to increase the accuracy of dental identification using an AM photograph with the aid of 3D imaging as an alternative to post-mortem (PM) photographs. The study comprised of 31 3D dental models (simulating PM information) and 35 digital photographs (simulating AM information). The data was analysed in two phases: Phase I- Visual Comparison of 2D-3D images and Phase II- 2D-3D superimposition after a wash out period. Both methods were analysed by the principal investigator. Further, one-third (ten) of the sample was evaluated by six raters (three experienced forensic odontologists and three forensic odontology MSc. students). The inter-rater agreement was assessed using intra-class correlation (ICC 2, 1, absolute). The results of the study suggest that the inter-rater and intra-rater reliability using 3D superimposition was highest (ICC ≈ 1.0). In summary, there was an increase in match rates and higher certainty among the opinions reached when using the 2D-3D superimposition method. The procedure attempted to reduce the limitations of previously existing 2D methods and is intended to assist forensic experts with an alternative method in dental identification when expressing conclusions on a case using photographs.

Reduction of operator exposure by rectangular collimation in portable intraoral radiography.

Portable intraoral X-ray units are frequently used for home-visit dental treatment and personal dental identification. Therefore, the reduction of operator exposure is crucial. Rectangular collimation is effective at reducing patient exposure and operator exposure; however, its effects are not known. We investigated the reduction of operator exposure through rectangular collimation by measuring the backscattered dose in relation to the operator exposure dose. Using a portable intraoral X-ray unit, a head phantom for CT dose measurement as the object, a dosimeter, and stainless-steel rectangular collimator, a 1-cm ambient dose equivalent was measured in intervals of 15° in horizontal and vertical planes with the radii of 50 and 100 cm. The backscattered dose decreased to approximately one-third when a rectangular collimator was attached to the cone tip. This may have been due to the reduction of the volume of scattered X-rays generated in the phantom by rectangular collimation. We clarified that rectangular collimation is effective at reducing the operator exposure and is useful for protecting the operators of portable intraoral X-ray units during home-visit dental treatment and personal dental identification.