The Role of Forensic Odontology in the Field of Human Identification

The profession of forensic odontology can make a significant contribution to the field of forensic science in the identification of people both dead and living. The opinion of this author is that this profession is often neglected. This article is a non-technical review of the basic methods that can be used to gather scientific evidence through the use of forensic odontology. Because of the uniqueness of bite patterns, bite marks can identify a person with enough accuracy to result in conviction by the courts. In cases where an unidentified body is skeletonized or visual identification or fingerprint identification is not possible, identification can be established by dental identification. In cases of mass disaster such as airplane crashes or fires, dental identification can be the most useful method not only of determining identity but also of determining the number of victims involved in the disaster. Dental examination can establish characteristics unique to an individual which can be useful as aids in establishing identity. There are several significant obstacles to overcome including lack of standardization and computerization before dental identification can be better utilized. Neglect by the dental profession and dental colleges of this contribution to science should be addressed.

[EDITOR'S NOTE: Dr. Kim is currently Chairman of the Department of Biomedical Dental Sciences, College of Dentistry, King Saud University in Saudi Arabia. Dr. Kim has also served as the Associate Editor on Forensic Dentistry for this journal for the past five years.—Editor.]     

Methods for identification of 28 burn victims following a 1996 bus accident in Spain

A car collided head-on with a bus containing 56 passengers plus the driver. A few seconds after the crash, the bus caught fire and 28 persons (15 male and 13 female) lost their lives. All the deceased were almost completely incinerated. To establish the identity of the victims, the judge in charge of the case designated a multidisciplinary Identification Commission. Postmortem procedures included a general external examination, routine photographs, dental examination, dental (intraoral and extraoral) and general radiographs (chest, ankle, etc.), and complementary biological methods for identification (e.g., DNA analysis). The antemortem information, including dental and medical records available, were transcribed onto the INTERPOL disaster victim identification forms. The detailed ante- and postmortem information were compared manually. In this disaster dental identity could be established in 57% of the victims, whereas dental evidence did not allow by itself the identification of 12 burned victims. Odontological examination and complementary radiographic procedures were found to be accurate, economic and rapid methods of identifying badly burned victims in this bus accident.     

Associated postmortem dental findings as an aid to personal identification.

The use of the unique features of the human dentition to aid in personal identification is well accepted within the forensic field. Indeed, despite advances in DNA and other identification methodologies, comparative dental identifications still play a major role in identifying the victims of violence, disaster or other misfortune. The classic comparative dental identification employs the use of postmortem and antemortem dental records (principally written notes and radiographs) to determine similarities and exclude discrepancies. In many cases the tentative identification of the individual is unknown and therefore antemortem records cannot be located. In such a situation a dental profile of the individual is developed to aid the search for the individual's identity. With such a profile a forensic odontologist can identify and report indicators for age at time of death, race (within the four major ethnic groups) and sex. In addition to these parameters the forensic dentist may be able to give more insight into the individual. This paper outlines, for the non-expert, some of the additional personal information that can be derived from the teeth of the deceased, and which may assist in their ultimate identification.     

A new system for computer aided dental identification in mass disasters

In recent years, several computer programs for dental identification in mass disasters have been developed. Unfortunately, it may be difficult to get access to such programs. The Norwegian police presently utilizes a text retrieval program, NOVA¹STATUS, for detection work. This program is based on the British STATUS ONE program, and it enables the user to find from a large pool of postmortem dental registration one or several sets containing specific information about one tooth or several teeth. The complete relevant set(s) can be displayed for visual examination and comparison. A coding system for dental information has been developed as well as a system for interrogating the computer. This system and its efficiency have been tested on a simulated small scale disaster where various well-known difficulties in dental identification were included.     

西安“六.六”空难的法医学鉴定

本文报告了１９９４年６月６日，中国西北民航Ｂ—２１６０号客机在西安失事的法医学鉴定。机上乘员１６０人全部遇难、死难中，以撞击伤为主，主要死因为多脏器严重损伤、创伤休克、大出血。１６０名遇难者中，１３９人经体貌特征和遗物被确认，６例通过血型被认定，３例通过指纹被认定，其余通过牙齿被确认。本文还讨论了如死亡时间等空难中的法医学处理问题。     

Major incident response: collecting ante-mortem data

The Asian tsunami of 26 December 2004, which devastated coastal parts of more than 10 countries in and around the Indian Ocean caused over 200,000 casualties. People from more than 58 nationalities were amongst the victims and subsequently an international effort for disaster victim identification (DVI) was set up, coordinated by Interpol. DVI teams from more than 20 countries took part in the identification process which, because of the complexity of the situation, had to be conducted in an internationally agreed upon procedure. Standard operating protocols of post-mortem (PM) procedures were established for fingerprinting, forensic pathology, forensic odontology and DNA profiling and were crucial in the quality of the entire DVI process of the quickly decomposing bodies. A very important and underestimated part of the DVI process is the gathering of the ante-mortem (AM) data of the persons reported missing in their home countries. In the wake of this tsunami event it appeared to be even more problematic as entire families had died and information was difficult to obtain. As dentistry proved to be the most valuable identification mean--up to 85% of the cases--the AM dental records proved to be crucial elements for DVI. Standard operating protocols (SOP) were again established as to who, where, when and what information had to be collected by the dentists by the AM teams abroad. Transcribing the AM dental information by experienced forensic odontologists was another crucial element in the whole identification procedure as the information had to be loaded into the DVI System International (Plass Data, Holbaek, Denmark) for comparison with incoming PM data. The Interpol DVI Standing Committee thus recommends that forward planning, adequate funding, international cooperation and standardisation are essential to guarantee an effective response to any major mass disaster of this kind in the future.     

Dental identification using digital images via computer network

Dental identification is a useful scientific method. In Japan, however, there are only a few forensic odontologists; moreover, until now, forensic dental services have only been offered by general dentists. These dentists may not be able to offer such forensic services during office time. For a quick comparison, the authors tried sending digital photos, taken with a 2-million-pixel digital camera, to dental offices via the Internet. If a dental office has Internet access, it is possible for dental charting to be sent directly to the autopsy room. Of course, digital images only provide the first outline. However, when antemortem dental records of the person in question are available at autopsy, a quick comparison can be made.     

The design and assessment of mock mass disasters for dental personnel

Mass disasters represent a significant challenge for dental personnel who are frequently called upon to provide identifications. Recently-published materials have highlighted the need to prepare such groups for the disaster challenge and to report inadequacies in existing preparation methods with an emphasis on team integration, organization, and the psychological and emotional effects of such work. Many studies have retrospectively reported errors that have been made in disaster situations, but few have addressed the issues proactively. In an effort to provide a prepared team of dental members, a mock disaster exercise (Operation: DENT-ID) is conducted annually in Vancouver, Canada. The present study analyzes the effectiveness of this exercise in relation to team organization, assessment of preparedness, and the emotional and psychological issues. An index of preparedness is developed and described. This index, in the form of a questionnaire, can be given to participants in mock disasters to assess the effectiveness of such exercises. While the focus of this paper is on the assessment of dental personnel, the indices and methods used can be applied to any group working within the disaster team. Results indicate that the increase in preparedness as a result of the exercise was highly significant.     

“Identified”, “probable”, “possible” or “exclude”: The influence of task-irrelevant information on forensic odontology identification opinion

In a mass disaster situation, identification of the deceased utilising comparison of dental features is frequently heavily relied upon to facilitate rapid and accurate outcomes. The method consists of the comparison of clinical and radiographic records depicting oral structures and dentition to allow an opinion to be produced on a presumed identity. Current forensic odontology identification opinions are expressed as categories of levels of identification. Categories such as “Identified”, “Probable”, “Possible” and “Exclude” are used in various forensic odontology identification scales. The boundaries between the levels of the scales are not fixed; hence, category selection is highly subjective. It is uncertain how extrinsic factors such as exposure to contextual task-irrelevant information or operator experience influence category selection. In this study, forensic odontologist and dentist participants read task-irrelevant context case information containing either strong or weak identification or non-identification suggestions before evaluating and comparing pairs of true matching and non-matching dental radiographs. They were then asked to form an opinion regarding identification using one of four categories from the INTERPOL scale. Context information was found to influence categorical decisions. The magnitude and direction of influence depended on the type of participant, the true match status of the radiographs, and the strength and direction of bias of the context. The results of this study demonstrate the contextual effect and fluidity of the boundaries between the categories on the identification scale and highlight the need for stringent protocols to be developed regarding the use of these categorical scales to enable decision making to be more objective.     

Dental participants in mass disasters--a retrospective study with future implications

Mass casualty incidents continue to require the services of forensic dentists to determine the identity of victims. Across North America and Europe. teams of forensic dentists train, using mock disaster exercises, to prepare for such duties. It is vital that these mock exercises simulate the features of real disaster situations as far as possible. In order to inform those responsible for the design and implementation of mock exercises, a study was undertaken to determine the features of actual disasters that dental personnel had attended. Using a questionnaire, data were solicited from 38 odontologists. The average number of disasters attended by the respondents was eight, with an average casualty number of 94. Aircraft crashes were the most frequent cause of disasters that were attended by the odontologists. The authors conclude that future mock disaster exercises should replicate features of aircraft crashes as closely as possible by using commingled, fragmented, and burned remains. In addition, mock disasters should require the identification of a realistic number of individuals to ensure authenticity and the maximum logistical preparedness of participants.     

Solving certain dental records problems with technology--the Canadian solution in the Thailand tsunami response

Each natural or man-made disaster presents a different set of circumstances and, as a consequence, each event results in new challenges for response teams. The very large number of deceased victims in recent tragic events is certainly one of the enormous challenges that can tax many different resources for identification specialists. But there are other significant challenges. And during the response, some of these seem insurmountable. They can be solved if we embrace technologies outside the customary disciplines. The Canadian identification effort following the December 2004 tsunami involved responders from several disciplines. Each discipline faced challenges in many different and special areas that were difficult and in some cases previously unseen. This paper presents examples of the ways the Canadian identification team used Internet technology to solve problems that were encountered when it became necessary to duplicate victims' dental, medical and personal records, and transport these records halfway around the world. Digital images of the records were saved at high resolution in multi-page PDF files. These images were made available to on-site personnel using an encrypted, password-secured website.     

Self-assessment of the forensic value of dental records.

One of the most important aspects of a person's dental record may well prove to be it's potential value should the forensic dental identification of their remains become necessary. The better the quality of the antemortem dental records, the easier and faster the identification of the remains will be. The forensic dentist must be able to select identifying features by decoding the deceased's antemortem dental records. A study was conducted on two groups of dentists who were asked to self-assess the forensic dental value of the dental records maintained in their own practices. The three most frequently recorded identifying dental features, other than caries and restorations, were the presence of diastemas, displaced or rotated teeth, and dental anomalies. Surveyed dentists imbedded identifying information into the removable prosthetic devices fabricated for their patients an average of only 64% of the time. Only 56% of the two groups combined felt that their dental chartings and written records would be extremely useful in dental identifications. It is concluded that the quality of antemortem dental records available for comparison to postmortem remains varies from inadequate to extremely useful. Practicing dentists can become valuable members of the dental identification process by developing and maintaining standards of record keeping which would be valuable in restoring their patients' identity.     

The efficiency of an X-ray screening system at a mass disaster

This is a study to determine the efficiency and efficacy of using an X-ray security screening system to locate both dental fragments and other foreign objects that might be commingled with fragmented remains in a mass disaster. A controlled study by the Pennsylvania Dental Identification Team (PADIT) revealed that a manual examination of simulated body bags containing commingled dental parts and foreign objects by a team of trained forensic odontologists was very effective in locating dental fragments and in finding foreign objects. Although this was effective, it was not efficient, because it was very time consuming. With the use of an X-ray security screening system, the time factor could be reduced. This study also revealed that even though this sophisticated equipment could reduce the time factor in locating commingled dental and foreign objects, a forensic odontologist should be utilized to be most effective.     

Intelligent dental identification system (IDIS) in forensic medicine

This study reports the design and development of the intelligent dental identification system (IDIS), including its efficiency and reliability. Five hundred patients were randomly selected from the Dental Department at Police General Hospital in Thailand to create a population of 3000 known subjects. From the original 500 patients, 100 were randomly selected to create a sample of 1000 unidentifiable subjects (400 subjects with completeness and possible alterations of dental information corresponding to natural occurrences and general dental treatments after the last clinical examination, such as missing teeth, dental caries, dental restorations, and dental prosthetics, 100 subjects with completeness and no alteration of dental information, 500 subjects with incompleteness and no alteration of dental information). Attempts were made to identify the unknown subjects utilizing IDIS. The use of IDIS advanced method resulted in consistent outstanding identification in the range of 82.61-100% with minimal error 0-1.19%. The results of this study indicate that IDIS can be used to support dental identification. It supports not only all types of dentitions: primary, mixed, and permanent but also for incomplete and altered dental information. IDIS is particularly useful in providing the huge quantity and redundancy of related documentation associated with forensic odontology. As a computerized system, IDIS can reduce the time required for identification and store dental digital images with many processing features. Furthermore, IDIS establishes enhancements of documental dental record with odontogram and identification codes, electrical dental record with dental database system, and identification methods and algorithms. IDIS was conceptualized based on the guidelines and standards of the American Board of Forensic Odontology (ABFO) and International Criminal Police Organization (INTERPOL).     

Establishing personal identification based on specific patterns of missing,filled, and unrestored teeth

The primary goal of this research is to examine the overall utility of nonradiographic dental records for the establishment of individual identifications. It was found that even without radiographic lines of comparison, charts and notes that accurately detail a missing individual's antemortem dental condition can be essential for establishing an identification. Based on an analysis of two large datasets, individual dental patterns were determined to be generally unique, or at least very uncommon. Through this type of empirical comparison, it is possible to establish a strong, quantifiable association with a missing individual. The results of this research indicate that a definitive number of points of concordance do not need to be established in dental identification cases. Each case must be assessed individually. The critical factor is to remove subjective judgment calls from dental comparisons. This research has proposed a new method of empirical comparison that allows forensic odontologists to derive objective frequency information regarding the occurrence of specific dental patterns in the general population. The method is similar to that used for mtDNA casework, and a computer program (OdontoSearch) has been developed to make the technique accessible. It was found that even a small number of common dental characteristics may produce a very rare dental pattern, a point that may be counterintuitive to many forensic odontologists.     

A new algorithm for use in computer identification

On 9 May 1987, a Soviet-made IL-62M Polish airliner, LOT Flight 5055, crashed, exploded, and burned, killing the crew and 183 passengers. A forensic science team from the Armed Forces Institute of Pathology, comprised of 6 dental officers, 3 forensic pathologists, and 3 medical photographers, worked in concert with the Polish forensic science team. The small number of antemortem records and the extreme fragmentation of the remains presented a new scenario for computer use. Typically, the Computer-Assisted Postmortem Identification (CAPMI) software is used to compare remains against an antemortem database. Results are listed by the number of tooth-to-tooth matches based on restorative or other characteristics or both. The Polish disaster confounded this approach to some degree, however, and suggested a reconsideration of the theory on which the sort is made, that is, that the cases with maximum number of matches to preexisting dental records would be the most likely identification (ID) match. A hypothesis was constructed that, if searches were accomplished for fragments with a minimum number of mismatches, the correct matches would appear higher in the rank order. Six antemortem records (that had all dental information) were sorted against one hundred and twelve postmortem fragmented records. The resulting report was reordered so that records were listed by minimum number of mismatches. There was significant improvement in rank placement for all of the records. Thus it was accepted that in the situation of highly fragmented remains a different sorting based on the number of mismatches is indicated. Programming changes to make this option available have been implemented in the new version of CAPMI.     

Dental CT imaging as a screening tool for dental profiling: advantages and limitations

The use of dental processing software for computed tomography (CT) data (Dentascan) is described on postmortem (pm) CT data for the purpose of pm identification. The software allows reconstructing reformatted images comparable to conventional panoramic dental radiographs by defining a curved reconstruction line along the teeth on oblique images. Three corpses that have been scanned within the virtopsy project were used to test the software for the purpose of dental identification. In every case, dental panoramic images could be reconstructed and compared to antemortem radiographs. The images showed the basic component of teeth (enamel, dentin, and pulp), the anatomic structure of the alveolar bone, missing or unerupted teeth as well as restorations of the teeth that could be used for identification. When streak artifacts due to metal-containing dental work reduced image quality, it was still necessary to perform pm conventional radiographs for comparison of the detailed shape of the restoration. Dental identification or a dental profiling seems to become possible in a noninvasive manner using the Dentascan software.     

Identification of a skeleton using DNA from teeth and a PAP smear.

Identification of unknown living or deceased persons using dental treatment records is an established forensic technique. However, some cases remain unidentified, especially when antemortem dental records are not available for comparison to postmortem dental records. Cytological smears have been previously reported to be potential sources of DNA reference samples which can be compared to DNA recovered from found human remains. The case described here involves an adult skeleton which exhibited extensive, complex dental restorative treatment. A putative identification of the found skeleton as a missing woman was established using circumstantial evidence found at the scene. However, it became important to establish a positive identification using reliable scientific methods. When it was discovered that antemortem dental records were not available because the treatment was completed in another country and the treating dentist could not be found, cytological smears stained with Papanicolaou (PAP) stain obtained from the putative decedent's medical records were used as a reference DNA sample. DNA was recovered from the teeth of the skeleton using cryogenic grinding. Comparison of the genotypes resulted in the conclusion that the DNA originated from the same source. The use of PAP smears in this way is seen as a valuable resource in cases where positive identification using traditional dental and medical records is not possible.     

Antemortem records of forensic significance among edentulous individuals

The identification of edentulous individuals is problematic due to poor provision of labelled dental prostheses. Dental records may still provide useful information for odontologists in the comparative identification process. The purpose of this study was to determine the level of forensically significant information contained within the dental records of a population of denture wearers attending the University of Manchester School of Dentistry. Two hundred and two dental records were examined and a proforma completed. The mean age of the patients was 72 years. Medical history were absent in 4% of all records and only 67.8% of the written records were rated as good. Thirty-two percent of the records contained one or more panoramic radiographs but 30% of these were over 3 years old rendering their usefulness in identification procedures questionable. In total only 18% of the examined records contained antemortem information that would enable identification. These data suggest that the process of denture marking is an essential in order to ensure that the identification of this population can be undertaken expediently by dental means.     

Dental hygiene students' matching accuracy when comparing antemortem dental radiographs and oral photographs to simulated postmortem WinID3® odontograms

Matching dental antemortem (AM) and postmortem (PM) data for human identification is especially challenging when the workforce is limited. Dental hygienists have served mass fatality incidents (MFIs) due to dental-related expertise. However, forensics within dental hygiene education and research on transferable skills is limited. This qualitative balance design study assessed senior dental hygiene students' match accuracy of simulated cases varying in dental identifiers based on AM full mouth series (FMS) radiographs and oral photographs to PM WinID3^® odontograms to demonstrate possible disaster victim identification (DVI) transferable skills gained during formal education. A convenience sample of senior dental hygiene students (n = 31) was presented information on WinID3^® interpretation, then presented with 5 mismatched cases and asked to visually interpret each to make 10 total matches; five based on AM FMS with simulated PM WinID3^® odontograms and five based on AM photographs with PM WinID3^® odontograms. Match accuracy scores ranged from 41.9% to 58.1% for cases with 1–10 identifiers, and 77.4% to 93.5% for cases with 11–40 identifiers. Accuracy when matching AM radiographs to PM odontograms versus AM photographs to PM odontograms was compared and revealed no statistical differences in match accuracy depending on image type (p = 0.388 to 1.000). Results of this pilot study suggests transferable match accuracy skills resulted from the participants' dental hygiene formal education. These baseline skills with additional specialized training support the rationale for dental hygienists serving on DVI teams. More research is needed in education and practice when preparing dental hygienists for forensic-based service.