14 Importance of Dental Records in Forensic Odontology

An Introduction to Forensic Odontology

Forensic Odontology is a fascinating field. The identification action by teeth is not new and as far back as 66 A.D. This is a specialized subject which is very useful for identification of age of unidentified bodies, matching bite marks on the skin of rape and child abuse victims; and for DNA extraction from the tooth and saliva found on the body. The theory behind forensic dentistry is that no two mouths are alike (even identical twins are different), and that teeth, like tools, leave recognizable marks. Most often the role of the Forensic odontologist is to establish a person’s identity. Teeth, with their physiologic variations, pathoses and effects of therapy, record information that remains throughout life and beyond. The teeth may also be used as weapons and, under certain circumstances, may leave information about the identity of the biter.

Basis of Forensic Odontology

The most basic concept in forensic odontology is centred on a form of pattern recognition and comparison. This conclusion ultimately arrives at a comparison of the unknown pattern with a known pattern in order to determine the extent of similarity. Dental professionals have a major role to play in keeping accurate dental records and providing all necessary information so that legal authorities may recognize malpractice, negligence, fraud or abuse, and identify unknown humans. It can be used to identify crime victims or suspects. Investigator experience, knowledge, knowledge of testing methodologies, and decision analysis abilities, among other issues, all contribute to successful evidence evaluation and assessment.

Determining Identity through Dental Forensics

The dentition is significant in the human identification process, primarily because teeth and the jaw structures can resist even the most severe environmental conditions and trauma. This is so, particularly for the teeth, because of the inherent durability of the tooth enamel and of cementum. The identification of dental remains is of primary importance when the deceased person is skeletonised, decomposed, burned or dismembered. The principal advantage of dental evidence is that, like other hard tissues, it is often preserved after death. Even the status of a person’s teeth changes throughout life and the combination of decayed, missing and filled teeth is measurable and comparable at any fixed point in time.

Dental identification assumes a primary role in the identification of remains when postmortem changes, traumatic tissue injury or lack of a fingerprint record invalidate the use of visual or fingerprint methods. The fundamental principles of dental identification are those of comparison and of exclusion. For example, dental identification is used when ante mortem records for the putative deceased person are available and circumstantial evidence suggests the identity of the decedent, and when ante mortem records of other suspicious, unidentified persons are available and must be ruled out. Identification requires a list of the possible persons involved so that appropriate ante mortem records can be located. The availability and accuracy of these records determine the success of identification. Unfortunately, dentists often maintain poor records, resulting in confusion that makes dental identification impossible.

Structure and Development of Teeth

The human adult dentition typically consist of 32 teeth, each with 5 surfaces, thus providing 160 possibilities for individual variations of surface anatomy and dental restorations in configuration, size, shape, material, and wear patterns. This does not even take in to account, and is not limited to, such factors as decay, missing and extra teeth, alignment of the dental arches, individuals tooth positioning, and prosthetic appliances. Among other distinctive characteristics for antemortem and postmortem comparisons are maxillary sinus patterns, bone trabecular patterns, and orbital outlines. A question often arises as to the number of points of concordance necessary to render a valid decision on a dental identification. However this is not as significant as the singular quality, or exclusivity, of the points of comparison involved. In addition, when all of the points of concordance in a particular case are considered as a set of aggregate data, the investigator should be able to state, if possible, whether the identification is “positive within reasonable scientific certainty.”

The following categories and terminology for body identification are suggested for use in communicating the results of forensic odontology identification investigation:

1. Positive identification: The antemortem and postmortem data match in sufficient detail to establish that they are from the same individual. In addition, there are no irreconcilable discrepancies
2. Possible identification: Commonalities exist among the comparable items in the ante mortem and postmortem databases, but enough information is missing from either source to prevent the establishment of a positive identification.
3. Insufficient identification: The available information is insufficient to form the basis for a conclusion.
4. Exclusion: Unexplainable discrepancies exist among comparable items in the ante mortem and postmortem databases. The antemortem and postmortem data are clearly inconsistent.

In all these cases, the discrepancies can be explained and identification can still be made.

Forensic Dentists area of Practice

1.   Identification of found human remains and Dental profiling

The forensic dentist can often produce a “Picture” of the general features of the Individual. This process is known as post-mortem Dental profiling.

–  Comparative Identification

Post mortem dental remains are compared with ante mortem Dental records including written notes study Casts Radiograph to conform Identity.

–  Post mortem Dental Profile

Provide information on deceased age Ancestral background, Sex and socio-economic status, Dietary habits, Dental and Systemic disease etc.

–  Biological Method

In unidentified individual comparison of DNA in preserved and extracted teeth given better result as compared to hair brush biopsy, stored blood called Ante mortem sample

2.   Sex and Race

The bones and teeth of the craniofacial complex, key identification tools for the forensic odontologist, effectively distinguish one person from others and one population from another and are used to determine the race, age and sex of a person. This anatomic material can be used for identification when the skull and facial bones are used as a foundation for the reconstruction of facial soft tissues. With the use of standard anthropologic thickness measurements at specific points on the face, soft-tissue thickness points can be connected with sculpting clay and the reconstructed features can sometimes be digitized on a computer screen. Because computers permit the addition of components directly to cranial features, computers have been useful for techniques involving facial superimposition. The underlying skeletal structures can thus be viewed below the soft tissue, providing a means to check its accuracy. The result of these techniques is a recreation of the contour of the soft-tissue features that permits visual identification. Various versions can then be stored and reproduced for comparison.

3. Age estimation of both the living and Deceased

Age determination based on Dental Data Age estimation is a sub discipline of the forensic sciences and should be an important part of the identification process, especially when information relating to the deceased is unavailable. Small variations in tooth formation and eruption among persons have made dental estimation of chronological age the primary method of age determination for younger persons. The use of radiographs is characteristic of techniques that involve observation of the morphologically distinct stages of mineralization. Such determinations are also based on the degree of formation of root and crown structures, the stage of eruption, and the intermixture of primary and adult dentitions

4.   Recognition and Analysis of Bite Marks Found on Victims

Another area that utilizes identifying characteristics of the teeth, although on a more functional level, is bite mark analysis. Bites on human tissue may be observed in violent incidents where the attacker may bite the victim or the victim may bite the attacker during defensive responses. Bite mark comparison is fairly new, police investigators have always noticed that at some crime scenes, criminals seem to leave their bite impressions on food products, chewing gum, or more commonly on the skin of their victims, in case of rape, child abuse, and homicide.

Evidence Comparison of bite marks represents dentistry’s vital contribution to forensic science. The bite-mark pattern is compared with the dental characteristics of the dentition o f a suspect. Depending upon the circumstances, a bite-mark pattern may be deposited within foodstuffs, other objects or upon the victim of an assault or homicide. Bite-mark evidence inflicted by a deceased victim may also be seen on a living assailant. For children, in cases other than those of domestic violence, or physical or sexual abuse, biting can represent a form of expression that occurs when verbal communication fails. Biting injuries can result from playground altercations or sports competition.

From the evidence, the forensic odontologist has to first determine whether the pattern is truly the result of biting. Once he or she has established that the pattern is related to the teeth and was not made by a tool, instrument or piece of clothing, and does not represent any kind of cutaneous lesion, infection or injury, the pattern can be compared with the suspect’s dentition for inclusionary or exclusionary purposes. For evaluation of a pattern mark, its characteristics must be recognizable and distinguishable. The shape of the dentition, the teeth and specific anatomical characteristics can create a representative pattern. To accomplish these goals, the forensic odontologist can use numerous methods. Because there is no single method for the analysis of bite-mark evidence, the particular method used would depend on the circumstances of each case and on the preference and ability of the analyst.

5.   Assessment of cases of Abuse / Analysis of dental malpractice claim

Forensic odontology has an important role in the recognition of abuse among persons of all ages. Another area in which the forensic odontologist is being consulted more frequent is in case of alleged human abuse, especially in the case of children. Family members, friends of the family, siblings, paramours, and caregivers are most often high on the suspect list in child abuse bite marks and patterned injuries. The dentist should be aware of child, elderly or spousal abuse when confronted with unusual oral injuries, especially in cases of persons with accompanying head or body injuries. Although child abuse or abuse inflicted on people of any other age is not a frequent area of concern to the dentist, as a provider of primary health care he or she is required by law to report such instances to the proper authorities. Unfortunately, the incidence of dentists’ reports is low.

Major reasons preventing dental professionals from getting involved in cases of abuse include ignorance about maltreatment, lack of awareness of legal mandates to report it, fear of dealing with an angry parent, reluctance to believe parents (or others) could be abusive or neglectful, and fear of losing patience and therefore income. The primary role of a dentist intervening in any form of violence is to interrupt the violence, not to attempt to resolve individual conflicts or provide counselling to abuse victims. Simply recognizing the signs of abuse, privately discussing these concerns with the patient and knowing where to refer abuse victims are appropriate goals for a dentist confronted with violence.

6.   Genetics / Source of DNA

Tooth an important source of DNA in Forensic odontology. DNA is a genetic blue print that makes living being.

Importance of Dental DNA testing

• Crime solving – matching suspect with evidence
• Accidents Victims – after Airplane crash
• Soldiers in war – who is the Unknown Soldier
• Paternity testing – who is the Father
• Immigration testing – are two people related
• Missing person investigation – whose remains
• Convicted felons databases cases solved

Each practitioner has a responsibility to understand the forensic implications associated with the practice of his or her profession. Appreciation of the forensic field should give the dental clinician another reason to maintain legible and legally acceptable records, and assist legal authorities in the identification of victims and suspects.

Mass Causality Incidents

Mass Disaster Identification Transport accidents form the majority of cases in which dental identifications are needed, particularly aircraft accidents in which both fire and trauma are often severe. Fires in and collapse of heavily occupied buildings are another source of multiple problems of identification.  The  forensic  odontologist  is  usually  a  member  of  the  investigating  team,  the composition of which varies, depending on the nature of the disaster. Generally, the team includes a coordinator or head of the team, a pathologist and various specialists with experience related to the particular type of disaster, in addition to the forensic odontologist. In a situation involving fire or severe trauma, physical features are often destroyed. Because teeth are heavily calcified, they can resist fire as well as a great majority of traumas. Dental examination is significantly confounded when heat and flames have fragmented tooth enamel, and soot and smoke have been deposited on the teeth. Generally, teeth and restorations are resistant to heat, unless they are exposed directly to flame. Preservation is possible in most cases.

Analysis of Dental Evidence

Many unique characteristics and variations exist “labelling” the type, quality, and socioeconomic levels of the dental restorations performed both currently and in the past. These factors and analyse can be helpful in a forensic investigation, both in opening avenues of exploration and for court expert testimony. In a number of cases the findings of a single tooth or fragment of a tooth has been a pivotal point in assisting in an investigation

Radiographic Examination

Comparison of ante mortem and postmortem radiographs is the most accurate and reliable method of identifying remains. Observations such as distinctive shapes of restoration, root canal treatment, buried root tips, bases under restorations, tooth and root morphology, and sinus and jawbone patterns can be identified only by examination of radiographs. In some instances a single tooth may be all that remains, and upon comparison of radiographs, a positive identification can be made. Original ante mortem dental radiographs are of immense value for comparison; therefore it is essential that all routine radiographs exposed during the course of a dental practice be adequately fixed and washed so that they remain viewable years later. The best results are obtained when the angulat ions of the film to the x-ray tube is the same as that of the original films. Identification becomes a problem when few restorations are available for antemortem–postmortem comparison.

Today, fewer people have dental restorations because of the success of preventative intervention. However, at some stages of the development of human dentition, digital dental radiographic superimposition can be used for identification, allowing comparison of the spatial relationships of the root and support structures of the teeth in antemortem and postmortem records. When an antemortem record is unavailable, the postmortem chart of the deceased may be used to exclude his or her identity upon comparison with the available antemortem records of others.

Developmental applications

The field of forensic odontology continues to advance as a science. The computer is being used more and more in many aspects, from assistance in identification matching, to enhancement of x – ray films and bite mark evidence photographs. The scanning electron microscope is being used to amplify details of individual components of bite mark evidence. Alternative light sources such as UV range, infrared, etc., can be help full in the visualization of suspected healed skin injuries. These light sources, in various wavelength , can penetrate the skin surface, or filter out overlying debris, in order to better document bite or patterned skin mark evidence photographically.

Dental record as a legal document

The forensic odontologist assists legal authorities by examining dental evidence in different situations. The dental record is a legal document owned by the dentist, and contains subjective and objective information about the patient. Results of the physical examination of the dentition and supporting oral and surrounding structures must be recorded. In addition, the results of clinical laboratory tests, study casts, photographs and radiographs become components of the record, and should be kept for 7 to 10 years. All entries should be signed or initialled by recording personnel. Changes in the record should not be erased, but corrected with a single line drawn through the incorrect material. This method permits the original entry to remain readable and removes any questions about fraudulent intent to alter recorded information. Computer-generated dental records are becoming more common for dental records. The obvious advantage of the electronic record is that it can be easily networked and transferred for routine professional consultation or forensic cases requiring dental records for identification. However, the use of electronically managed dental records creates an ethical issue about the maintenance of patients’ privacy. Additionally, potential for insurance fraud is associated with the computer enhancement of dental lesions or restorations on electronically generated dental radiographs. Whether dental records are preserved in written form or on a computer database, following the principles of record management ensures that all dental information that may be required to resolve a forensic problem is properly maintained and retrievable.

Presenting Evidence in Court as an Expert Witness

Forensic dentists are either called by medical examiners or police investigators. There is a movement underway to set up an emergency call – out procedure in many jurisdictions. An expert witness is an expert who makes this knowledge and experience available to a court (or other judicial or quasi- judicial bodies. Reporting an instance of human abuse to the proper authorities is mandatory in most jurisdictions. The dentist must also understand that his or her testimony may be needed for future legal proceedings. If oral injury is involved, the dentist should maintain complete and precise records of the findings for scrutiny by legal authorities. Necessary radiographic studies should be retained as a part of the record. Photographs of the injury or injuries are often helpful to document injuries. Forensic odontology involves the management, examination, evaluation and presentation of dental evidence in criminal or civil proceedings, all in the interest of justice. Investigator experience, knowledge of testing methodologies, and decision analysis abilities, among other issues, all contribute to successful evidence evaluation and assessment.

SUMMARY

Forensic odontology (dentistry) is an important area often performed along with anthropology. Forensic odontology which will not only benefit medical fraternity and scientific minds but will also go a long way in helping police in their investigate work. As a result, aside from fingerprint analysis, one of the most legally reliable forms of identification of human remains is by comparison of dental structures with dental records. Forensic odontology help with the identification of human remains, estimate age, analyze bite marks, and help determine whether abuse has taken place. The identification of dental remains is of primary importance when the deceased person is skeletonised, decomposed, burned or dismembered. Forensic dental fieldwork requires an interdisciplinary knowledge of dental science. Dentistry has much to offer law enforcement in the detection and solution of crime or in civil proceedings. Anthropologic Examination in addition to analysis of teeth, the most common methods of identification include visual identification, fingerprinting, serologic and DNA comparison, and anthropologic examination of bone. Each method has its advantages and disadvantages. They all rely on the principle that identification is derived from a positive correlation between known information about a person and findings from a physical examination of the decedent. Forensic anthropologists and forensic odontologist may work together to resolve problems associated with identification. Both disciplines are concerned with the analysis of calcified structures of the body, namely the bones and the teeth.