Bite Marks: Indispensable Forensic Evidence

Introduction: Forensic odontology involves the collection, management, interpretation, evaluation, and presentation of dental evidence for criminal or civil legal proceedings, a combination of various aspects of the dental, scientific and legal professions. Bite mark analysis is an essential aspect of it that can significantly impact the courtroom or when considering the care of children and women deemed at risk. Materials and Methods: Data were obtained and analyzed from previously published literature and electronic database searches of relevant published literature from PubMed and Google Scholar. Forensic odontologists examine, interpret, analyze, and prepare reports on bruises or marks thought to be caused by teeth and, on occasion, are cross-examined in a court of law. Hence, they are considered essential in forensic dentistry in solving crimes to find either suspects or even victims in self-inflicted injuries as they are caused either by humans or animals that reveal biting edges, spacing, restorations, missing teeth, broken teeth, or supernumerary teeth unique to that individual. The main reasons for causation are sexual crimes, homicides, child abuse, and violent fights. There are many methods to analyze, that are classified into manual, semi-automatic, and automatic methods. Objectives: This review highlights the bite marks in detail about their characteristics, methods of collection and different methods of analysis and its applications in forensic odontology. Conclusion: This review shows different methods of analyzing bitemarks and explains the advantages, disadvantages, and limitations, and identifies which method is better advisable and adaptableforanalysis.

Patrones morfológicos erróneamente diagnosticados como huellas de mordedura en contextos forenses: una revisión con búsqueda sistemática / Morphological patterns misdiagnosed as bite marks in forensic contexts: a scoping review

RESUMEN: El análisis de huellas de mordedura para identificación forense puede ser clave para establecer la inocencia o culpabilidad del acusado. Sin embargo, esta evidencia ha sido cuestionada por su falta de consenso y objetividad, y por sus reportadas identificaciones erróneas. Se presenta una revisión con búsqueda sistemática de casos indicando errores diagnósticos y sus caracterizaciones, y se discuten las recomendaciones realizadas para evitarlos. Se utilizó la estrategia ("bite mark" OR "bitemark") AND ("artefactual" OR "misidentification" OR "misdiagnosis" OR "mistake"), incluyendo casos de huellas de mordedura humana en piel con reportes de errores diagnósticos, excluyendo diseños experimentales, huellas en alimentos u objetos. Fueron seleccionados un total de 13 documentos reportando 21 casos, abarcando los años 1989 a 2014. Los patrones morfológicos con mayor reporte de error diagnóstico fueron los producidos por trauma cortante o contuso por otras causas (10 casos), seguidos de los producidos por condiciones médicas y tratamientos de emergencia (6 casos). Al menos tres de los casos tomaron estado público, dos de ellos con sentencia de muerte y uno con condena de 25 años a prisión perpetua. Se ha enfatizado el dar minuciosidad y estandarización a la evaluación morfológica de este tipo de evidencias por la importante cantidad de condenas erróneas. Esta revisión pone en evidencia la escasa exposición y análisis de estos errores, con la insuficiente información para un aprendizaje significativo crítico y diseño de herramientas para evitarlos. Se coincide en la necesidad de estandarizar y optimizar protocolos para estas evidencias y adoptar una conducta reflexiva para sus análisis con fines de identificación forense.

SUMMARY: Bite mark analysis for forensic identification can be key to establishing the innocence or guilt of the defendant. However, this evidence has been challenged for its lack of consensus and objectivity, and its reported misidentifications. We present a scoping review of cases indicating misidentifications and their characterizations, and recommendations for avoid them are discussed. The strategy ("bite mark" OR "bitemark") AND ("artifactual" OR "misidentification" OR "misdiagnosis" OR "mistake") was used, including cases of human bite marks on skin with reported misdiagnosis, excluding experimental designs, bite marks on food or objects. A total of 13 documents were selected reporting 21 cases, covering the years 1989 to 2014. The morphological patterns with the highest report of misdiagnosis were those produced by cutting or blunt trauma due to other causes (10 cases), followed by those produced by medical conditions and emergency treatments (6 cases). At least three of the cases became public, two of them with a death sentence, and one with a 25-year sentence to life in prison. The thoroughness and standardization of the morphological evaluation of this type of evidence has been emphasized due to the significant number of erroneous convictions. This review highlights the scarce exposure and analysis of these errors, with insufficient information for critical meaningful learning and the design of tools to avoid them. There is agreement on the need to standardize and optimize protocols for these evidences and adopt a reflective behavior for their analysis for forensic identification purposes.

Metodología de Binford para la categorización tafonómica de marcas de dientes animales en superficies óseas: una revisión con búsqueda sistemática / Binford methodology for taphonomic classification of animal tooth marks on bone surfaces: a systematic search review

La Tafonomía, concepto reconocido en paleontología y antropología, permite estimar tiempo y circunstancias de muerte mediante el estudio de condiciones post-mortem y factores relativos a la supervivencia de restos óseos. Entre las diferentes variables tafonómicas, Binford (1981) propuso una categorización de marcas de mordedura, hoy reconocido estándar para estos estudios. Sin embargo, su diseño original en inglés podría llevar a malinterpretaciones o informes erróneos por no poseer una traducción validada. Se realizó una revisión con búsqueda sistemática de artículos en español, sin límite temporal, que citaran a Binford ("Bones: Ancient Men and Modern Myths") en Google Scholar. Fueron incluidos aquellos que mencionaran esta metodología para categorizar marcas de mordedura como agente tafonómico. Se excluyeron tesis, libros, pósters y resúmenes de congresos. Se identificaron 349 documentos y se seleccionaron 83 según criterios. El 65,12 % refirió sólo a huellas de mordedura animal sin especificar categorías; el 26,51 % mostró traducciones libres o categorizaciones parciales, y el 8,43 % realizó categorizaciones sin traducción. La mayor cantidad de citas fueron realizadas por autores de Argentina y España (54,22 % y 24,10 % respectivamente, como única filiación). Las categorías con más traducciones libres fueron "pitting" y "puncture" (11 y 8 términos diferentes respectivamente). Si bien la categorización de Binford es citada profusamente en países de habla hispana para definir las marcas de mordedura animal en hueso, la ausencia de transculturización conlleva falta de consenso para la comunidad científica. Más allá de una traducción literal, la adaptación y estandarización de estos términos es necesaria para validar esta metodología.

Taphonomy, a concept recognized in paleontology and anthropology, allows the estimation of time and circumstances of death by studying post-mortem conditions and factors related to the survival of bone remains. Among the different taphonomic variables, Binford (1981) proposed a categorization of bite marks, now recognized as standard for these studies. However, its original design in English could lead to misinterpretations or erroneous reports for not having a validated translation. A scoping review was conducted for articles in Spanish, without a time limit, that cited Binford ("Bones: Ancient Men and Modern Myths") in Google Scholar. Those who mentioned this methodology to categorize bite marks as taphonomic agent were included. Theses, books, posters and conference proceedings were excluded. We identified 349 documents, and 83 were selected according to criteria. 65.12 % referred only to animal bite marks without specifying categories; 26.51 % showed free translations or partial categorizations, and 8.43 % made categorizations without translation. The largest number of citations were made by authors from Argentina and Spain (54.22 % and 24.10 % respectively, as the only affiliation). The categories with the most free translations were "pitting" and "puncture" (11 and 8 different terms respectively). While Binford's categorization is widely cited in Spanish-speaking countries to define animal bite marks in bone, the absence of transculturation implies a lack of consensus for the scientific community. Beyond a literal translation, the adaptation and standardization of these terms is necessary to validate this methodology.

Morphometric analysis of bite mark patterns caused by domestic dogs ( Canis lupus familiaris ) using dental wax registers / Análisis de patrones de huellas de mordedura producidos por perros domésticos ( Canis lupus familiaris ) utilizando registros en cera dental

Dog bites are a known public health problem involving physical, mental and emotional traumas. From a forensic point of view, it has been stated that their morphological characters, and the intercanine and interincisive measurements, could allow a taxonomic and specific identification of the implicated animal. The aim of this study was to differentiate and identify the biological profile of a potential aggressor dog by analysing eight morphometric bite patterns belonging to three different dog breeds. The data obtained were analyzed following three categories: a) breeds; b) sexes among breeds; and c) sex within breed. Significant differences were detected among the variables (p≤ 0.05), but only the maximum maxillary intercanines width (MaxCW) allowed a breed differentiation. The other variables allowed a differentiation between two breeds or one breed over the others. The principal components analysis (PCA) allowed visualizing the degree of dispersion and relationship among the scores. It showed three well-defined and separated breed groups, and different degrees of dispersion within and among breeds. The most important variable for such a differentiation was MaxCW. When considering sex among breeds for males, it showed a statistically significant difference, but only the diastema located between the third left mandibular, incisive and the left mandibular canine (C-I-ManL) allowed breed differentiation. For females, only MaxCW allowed a differentiation among breeds. The multivariate analysis permitted with a 95 % confidence interval, a breed and sex differentiation. Besides, the PCA models allowed classifying, identifying, separating and graphically showing the relationship among the variables. This made it possible to differentiate between breeds and sexes. Due to the large range of dog breeds around the world, this multivariate analysis could also help determining the dog's weight and size, narrowing down towards an approximate number of offending dogs, focussing on a certain kind of dog breed, and pinpointing any suspect dog.

Las mordeduras de perros son un conocido problema de salud pública que involucra traumas físicos, mentales y emocionales. En la faz forense, se ha establecido que características morfológicas, así como las medidas intercanina e interincisiva, permitirían una identificación taxonómica y especifica del animal involucrado. El objetivo fue diferenciar e identificar el perfil biológico de un potencial perro agresor analizando ocho patrones morfológicos de mordeduras pertenecientes a tres diferentes razas caninas. Los datos fueron analizados considerando tres categorías: a) razas; b) sexo entre razas; y c) sexo en cada raza. Se observaron diferencias entre las variables (p≤0,05), pero sólo la distancia máxima entre caninos maxilares (MaxCW), permitió una diferenciación entre razas. Las otras variables permitieron una diferenciación entre dos razas o de una raza sobre las otras. El análisis de componentes principales (PCA) permitió visualizar el grado de dispersión y la relación entre las puntuaciones (dentro y entre razas). Se observaron tres grupos (razas) bien definidos y separados con diferentes grados de dispersión dentro y entre razas. La variable más importante para tal diferenciación fue la MaxCW. Al considerar sexo (machos) entre razas, se encontró diferencia estadísticamente significativa, pero sólo la medida del diastema localizado entre el tercer incisivo y canino izquierdo mandibulares (C-I-ManL) permitió la diferenciación entre razas. Para hembras, sólo la MaxCW permitió una diferenciación entre razas. El análisis multivariante permitió, con un intervalo de confianza del 95 %, diferenciar raza y sexo. El modelo PCA permitió además clasificar, identificar, separar y mostrar gráficamente la relación entre las variables. Esto posibilitó diferenciar entre razas y sexos. Debido a la gran variedad de razas de perros en el mundo, este análisis multivariado permitiría estimar peso y tamaño del animal, indicando un número aproximado de perros atacantes, centrándose en ciertos tipos de raza, y localizar a cualquier cánido sospechoso.

Teeth in forensics: A review

With the ever-increasing crime rate in our society, the field of forensic sciences has become highly evolved. Forensic dentists play a pivotal role in various areas of crime scene investigations and thereby help solve innumerable mysteries. Teeth appear to be vital pieces of evidence in several such investigations. Teeth are preserved in the closed cavities of the mouth and are generally resistant to the threatening environmental conditions that may be associated with the death of an individual, making them very useful in postmortem analysis. Teeth thus obtained may be useful in age estimation of the deceased victim or in determining his blood group. Identification of individuals in mass disasters can also be performed based on the unique morphological characteristics of the human dentition and through dental DNA fingerprinting. Again teeth play an all important role in catching a culprit through the positive correlation of the bite marks left behind at the crime scene and the suspect's own teeth marks. Thus, teeth prove to be an important adjunct in forensics. Its scope is ever-increasing with time, and a great amount of research is being carried out to implement the same. A PubMed, MEDLINE, and Scopus search was conducted of the past 70 years using several search terms like “Forensic odontology,” “history of forensic odontology,” “dental DNA fingerprinting,” “forensic age estimation,” “age estimation from teeth” and “bitemarks.” Other articles and textbook references which were considered to be important were also included in this study. The articles gathered were divided into the following groups: history of forensic odontology, teeth and DNA (dental DNA fingerprinting), teeth and blood grouping, teeth and age estimation, and teeth in bite marks.

Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788), in an equatorial insular breeding ground

Mating events and aggregations of vulnerable nurse sharks Ginglymostoma cirratum were recorded in the insular protected area of Fernando de Noronha (FEN), Brazil, between April and August 2015. Female sharks were observed clustering in groups of up to 14 individuals in shallow water adjacent to the shore. Several evasive mating behaviours in the presence of males were noticed, including shoreward movement, positioning ventral side up at the sea surface with emerged pectoral and pelvic fins, body rolling and caudal fin thrashing. Fresh bite marks indicative of male courtship and coupling attempts were visible in female's pectoral and caudal fins. Altogether, the observed behaviours match previous reports of non-cooperative female nurse sharks during mating opportunities. An extended mating season coupled with a persistent use of inshore habitats result in nurse sharks being particularly vulnerable to human pressure during a most sensitive stage of their life cycle. The effective conservation of nurse shark populations from the western South Atlantic may thus depend on the protection of critical habitats where this species aggregates to reproduce. Explicitly addressing environmental requirements by vulnerable species in local management strategies is indispensable to ensure that human pressure, including ecotourism development, does not collide with stipulated conservation aims.(AU)

Agregações e eventos reprodutivos do vulnerável tubarão-lixa, Ginglymosytoma cirratum , foram registrados na área insular protegida do Arquipélago de Fernando de Noronha (FEN), Brasil, entre Abril e Agosto de 2015. Grupos constituídos por até 14 fêmeas foram observados em águas rasas adjacentes à linha costeira. Perante a presença de machos, diversos comportamentos evasivos por parte das fêmeas foram identificados, incluíndo movimentação para águas ainda mais rasas, posicionamento na superfície do mar com a face ventral orientada para cima e emersão das nadadeiras peitorais e pélvicas, enrolamento do corpo e batimento da nadadeira caudal na superfície do mar. Foram identificadas marcas recentes de mordida nas nadadeiras peitorais e caudais das fêmeas, sugerindo interações de acasalamento com machos. No geral, os comportamentos observados coincidem com os comportamentos exibidos por fêmeas não aquiescentes à cópula reportados no hemisfério norte. Em FEN, a duração relativamente longa do período de acasalamento, juntamente com a utilização persistente dos habitats mais costeiros, promovem a vulnerabilidade do tubarão lixa às pressões antrópicas durante uma das fases mais sensíveis do seu ciclo de vida. A conservação efetiva das populações de tubarão-lixa do Oceano Atlântico Sul ocidental poderá, assim, depender da proteção dos habitats críticos de agregação onde esta espécie se reproduz. Por conseguinte, a abordagem explícita dos requisitos ambientais associados a espécies vulneráveis no âmbito dos planos de manejo locais deve ser considerada como indispensável para assegurar que as pressões antrópicas, incluíndo o desenvolvimento ecoturístico, não comprometerão os objetivos conservacionistas estipulados.(AU)

An overview of Bite mark analysis.

Human bite mark analysis is by far the most demanding and complicated part of Forensic Dentistry. Although bite marks of an individual do have uniqueness due to specific characteristics and arrangement of the teeth, when it comes to bite mark analysis, it is complicated by numerous factors, being presented as a challenge to the Forensic Odontologists. 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 protocol for collection, management, preservation, analysis and interpretation of this evidence should be employed if useful information is to be obtained for the courts. This article throws light on the details of evidence collection techniques and step by step method to analyse the bite mark injury. It also provides insight about the modern methods now implemented in the analysis of bite marks. Conclusions from the analysis of bite mark evidence can assist the justice system to answer crucial questions about interaction between people present at the scene of crime.

Comparison between five commonly used two-dimensional methods of human bite mark overlay production from the dental study casts.

Aim: The present study was conducted to determine the most accurate bite mark overlay fabrication technique by studying two physical characteristics, i.e., area and rotation of biting edges of anterior teeth of thirty volunteers. The objective of the study was to evaluate the reliability and efficacy of five commonly used methods of human bite mark overlays using two dimensional (2D) digital images of dental study casts as a gold standard, to rank different methods according to statistically based determination of relative accuracy of each method and to determine its feasibility in Forensic science. Materials and Methods: Overlays were produced from the biting surfaces of six upper and six lower anterior teeth of 30 volunteers using the following five methods: a) hand tracing from study casts, b) hand tracing from wax impressions, c) xerographic method, d) radiopaque impression method and e) 2D computer-based method. Area of the biting edges of the anterior teeth and relative rotation of each anterior tooth were measured and compared. Results: The xerographic method was determined to be the more accurate method with respect to tooth area and rotation. Hand tracing methods, from either wax impressions of teeth or directly from study casts, were determined to be inaccurate and subjective. Conclusions: It is recommended that forensic odontologists discontinue the use of hand tracing overlays in bite mark comparison cases as there is lot of scope for manipulation and observer bias.

Revenge by the bites.

Bite marks are important evidences, which are most often ignored by the investigating officers in India. Sometimes due to lack of this knowledge, let the culprit go Scot-free. Bite marks help to link the culprit with the crime. It is important scientific evidence, which if properly collected and analyzed can help, in successful prosecution of the case. Analysis of a case of bite marks is presented here by which culprit could be identified.