Bite-Mark and Pattern Injury Analysis: A Brief Status Overview.

Bite marks are one component of forensic investigation requiring subjective interpretation for determining unknown source evidence to a putative suspect. Recent scrutiny has lead to questions about the scientific validity of patterned evidence, bite-mark analysis in particular, and its role in judicial proceedings. This article discusses some issues that persist in forensic circles and the difficulties surrounding the field of bite-mark analysis that inherently must employ human subjectivity in its execution of duty.

[The assessment of bite injuries from a forensic point of view]. / Die Beurteilung von Hundebissverletzungen aus gerichtsärztlicher Sicht.

The identification of a bite injury and its differentiation between human and animal origin demand a high level of special knowledge from the examining physician. The evaluation of bite injuries in terms of their hazard potential, risk profile and origin is usually done by a forensic specialist based on medical record documentation after immediate medical treatment. Therefore, as a first responder, a detailed documentation of the entire injury pattern is essential. If necessary, samples for further DNA analysis should be taken.The present article is intended to give a brief introduction to various aspects of bite injuries as well as to point out possibilities and limitations of the assessment of such cases.

Coincidence and awareness of oral parafunctions in college students.

OBJECTIVE: The aim of the study was to determine the prevalence and awareness of particular types of oral parafunctions in young healthy students and any association with temporomandibular disorders (TMD). MATERIAL AND METHODS: The study was performed in a randomly selected group of 303 healthy students (mean age 18.8 years) from the vocational technical school in Wroclaw, Poland, who underwent a routine clinical examination and functional analysis of the mouth. On taking the history all subjects were asked about their awareness of various forms of parafunctional activity in their mouth. RESULTS: Almost all subjects revealed various oral parafunctions such as: bruxism, nail and pen biting, chewing gum, and biting the mucosa of lip or cheek. These habits were present singly or as double, triple or even fourfold coincidences in a single person. The most frequent oral parafunctions were habitual gum chewing and bruxism. Subjects were very seldom aware of the last parafunction. TMDs were more prevalent in the presence of bruxism than in other oral parafunctions. CONCLUSIONS: The studied students revealed various types of oral parafunctions, however most of them were not aware of clenching and grinding their teeth.

Forensic odontology, part 4. Human bite marks.

The aim of this paper is to give a brief overview of bite mark analysis: its usefulness and limitations. The study and analysis of such injuries is challenging and complex. The correct protocols for collection, management, preservation, analysis and interpretation of this evidence should be employed if useful information is to be obtained for the courts. It is now possible, with advances in digital technology, to produce more accurate and reproducible comparison techniques which go some way to preventing and reducing problems such as photographic distortions. Research needs to be continued to increase our knowledge of the behaviour of skin when bitten. However, when presented with a high quality bite mark showing good dental detail, and a limited, accessible number of potential biters, it can be extremely useful in establishing a link between the bitten person and the biter or excluding the innocent.

Biomechanical approach to human bitemark reconstruction.

UNLABELLED: This paper investigates the changes in upper and lower dental bite records that occur when the anterior teeth occlude into a three-dimensional rather than a flat object. METHODS: anterior bite registrations were obtained from 20 volunteers with full and unrestored dentitions. As a three- dimensional, life-like bite target we cast a silicone replica from the impression of an actual arm, fitted with a rigid bony interior. Each participant was asked to bite into a single layer of softened bite registration wax wrapped around the same location on the fake arm, as well as into a flat wafer of the same material. Upper and lower bite registrations were then scanned in the same location on a flat bed scanner. We analysed the sizes of the different bite marks by means of landmark- and semi-landmark analysis to calculate Procrustes distances between tooth outlines. In order to analyse shape variation between the two types of bite registration we carried out principal components analyses on the partial warp scores. These were derived from partial Procrustes coordinates aligned by means of thin-plate spline decomposition based on a bending energy matrix. Our results show that there are significant differences in the shape of the upper or lower teeth when they occlude into a flat or three- dimensional target. We conclude that the use of a traditional flat bite registration in human bitemark reconstruction and analysis has to be seriously questioned.

Forensic dentistry: 2. Bitemarks and bite injuries.

UNLABELLED: While the practice of human identification is well established, validated and proven to be accurate, the practice of bitemark analysis is less well accepted. The principle of identifying an injury as a bitemark is complex and, depending on severity and anatomical location, highly subjective. Following the identification of an injury as a bitemark, the comparison of the pattern produced to a suspect's dentition is even more contentious and an area of great debate within contemporary odontological practice. Advanced techniques using digital overlays have been suggested, yet studies have shown that these can be inaccurate and there is no agreement as to the preferred method of comparison. However, the advent of DNA and its recovery from bitemarks has offered an objective method of bitemark analysis. Despite the strengths of DNA, the physical comparison of a suspect's dentition to bitemark injuries is still commonplace. The issues within bitemark analysis are discussed and illustrated with case examples. CLINICAL RELEVANCE: Dentists should be aware of where bitemarks are most commonly found, and of their significance in cases of children, the elderly and spousal abuse.

Clinical and histopathological examination of experimental bite marks in-vivo.

Under rigorously controlled laboratory conditions, mechanically induced simulated human bite marks were made on pig skin to enable the clinical and histopatholgical study of experimental bite marks in-vivo. A series of bite marks were created on the abdomen and thorax of live anaesthetized juvenile pigs at specific times just prior to and after death. Following the release of the biting force clinical observations of antemortem wounds revealed slow diminishment of the bite indentations presumably due to dermal elastic recovery. Minutes after euthanasia of the animals, the indentations of the teeth from the postmortem bite marks faded rapidly. After the biting process the animals were placed on either the right or left side and this side was maintained until necropsy to examine for dependant and non-dependent side differences. All bite mark injuries located on the non-dependent side revealed specific pattern characteristics. However, on the dependent side whether the bite mark was antemortem or postmortem in areas of livor mortis, no clear pattern was visible. Histologically, the observations for each bite mark specimen were categorised by the presence or absence of extravasated red blood cells in the fatty or muscle layers. The histopathological findings correlate with the clinical observations of antemortem and postmortem bite marks located on the non-dependent side in regard to muscular erythema and extravasated red blood cells. It is clinically difficult to comment on temporal relationship of a bite mark in relation to time of death in areas affected by blood-pooling seen on the dependent side. In these situations, histopathological studies could be a reliable alternative to provide information regarding antemortem or postmortem injuries.

Computer-based production of comparison overlays from 3D-scanned dental casts for bite mark analysis.

Bite mark analysis assumes the uniqueness of the dentition can be accurately recorded on skin or an object. However, biting is a dynamic procedure involving three moving systems, the maxilla, the mandible, and the victim's reaction. Moreover, bite marks can be distorted by the anatomic location of the injury or the elasticity of the skin tissue. Therefore, the same dentition can produce bite marks that exhibit variations in appearance. The complexity of this source of evidence emphasizes the need for new 3D imaging technologies in bite mark analysis. This article presents a new software package, DentalPrint (2004, University of Granada, Department of Forensic Medicine and Forensic Odontology, Granada, Spain) that generates different comparison overlays from 3D dental cast images depending on the pressure of the bite or the distortion caused by victim-biter interaction. The procedure for generating comparison overlays is entirely automatic, thus avoiding observer bias. Moreover, the software presented here makes it impossible for third parties to manipulate or alter the 3D images, making DentalPrint suitable for bite mark analyses to be used in court proceedings.

Bite marks--the criminal's calling cards.

Carnivorous animals, like dogs or tigers, use their teeth in two distinct ways. They kill their prey primarily using their canines and they tear and slice the flesh to produce digestible fragments. Human teeth are designed principally to cut and grind food which is usually previously prepared. Some people appear to revert to more primitive instincts and use their canines and incisors to inflict bites on unsuspecting victims.

Management of human bite injuries of the hand.

On the basis of experience at the Ottawa Civic Hospital over the past 10 years, a classification of and protocol for the management of human bite injuries of the hand are presented. Early exploration of such wounds under local anesthesia improves the outcome by facilitating adequate cleansing of the wound and enabling deep structures to be visualized. In this way the risk of major sepsis and of the disability so frequently associated with these innocent-looking injuries can be reduced.