1.1 Introduction
When the subject of forensic dentistry arises, the first reaction of many people tends to be toward one of two extremes: either very cool or decidedly gross. The public assumption seems to be that forensic dentistry deals with "the dead." This view is not totally inaccurate. Although the majority of dental identification cases do involve the dead, there is much more involved, including cases dealing with the living, in this interesting field of art and science. With training, ongoing continuing education, and experience, the forensic odontologist will find the application of this knowledge to be personally rewarding. If dentists are interested but do not wish to pursue the reas of forensic dentistry that are associated with "wet work," they will find that they can practice "dry fingered" forensic dentistry in their own offices by accurately recording their patient's oral information on an ongoing basis.
Forensic dentistry or forensic odontology involves several areas that will be discussed generally in this chapter and explained in more detail in later chapters. Te general definition of this discipline is that forensic odontology is the combination of the science and art of dentistry and the legal system, a crossroads of dental science and law. Te general topics to be discussed include the sub disciplines of forensic odontology, dental identification, multi plea fatality incident management, bitemarks, abuse, age estimation, and expert testimony in criminal and civil litigation.
1.2 Dental Identification
When considering the many processes that are involved in forensic dentistry, most laypersons are familiar with identification of a deceased individual through the comparison of dental radiographs. Identification by dental means is a fast and reliable method. Dental identification is most often accomplished by comparing postmortem dental radiographs from the unidentified person with ante mortem radiographs of a known individual. This process of dental forensics is often interpreted on currently popular forensic television series by the actor-dentist holding a dental radiograph backlit by the room lights with the film overhead while standing in the elevator lobby. This generally occurs following a brief evaluation of a body in the morgue. But, of course, the actor-dentist is certain that the radiographs he was just handed for evaluation are from the decedent. The positive identification is completed and without further discussion the district attorney's case theory is confirmed and the suspect is incarcerated.
In real forensic cases the process of using dental radiographs and dental charting can be an accurate and efficient method for making a positive identification or exclusion. But, the comparison must be completed in a controlled and methodical manner, with attention to the details of the dental structures and restorations that may be seen in the radiographic comparison. A comparison of an ante mortem radiograph with a body in the morgue occurs only in the virtual reality of television and film world.
In a dental identification, the initial goal of the forensic dentist is to obtain a set of postmortem photographs, radiographs, and accurate dental charting on the unidentified person. This can be a straightforward or difficult process, depending on the condition of the postmortem specimen and the physical resources available to the dentist. Te problems most often involve limited available resources in the morgue setting.
Procuring ante mortem records can also be a challenge. Often, but not always, there will be some information on the unidentified person, a clue to his or her identity. Once a putative identity is known, the process of procuring ante mortem dental records begins. Many dentists are concerned that their original records must remain in their possession and resist the release of their records. Although it is true that the dentist is expected to maintain the original record, this hurdle is easily cleared by discussion with the dentist concerning the necessity to use the record for comparison of a possible patient and the possible consequences of their interference in a medicolegal death investigation. Also, with the current ability to digitize a paper record by using a flatbed scanner or to take digital photographs of a dental chart and analog radiographs by placing them on an x-ray view box, the problem of resistance from a dental office can be reduced or eliminated. Dental records are readily available from any number of dental facilities that could have previously collected dental information on a patient as part of their examination.
Any dental charting of the teeth, financial records for treatment rendered, insurance claim forms, photographs, and radiographs that would be part of a dental examination are important items to collect as part of the antemortem reconstruction. These items could be part of the dental record reated during an examination in a dental or medical facility. These items could be found as part of a dental-medical record in a private dental practice, dental teaching facility, military in-processing facility, hospital-based dental program, dental in-processing examination as part of incarceration, or medical records of an emergency room. An emergency room could potentially have radiographs of the head/neck region that include dental structures that are found on dental radiographs. Te dental radiographs that are most often seen in a dental comparison are dental bitewing x-rays, as these are generally taken during regular dental checkup visits and are the most recent radiographs available. After the postmortem charting and radiography is complete and the antemortem records are procured, the comparison process can begin. Te detailed reconstruction of the dental records and the comparisons that result in positive identifications are rewarding parts of the work. Te forensic odontologist is able to aid in the closure process for a rieving family.
1.3 Multiple Fatality Incident Management
A multiple fatality incident (MFI) develops when the number of fatalities in the incident exceeds the number the medical examiner or coroner's facilities were designed to handle. Te process of collection of dental information on victims in a mass disaster is identical to the processes that are used in the identification of a single fatality. Te major difference in this process is the potential magnitude of the event and the unique set of circumstances that can surround the event. These may include the location, climate, and coverage area of the event, for example, a plane crash in mountainous terrain, a tsunami in a tropical area, the collapse of multistory structures in a major ity, or a hurricane in a coastal area. Each of these incidents has unique issues that must be addressed with regard to recovery, processing, and storage of remains. Each potential MFI will have its unique problems to overcome, but accurately collecting and comparing the data is the common process in all of these situations With each MFI, there will be the need for personnel with different levels of experience to work together to accomplish the common goal of identifying all of the victims of the disaster. Personnel in all areas of the operation should have the ability and desire to be detail oriented, as errors can lead to missed or misidentifications. A mass disaster team should be organized and trained in coordination with the local or state government to allow the most expeditious deployment of a dental team when its services are needed. These areas will be discussed fully.
1.4 Bitemark Evidence Collection and Analysis
Bitemark analysis is the most complex and controversial area of forensic odontology. Consequently, some forensic dentists are reluctant to enter into this arena. Bitemarks can occur in a wide variety of substrates, although the most common of these is, unfortunately, human skin. Te proper documentation of a bitemark is not overly complex, and the techniques for collecting vidence are manageable by most forensic dentists with practice and attention to detail. Te bite site can be evaluated in the third dimension by using a very accurate dental impression material and dental stones or resins to create a solid model for viewing under magnification, light microscopy, or with scanning electron microscopy. This three-dimensional model of the bitten area can then be compared to suspects' dental casts. Technique shortcomings exist and include that solid models of bitemarks on skin are nonrealistic. Te problems associated with bitemark analysis will be discussed more fully.
1.5 Abuse
Identification and reporting of abuse is a complex and emotional area.
Healthcare practitioners are required by law in most jurisdictions to report suspected cases of abuse. Te head and neck area is a common target in abuse. Extraoral injuries consistent in shape and appearance to a hand or object are identifiable. Intraoral trauma can occur as the result of strikes to the face, causing torn frena and fractured, mobile, or avulsed teeth. Intraoral soft tissue pathology may be noted following forced feeding or forced fellatio.
Some cases may require the consideration of whether extensive or rampant caries are a result of the caregivers' lack of knowledge or stem from neglect or abuse. In areas where access to dental care is an issue there will likely be a higher caries incidence that could further exacerbate the determination of whether reporting of abuse may be necessary. Deciding to report suspected buse requires sound judgment, especially considering that the parent or guardian may be the perpetrator. If a report is initiated, the ensuing investigation will be difficult for all concerned.
1.6 Age Estimation
Researchers have studied the processes of human aging by many different methods. These include developmental, histological, biochemical, and anthropological techniques. Anthropologists analyze the fusion of the cranial sutures of the skull, the development of the long bones, features of the pelvic girdle, and along with forensic dentists, features of the teeth. These techniques can be valuable when creating a profile for an unidentified person, whether living or deceased. Estimating an individual's age can also be helpful in assisting law enforcement agencies in determining the attainment of the year of majority of a living individual that will ultimately affect the individual's treatment in the legal system as either a child or an adult.
The methods of age estimation using teeth include analyzing tooth development and eruption, studying tooth degradation, and measuring biochemical and trace element changes in dental structures. Each of these methods has its advantages and limitations in accuracy and in the ease of use. Some can be performed through the analysis of dental or other radiographs or with linical examination; others require laboratory testing or tooth destruction.
The individual jurisdiction's requirements and the odontologist's skill and knowledge will help to establish the appropriate techniques for each case.
1.7 Expert Testimony in Criminal and Civil Litigation
Forensic odontologists are frequently called to give sworn testimony in depositions and courtrooms. Te testimony may involve the previously mentioned areas of dental identification, bitemark analysis, or age estimation. Dentists participating in forensic casework should expect that at some point they will be required to provide sworn testimony.
Forensic dentists also may be called to provide an opinion in standard of care, personal injury, dental fraud, or other civil cases. These cases, as with other forensic cases, require the evaluation of material and the development of an opinion concerning the case. Dental experts are not hired guns, or advocates for one point of view. Dental experts must be advocates for the truth and endeavor to fnd that truth by the application of their special knowledge and skills. The unwavering goal of the forensic dental expert must be impartiality, thoroughness, and accuracy.
1.8 Summary
Forensic dentistry is a multifaceted, interesting, and rewarding blend of dentistry and the law. For most who participate in the field of forensic odontology there is not great financial reward, but the satisfaction of performing difficult and challenging tasks well is immensely rewarding. A forensic odontologist's work can have great impact on the lives of individuals and families.
Their opinions may influence judges and juries in cases that can and have involved exoneration, the loss of liberty, and even the loss of life. This is an awesome and sobering responsibility that should not be casually undertaken.
"The majority of those who fail and come to grief do so through neglecting the apparently insignificant details."
References
1. Allen, J. 1909. Te mastery of destiny, vii. New York: G. P. Putnam's Sons.
