Scope of Forensics in Dentistry
The scope of forensics in dentistry (also called forensics in odontology) includes both the identification of human remains and the associated legal responsibilities. Dental forensics may involve the identification of an individual or in some cases multiple individuals, such as from a mass disaster. In the latter case, the task would be preferably handled by a team that includes forensic odontologists, a forensic anthropologist, and a forensic pathologist for biologic profiling or population stratification.
Stratification is the sorting of multiple individuals based on age and, to a lesser extent, race and gender. When this process is applied to a group of unidentified human remains, it enhances the chance to make a positive match between one individual and the dental records of missing persons. If a match is impossible, at least the assessment of the developmental age of the dentition of individuals using diagnostic imaging allows the forensic dentist to determine the age. This determination involves a process where the developmental age of the dentition of an individual is compared with the mean developmental ages of a standard population to arrive at a chronologic age. This process also can be performed on living individuals, such as when identifying individuals with amnesia. There are other methods (not included in this chapter) besides the developmental age of teeth to determine chronologic age, such as determining the developmental age of the bones of the wrist and hand. Virtually all age determinations by any scientific process have an associated error rate. According to Saks in his publication, “The Coming Paradigm Shift in Forensic Identification Science,” quantification of error rates in the comparative forensic sciences has been problematic. For this reason, it is imperative that the forensic dentist understands the inherent scientific errors and is cautious in selecting language used to state opinions in official reports.
Forensic dentists also contribute to cases involving bite-mark injuries including recognition, documentation, and analysis of injuries. Analysis involves comparison of a known dentition with a bite mark in a substance, including human skin. Such cases may involve civil litigation or providing aid to dental regulatory authorities. Radiology often provides objective data that are useful in supporting the opinions of a forensic dentist. This chapter focuses primarily on the role of the forensic dentist in identifying human remains.
Need for Identification of Human Remains
Human remains are identified for personal, legal, and societal reasons. People place great importance on verification of the identity of the deceased from a personal perspective because doing so gives a measure of closure to loved ones, permits appropriate funerary rites, and allows appropriate religious ceremonies to be undertaken. In the absence of knowing for certain that a loved one has died, the grieving process may be delayed or interrupted.
From a legal perspective, certification of death is required before payment of life insurance; settling of wills and estates; dissolution of business partnerships, contracts, and marriage; and settling of debts. Just as important from a legal perspective is the commencement of suspicious death investigation. Knowing the identity of a person who died under suspicious circumstances may instigate the investigation. Also, fulfilling the legal requirements for the identification of an individual has importance for society as a whole. A competent forensic death investigation of human remains has four goals: determination of the means, manner, and cause of death and identification of the remains.
Methods of Body Identification
The primary methods used in body identification are visual identification, fingerprint identification, DNA identification, identification by the presence of unique skeletal or medical devices, and dental identification. Visual identification, although the most common method, is unpleasant and may be unreliable. This method can be considered a form of comparative science practiced by someone without scientific training and at a time of high stress and in difficult circumstances. Errors in visual identification are well documented. Fingerprint identification is common but requires that the deceased individual has fingerprint records before death (e.g., criminal record, military or police service) and for the cadaveric fingerprints to remain intact after death. The fingerprints may not be intact in cases where the body has undergone decomposition, maceration, or incineration. Fingerprint identification is impossible with skeletonized remains.
DNA identification, accomplished by comparing an antemortem (before death) sample with an unknown set of human remains, provides confident identification except between identical twins who have the same DNA. In addition to comparative identification, DNA analysis can be used for racial stratification where a DNA trait may indicate the ethnocultural group of a deceased individual.
Identification by skeletal or medical devices can be made if these devices have serial numbers or if they are unusual in form (Fig. 34-1). Additionally, frontal sinus morphology is quite variable, and this region may be used to compare antemortem and postmortem (after death) diagnostic images for the purpose of identification.
Dental identification has many advantages over the other techniques. Empirical testing has proven that it is reliable, straightforward when antemortem images are available, and readily demonstrable in courts of law. It is also quick and inexpensive.
Utility of Dental Radiology for Body Identification
Diagnostic images are used in dental identification because they provide objective evidence of the antemortem and postmortem condition. Conventional radiographs and digital images are a permanent record of the antemortem condition at the time they were exposed and are difficult to misinterpret. In contrast, a dental charting by one dentist may not be directly comparable to a dental charting by a second dentist of the same patient. Despite the forensic utility of antemortem dental images, most dentists (appropriately) do not expose a full-mouth set of images at each appointment. As a consequence, antemortem images should be analyzed in conjunction with the antemortem dental chart. Antemortem dental images should never be exposed for the purpose of providing a record for later comparison, even in high-risk groups such as convicted criminals or sex-trade workers. Use of the chart and antemortem images of known date allows the forensic dentist to produce an antemortem odontogram, a record of the patient’s dentition, which can be compared with the postmortem conditions for the purposes of identification.
Identification of a Single Body
The process of body identification using dental criteria is relatively straightforward and is outlined in the American Society of Forensic Odontology manual. Using diagnostic images, the forensic dentist identifies points of agreement (concordance) between the antemortem and postmortem images and lists them numerically. There is no set number of points needed for an identification to be made. A decedent who was edentulous before death may/>