Adherence of forensic odontologists to the ABFO bite mark guidelines for suspect evidence collection

Boards and associations within forensic science have long been accepted as vehicles for the development and dissemination of protocols and recommendations for practice. Recent controversies surrounding bite mark analyses have brought the methods and practices of forensic dentists to the attention of both the courts and the media. In the mid-eighties the American Board of Forensic Odontology developed guidelines for bite mark analysis in response to unfavorable commentaries on the discipline by legal observers. The purpose of this study is to examine the adherence of board certified and noncertified forensic dentists to the guidelines for collection of evidence from bite mark suspects. A questionnaire was employed during an American Academy of Forensic Sciences meeting. Results showed that, in general, when the odontologists collected evidence they did adhere to the guidelines, although collection of salivary samples was not common. Of concern is the large number of odontologists who do not collect their own evidence from suspects. Police officers or other individuals often perform this task and therefore the guidelines must be disseminated to these groups to ensure that the maximum yield is obtained from bite mark evidence. A review of the materials used to collect evidence is also included with details of applications in forensic science.     

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.     

Dental identification by comparison of antemortem and postmortem dental radiographs: influence of operator qualifications and cognitive bias

Dental forensic identifications based on comparison of antemortem and postmortem radiographs provide effective and reliable evidence. There are no standardized procedures for assessing similarities between different types of dental radiographs (e.g. orthopantomograms, bitewings, and periapical radiographs), and the operator's subjective judgment can considerably affect identification. The purpose of this study is to evaluate the potential influence of experts' qualifications, training, and cognitive bias on the accuracy of identification. Seventy-eight differently qualified and experienced experts underwent an identification test. The expert sample was composed of 10 specialists in emergency care (ER), 10 specialists in legal medicine (ML), 20 pregraduate dental students (STU), 12 dentists (DENT), 20 dentists educated in forensic odontology (DENT-TRA), and 6 experienced forensic odontologists (FOR). The simulated cases required participants to assess the possible matching of 42 postmortem intraoral radiographs with 16 antemortem panoramic radiographs. Accuracy and specificity for the different operator groups were as follows: ER, 0.76-0.70; ML, 0.76-0.88; STU, 0.89-0.82; DENT, 0.87-0.97; DENT-TRA, 0.88-0.92; and FOR, 0.97-1. As evidenced by high rates of accuracy and repeatability, the most experienced forensic odontologist consistently outperformed operators less or differently educated and trained, especially for difficult cases. In our sample, the dentists who received additional education in forensic odontology did not necessarily perform better than dentists who had not received this additional education. Some cognitive bias, mainly the so-called observer effect, emerged as a possible source of outcome variability among the operator groups.     

The emotional and psychological impact of mass casualty incidents on forensic odontologists

Motivated by the findings of a previous research project, 38 forensic odontologists with known occupational experience of mass casualty incidents completed a questionnaire designed to elicit both quantitative and qualitative data. The questionnaire sought to provide an insight into the psychological and emotional impact of conducting work of this nature. Two psychometric scales were included in the questionnaire, The Positive and Negative Affect scale (PANAS) and the Impact of Events Scale (IOE). In addition, a number of open-ended questions relating to the personal experiences of the respondent during the mass casualty incident were also included. Quantitative findings indicate that on the whole mass casualty incidents resulted in a positive experience for the respondents, although over a third reported being distressed, upset or irritable at some time during the event. Sense of achievement and camaraderie were among the qualitative themes elicited that help explain the positive reactions. Working conditions, politics and the ictims were cited as sources of negativity.     

Dentists' qualifications affect the accuracy of radiographic identification

This study assessed the effects of forensic odontologists' training and experience upon the accuracy of their dental radiographic identifications. Forty participating odontologists with various levels of training and experience completed a Web-based survey of their qualifications and then completed nine Web-based radiographic identification cases. They made their identifications using the American Board of Forensic Odontology Categories and Terminology for Body Identification. The results indicate that odontologists with high levels of training and experience performed significantly more accurately than those with lower levels. We conclude that high levels of training and experience in forensic odontology should be developed, maintained, and required of dentists who participate in a forensic team dealing with challenging identification cases.     

The reliability of digitized radiographs for dental identification: a Web-based study

In the era of Daubert and other judicial rulings pertaining to the acceptability of forensic evidence, it is increasingly important that experts are able to testify that their methods have been scientifically tested and that error rates and other factors relating to reliability have been published. The purpose of this study was to determine the reliability of digitized radiographic comparisons for the purposes of dental identification. Participants with various forensic backgrounds and experience levels were passively recruited to the website. Ten forensic identification cases composed of antemortem and postmortem dental radiographs were supplied to examiners using a bespoke website. Participants responded to the cases on two occasions after a one-month washout interval using the ABFO conclusion levels for forensic identifications. A total of 115 first attempts and 87 matched second attempts were received. Of the total responses, 72% were dentally trained respondents who had completed at least one forensic identification case; of these, 38% were experienced forensic dentists who had completed more than 25 identifications. Data relating to accuracy, intra- and inter-examiner agreement, and the effect of case difficulty are presented. Mean accuracy was 85.5% for all cases, with the experienced forensic dentists obtaining a 91% success rate. The inter-examiner agreement on the negative identification cases was classified as poor. The data suggest that dental identifications resulting from the comparison of postmortem and antemortem radiographs are valid, accurate, and reliable when undertaken by experienced odontologists.     

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.     

Evaluation of dental radiographic identification: an experimental study

The object of this study was to assess the value of dental radiographs for the purposes of personal identification in the absence of tooth restorations. 198 periapical and bitewing radio graphs were taken of teeth contained in 22 dry skulls obtained from the skull collection of the Royal College of Surgeons of Edinburgh. Each selected view was taken three times: by a scientist, a dentist and a dental radiographer. Each operator independently positioned the films, selected the exposure times and positioned the cone of the X-ray machine. Three groups comprising forensic odontologists, dental vocational trainees and dental trainee hygienists attempted to match the randomly mixed radiographs into sets of three. Success rates for matching radio graphs ranged from 63.6 to 100%. The average for forensic odontologists was 93.3%, vocational trainees 85.2% and hygienists 89.7%. Where forensic odontologists had both formal training and experience, or extensive experience without formal training, the success rate was 100%. Where there was formal training but little experience the success rate was lower. Participants believed that root morphology and alignment had been the greatest aid to matching and not crown morphology. The depth of knowledge of the viewer correlated poorly with the number of correct results, although the forensic odontologists achieved the highest success rate. Formal training, although highly desirable, is no substitute for practical experience. Root morphology and alignment were cited most frequently as facilitating matching.     

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.     

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.     

The use of quantitative light-induced fluorescence (QLF) to identify composite restorations in forensic examinations

There has been a large increase in the number of tooth colored restorations "white fillings" placed in recent years. An increased demand from the public for more aesthetic dental restorations causes a potential problem for forensic dentists who may find the fillings difficult to identify and hence include in postmortem odontograms. This has implications for the accuracy of dental identifications, particularly in situations where limited time is available for postmortem identification, e.g., mass casualty incidents. A new method for the detection of composite restorations is presented. Quantitative Light-induced Fluorescence (QLF) is a technique currently employed to detect small changes in enamel mineral content. An experiment was conducted to determine if the technique would afford a greater degree of contrast between composite and enamel and thus enable the accuracy of composite identification in enamel. Twenty-four previously extracted human premolars were gently cleaned with pumice and wet-and-dry paper. Twelve were subsequently randomly selected and restored on their buccal surfaces with Spectrum (a composite) following manufacturer's instructions. No attempt was made to color match the teeth and all were filled with shade B3. Twelve teeth were left unrestored. QLF and normal white light images were taken of both restored and non-restored surfaces with teeth wet and then dried. Ten forensic dentists were asked on two separate occasions (one month between each attempt) to indicate whether or not they thought the surface was: a) restored or b) unrestored. Results indicate that forensic dentists detected a significantly higher proportion (p<0.005) of filled surfaces with QLF.     

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.     

Reality bites--A ten-year retrospective analysis of bitemark casework in Australia

Criticism of forensic science, particularly that of bitemark analysis, has become increasingly common in the last decade. Much of the criticism directed at forensic odontology cites cases where miscarriages of justice have occurred when erroneous, over-confident or even false bitemark evidence has been tendered by odontologists. Despite Australia's own experience with such cases in the past, it is postulated that this does not represent the true nature of bitemark analysis as practiced by odontologists today-at least in this country. A review of 119 cases from the last 10 years confirms that 'identification' of a suspect is rarely, if ever, offered, and that conclusions reached by odontologists with respect to bitemark analysis are generally conservative. However, the results of this study also indicate that in a small but significant proportion of cases, there is still some tendency to reach conclusions that could be considered over-confident when considering the overall quality of the physical evidence offered. It is suggested that odontologists should avoid making conclusive remarks regarding the origin of the mark, or the identification of a perpetrator, when such comments are realistically precluded, given the low evidentiary value of the mark itself.     

Expert Interpretation of Bitemark Injuries—A Contemporary Qualitative Study

This study attempts to characterize the nature of disagreement among odontologists in determining the fundamental properties of suspected bitemark injuries. Fifteen odontologists were asked to freely comment on six images of supposed bitemarks. Qualitative analysis using a grounded theory approach revealed that practitioner agreement was at best fair, with wide‐ranging opinions on the origin, circumstance, and characteristics of the wound given for all six images. More experienced practitioners (>10 years) tended to agree with each other less than those who had 10 years or less experience in forensic odontology. The differences in opinions can be at least partly accounted for by the inconsistent nature of approaches used by different practitioners in assessing bitemark evidence. The results of this study indicate that more definitive guidelines as to the assessment of bitemarks as patterned injuries should be developed to ensure the highest possible level of practitioner agreement.     

Identification of a Carbonized Body Using Implanted Surgical Plates: The Importance of Computed Tomography

In addition to clinical examination, forensic odontologists can use diagnostic imaging as an auxiliary method for identification. This paper reports a case where forensic odontologists from the Afrânio Peixoto Legal Medicine Institute in Rio de Janeiro (Brazil) positively identified a carbonized and partially calcined body using oral and maxillofacial imaging. The cadaver showed several metallic plates fixed with metallic screws on bones of the neurocranium and viscerocranium. Family members provided spiral computed tomography scans of the skull and a panoramic radiograph that were acquired after an accident that required surgical procedures. Comparative analysis between the clinical exam and the maxillofacial images demonstrated complete coincidence, confirming the victim's identity. Dactyloscopy, which is the most commonly used method of identification, was not possible because of the body carbonization. Thus, diagnostic imaging, especially computed tomography, was essential for elucidation of this case.     

Modified intraoral film holders for postmortem identification.

To date there have not been any commercial dental X-ray film holders marketed to accommodate the special needs of forensic odontologists. Modification of standard Rinn XCP film holders by the investigators produced self-supporting film holders that do not require the active participation from the examinee. The modified film holders greatly simplify the operator's technique of exposing dental radiographs on cadavers.     

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.     

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.]