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Biomedical subjects

David Sweet

Publications and source records attributed to David Sweet.

11 recordsLinked to original sources
PubMed2006

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.

Asia, Southeastern↗
PubMed2005

A comparative reliability analysis of computer-generated bitemark overlays.

This study compared the reliability of two methods used to produce computer-generated bitemark overlays with Adobe Photoshop (Adobe Systems Inc., San Jose, CA). Scanned images of twelve dental casts were sent to 30 examiners with different experience levels. Examiners were instructed to produce an overlay for each cast image based on the instructions provided for the two techniques. Measurements of the area and the x-y coordinate position of the biting edges of the anterior teeth were obtained using Scion Image software program (Scion Corporation, Frederick, MD) for each overlay. The inter- and intra-reliability assessment of the measurements was performed using an analysis of variance and calculation of reliability coefficients. The assessment of the area measurements showed significant variances seen in the examiner variable for both techniques resulting in low reliability coefficients. Conversely, the results for the positional measurements showed no significant differences in the variances between examiners with exceptionally high reliability coefficients. It was concluded that both techniques were reliable methods to produce bitemark overlays in assessing tooth position.

Bites, Human↗
PubMed2003

Adherence of forensic odontologists to the ABFO guidelines for victim evidence collection.

Certifying boards for different professions have the duty to help establish standards and guidelines for methodologies routinely performed within the discipline. For forensic dentists, this responsibility is placed upon the American Board of Forensic Odontology (ABFO). The purpose of this study was to examine whether board certified and noncertified forensic odontologists adhere to the ABFO Guidelines outlined in the collection of victim bitemark evidence. A questionnaire was developed to assess the compliance and attitudes towards the typical evidence collected, the photographic documentation, and the handling of the bite site injury. The results indicate the majority of the respondents in both representative groups routinely follow the guidelines set forth by the ABFO. The lack of personally photographing the bite injury on a consistent basis is an area of concern for all examiners. The photographic evidence is an instrumental part of the investigation and often cannot be utilized due to improper procedures being followed. The film type utilized, bite site impression techniques, and excision of any tissue samples remain an individual choice and vary significantly among each forensic odontologist.

Bites, Human↗
PubMed2003

Quantification of forensic DNA from various regions of human teeth.

When the use of traditional forensic identification methods such as fingerprints or dental radiographs is difficult or impossible, identification by DNA analysis has proven valuable. In situations such as explosions or airplane crashes, identification is even more difficult because human remains are often fragmented and may be commingled. Teeth are a useful source of DNA and can often survive extreme environmental conditions. However, teeth may be fragmented into several identifiable regions. Therefore it is important to determine if DNA is present in forensically significant yields in all regions of the tooth. The main objectives of this study were to determine which region(s) of the tooth contains quantifiable DNA, if all regions contain similar yields of DNA and whether there is enough DNA in all regions to justify DNA extraction from a found tooth fragment. Results demonstrate that there is sufficient quantity of DNA in the crown body, root body, and root tip to support DNA extraction. Additionally, the root body is the region with the highest yield of DNA. This information will aid forensic DNA analysts in producing a useful DNA profile in a timely and cost-effective manner.

Adult↗
PubMed2003

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.

Analysis of Variance↗
PubMed2002

Forensic implications of biting behavior: a conceptually underdeveloped area of investigation.

Within the context of a criminal investigation the human bitemark traditionally provides the forensic dentist with both physical and biological evidence. In recent years, however, examples exist where in addition to discussing physical and biological evidence, expert witnesses have also testified in court regarding the behavioral aspects of biting behavior. Interested in this additional source of evidence, the authors reviewed the research literature from which biting behavior could be explained. The review found a hiatus of empirical knowledge in this respect, with only two papers seemingly related to the topic. With this dearth of knowledge in mind, the authors present a framework for further analysis and tentatively suggest reasons for biting behaviors, using a range of psychological models. The article ends with a cautionary note that vague and often misleading behavioral assumptions must not be applied to bitemark testimony until further data are available.

Aggression↗
PubMed2002

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.

Accidents, Aviation↗