Lack of dental uniqueness between two bite mark suspects.

The central dogma of bite mark analysis is based upon two assumptions. The first is that human teeth are unique, and the second is that sufficient detail of the uniqueness is rendered during the biting process to enable identification. Both of these assumptions have been challenged over recent years, and a healthy scientific skepticism surrounding bite mark analysis has developed. The case presented features two suspects whose dental arrangement was similar and, when compared to the bite mark, both demonstrated consistent features. Within a closed population of possible biters, one of the two suspects was responsible for the injury. The case is illustrated with photographic and overlay detail of the suspect's teeth and demonstrates the complexity of such cases. The authors call for greater caution when drawing conclusions from such cases and highlight the need for further research into the replication of dental features on human skin.     

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.     

A comparison of the ability of experts and non-experts to differentiate between adult and child human bite marks using receiver operating characteristic (ROC) analysis

Fifty colour prints of human bite marks were sent to 109 observers who were asked to decide using a six point rating scale, whether the marks had been produced by the teeth of an adult or a child. The observers consisted of accredited senior forensic dentists, accredited junior forensic dentists, general dental practitioners, final year dental students, police officers and social workers. The results were compared against a “gold standard” which was the actual verdict from the case. Comparison of the results between the groups of observers and the standard was made using Receiver Operating Characteristics (ROC) methodology. The best decisions were made by senior/junior experts or final year dental students. General dental practitioners and police officers were least able to differentiate correctly between adult and child bite marks. The effect of training is important and its effects need to be assessed in more detail in future studies.     

Uniqueness of the Dentition as Impressed in Human Skin: A Cadaver Model*

Abstract: Bitemark interpretation assumes that the human dentition is unique and that its attributes can be accurately transferred to skin. A cadaver model was used to investigate whether the correct biter could be determined from similarly aligned dentitions once the dentitions were impressed in human skin. One‐hundred dental stone models, which were measured and determined to be unique, were divided into 10 groups based upon similarities of mal‐alignment patterns. One model was randomly selected from each group and bites were produced on unembalmed human cadavers. Metric/angular measurements and hollow volume overlays of the models were compared with the bites made. The percentage of dentitions from each group as well as the 100 dental model population that could not be excluded as the biter was determined. Results showed difficulty distinguishing the biter from individuals with similarly aligned dentitions and in some cases, an incorrect biter appeared better correlated to the bite.     

An elliptical incised wound of the breast misinterpreted as a bite injury

Bite injuries upon homicide victims are most often initially identified by the forensic pathologist during the course of the autopsy examination. Following such recognition, the injury or photographs of the traumatized site are then referred to a forensic odontologist for his or her examination, further characterization, and subsequent comparison with any suspect's dentition. However, if the pathologist misidentifies an injury caused by another mechanism as a human bite, this mistake can potentially be perpetuated by the dental consultant, since relatively few dentists regularly examine traumatic injuries other than those arising from bites. To illustrate such an event, a case is presented involving an incised wound of the breast, which was originally identified as an avulsive bite wound. Detailed examination by two odontologic consultants confirmed the wound as having been caused by human teeth, and further, they related the "bite injury" to a specific individual. The bite injury interpretation represented the only scientific evidence implicating the suspect at a subsequent trial for capital murder. Later examination of the tissues and photographs by a forensic pathologist and another dental consultant revealed that the injury was not due to human dentition, but rather resulted from a sharp-edged instrument. These consultants conducted a unique experiment to reduplicate the injury and prove its causation. This information was presented to the jury during the suspect's trial and resulted in his acquittal on all charges.     

Dog saliva transmitted pathogens as etiology of fatal infections (on the topic of causal relationship)

The authors report on 4 deaths. 3 of the victims had been bitten by dogs shortly before death; in one case the victim had close contacts with a dog. In 3 of the cases death was caused by septicemia; microorganisms occurring in the saliva of dogs, but rarely causing infection could be determined in 2 of the cases. While in case 1 there was no bite injury so that transmission must have occurred by droplet infection (without trauma) or via a discrete skin lesion, case 2 showed a penetrating dog-bite injury; in both cases the spleen had been surgically removed some years before. In case 3 a causal relationship had to be assumed between a dog bite and death, although no pathogen could be identified in microbiological tests. In case 4 death was not attributable to the dog-bite injury suffered, but was due to an internal pathological cause.     

Inquiry into the Scientific Basis for Bitemark Profiling and Arbitrary Distortion Compensation

Abstract: Prediction of dental characteristics from a bitemark (bitemark profiling) and arbitrary photographic distortion compensation are two practices proposed in bitemark analysis. Recent research on the effect of inherent skin tension properties in bitemark analysis suggests that these practices are subject to review. A biting apparatus was used to create 66 bitemarks in human cadaver skin. The bitemarks were photographed, sized 1:1, and evaluated with Adobe Photoshop^®. Metric/angular measurements and hollow volume dental overlays were employed. Distortion produced was calculated and assessed. Results showed distortional ranges were nonuniform both between bites, as well as within each bite. Thus, enlarging/decreasing the photograph uniformly would not correct the distortion that resulted. With regard to bitemark profiling, 38% of the bites created patterns that could be misleading if profiled. Features were present/absent that were inconsistent with the biter’s dentition. Conclusions indicate bitemark profiling and arbitrary distortion compensation may be inadvisable.     

An integrated technique for the analysis of skin bite marks

The high number of murder, rape, and child abuse cases in South Africa has led to increased numbers of bite mark cases being heard in high courts. Objective analysis to match perpetrators to bite marks at crime scenes must be able to withstand vigorous cross-examination to be of value in conviction of perpetrators. An analysis technique is described in four stages, namely determination of the mark to be a human bite mark, pattern association analysis, metric analysis and comparison with the population data, and illustrated by a real case study. New and accepted techniques are combined to determine the likelihood ratio of guilt expressed as one of a range of conclusions described in the paper. Each stage of the analysis adds to the confirmation (or rejection) of concordance between the dental features present on the victim and the dentition of the suspect. The results illustrate identification to a high degree of certainty.     

Use of an acrylonitrile-butadiene-styrene (ABS) plastic ring as a matrix in the recovery of bite mark evidence

Valuable forensic information can be obtained from analysis of human bite mark injuries after careful retrieval of such evidence from living or deceased victims. It is difficult, however, to maintain the anatomical configuration of the skin, especially where body contours complicate the recovery process. Transillumination of the injury pattern in the skin after removal and preservation of the tissue from a deceased victim can provide significant information in the investigation process. A dimensionally stable matrix is required to support the skin's anatomical configuration during and after its removal. The authors have developed a unique and convenient method of heating and contouring a ring of acrylonitrile-butadiene-styrene (ABS) plastic using table salt over a heat source. When this ring is applied to the deceased victim's skin, and a backing material is added for support, removal of the skin and the bite mark can be accomplished more predictably while maintaining the anatomical contour. It is important to record bite marks accurately as soon after discovery as possible; the authors believe that this technique will significantly aid recovery of such evidence either at the crime scene or in the laboratory. A method of inscribing appropriate anatomical markers and case numbers on the rings is also described.     

Bite Mark Analysis in Foodstuffs and Inanimate Objects and the Underlying Proofs for Validity and Judicial Acceptance

Even though one of the first bite mark cases was Doyle v. State in 1954 (a bitten cheese case), the research has focused on bite marks inflicted in human skin. As published Papers, Case Reports, or Technical Notes can constitute precedents which are relied upon in making the legal arguments and a considerable amount of case law exists in this area, we present a systematic review on bite mark analysis in foodstuffs and inanimate objects and their underlying proofs for validity and judicial acceptance according to Daubert rulings. Results showed that there is vulnerability in these procedures, and it is essential to demand for focus scrutiny on the known error rates when such evidence is presented in trials. These kinds of bite marks are well documented; however, there has been little research in this field knowing that the protocols of analysis and comparison are the responsibility of the forensic odontologists.     

A survey of the incidence of missing anterior teeth: potential value in bite mark analysis.

Bite mark analysis involves comparison of individual dental characteristics between a dentition and the bite injury. A bite mark injury may result from sexual assault, or physical assault, and defensive injuries, and as such can be used to link a suspect to a victim or vice versa. Missing teeth are one of the characteristics that could implicate or exclude a suspected biter. However frequency data for use by forensic odontologists can only be collated from epidemiological studies. Therefore an audit was undertaken of missing anterior teeth in adult patients (n = 1010) attending for treatment, gathering data that could be more relevant to odontology. One in five of the sample presented with missing teeth that were either replaced with a denture (11%), not replaced (6%) or missing with the gap closed (2%).     

Bite mark documentation and analysis: the forensic 3D/CAD supported photogrammetry approach

Bite mark identification is based on the individuality of a dentition, which is used to match a bite mark to a suspected perpetrator. This matching is based on a tooth-by-tooth and arch-to-arch comparison utilising parameters of size, shape and alignment. The most common method used to analyse bite mark are carried out in 2D space. That means that the 3D information is preserved only two dimensionally with distortions. This paper presents a new 3D documentation, analysis and visualisation approach based on forensic 3D/CAD supported photogrammetry (FPHG) and the use of a 3D surface scanner. Our photogrammetric approach and the used visualisation method is, to the best to our knowledge, the first 3D approach for bite mark analysis in an actual case. The documentation has no distortion artifacts as can be found with standard photography. All the data are documented with a metric 3D measurement, orientation and subsequent analysis in 3D space. Beside the metrical analysis between bite mark and cast, it is possible using our method to utilise the topographical 3D feature of each individual tooth. This means that the 3D features of the biting surfaces and edges of each teeth are respected which is--as shown in our case--very important especially in the front teeth which have the first contact to the skin. Based upon the 3D detailed representation of the cast with the 3D topographic characteristics of the teeth, the interaction with the 3D documented skin can be visualised and analysed on the computer screen.     

Pulmonary thromboembolism following calf cellulitis: report of an unusual complication of dog bite.

We report a case of a 75-year-old woman who died of pulmonary thromboembolism following a dog bite to the calf. The bite caused laceration of the skin and gangrenous cellulitis of leg soft tissues. Six days after hospitalization, the patient died suddenly, despite early antibiotic and heparin administration. Postmortem examination revealed extensive thrombosis of the deep veins of the calf and massive thromboembolism of the main pulmonary arteries.     

Assignment of a bite-mark on the victim's skin to the dentition of the perpetrator by means of anomalies in the number and position of the frontal teeth

This report is about a bite mark on the breast of a female corpse. The woman had been killed by ligature strangulation at the age of 76 years. The investigation of the dental casts of a suspected man showed some anomalies in the dentition and orthodontic variations. A comparison of the bite mark with these anomalies demonstrated the correspondence of several details. Consequently, the probability that the suspect was responsible for the bite mark was regarded as being very high. During the further investigations the suspect admitted the offence including the bite injury to the breast. The authors emphasize the importance of an exact photographic documentation as an indispensable prerequisite for an odontological comparison.     

Death secondary to a donkey's bites

We present a unique case of death due to the assault and bites of a donkey on a 65-year-old man. The farmer, found dead in his farmyard, had a very deep wound in the anterior region of the neck, with a sharp transection of the trachea and severe bleeding by several minor vessels wall disruptions. The cause of death was established to be massive bleeding combined with asphyxia due to aspiration of the blood. Moreover, multiple contusions with associated skin abrasions and perforations were present. The general impression of the injuries was consistent with an animal's bite marks. Herbivorous or omnivorous bite attacks on humans are rare; instead, these animals attack by kicking, trampling, and kneeling, resulting in secondary blunt injuries. The donkey is usually a docile animal, but its behavior can be aggressive during the mating season, and the possibility of biting should not be underestimated, as illustrated by the 2 cases published previously as well as by the case presented here.     

Not all bite marks are associated with abuse, sexual activities, or homicides: a case study of a self-inflicted bite mark

A case of self-inflicted bite mark during an episode of myocardial ischemia is presented. Using current bite mark identification techniques, the bite mark was shown to be self-inflicted. Self-biting may be an emotional response to pain or a type of counterirritation to alleviate pain. The recognition and documentation of this unusual case of a self-inflicted bite mark was due to the cooperation of the forensic pathologist and forensic odontologist.     

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.]     

Peculiar circular and C-shaped injuries on a body from the sea

A case where a body with unusual circular injuries was found in the sea is presented. The victim was a 60-year-old woman who had been depressed and had attempted suicide before. She was missing for 6 days before the corpse was found. The body had several almost perfectly circular injuries and C-shaped incision injuries with almost circular flaps of skin. We concluded that the cause of the peculiar circular injuries might be bite marks of Isistius spp. (I. brasiliensis and/or I. plutodus), commonly known as cookie-cutter shark because of its very unusual feeding style.     

A framework for estimating probability of a match in forensic bite mark identification

In forensic dentistry, a human expert typically does the comparison and identification based on bite marks. Unlike DNA analysis, however, there is no quantitative basis with which to assign a probability for this given match. This paper proposes a framework for empirically estimating the probability of such a bite mark match and reports on initial experimental results. The methodology involved collection of dental population data (3D dental casts and bite mark images), image analysis for quantitatively measuring the degree of match (based on chamfer distance), and performing a logistic regression analysis using the collected population data to estimate the probability of match from the calculated degree of match. The model correctly predicted 35 of the 42 matches and 585 of the 588 mismatches. The method also has potential for use in other forensic applications in which the assignment of quantitative probabilities is important.     

A Morphological and Morphometric Study of Bite Marks Caused by Mice (Mus Musculus) on Different Baits for Forensic Purposes

In animal bites, the dental attributes can be fundamental in identifying the marks made by various species on different matrices. Although rodent bite marks have been studied in the context of postmortem interference, little research has used different baits to analyze these marks linking not only specific behavior patterns but also the possibility of structural damage. Twenty mice (Mus musculus) were exposed to different baits to study their bite marks in a controlled model. The known pattern of parallel and multiple grooves has been seen in all baits, but polyvinyl chloride and fiber‐optic cable were significantly different between each other and the other baits. Some baits showed patterns of anchorage of the upper incisors and space between the lower incisors when gnawing. This technical note represents a novel model of analysis where veterinarians and/or dentists may be asked to give an opinion on alleged animal bite marks.