Forensic Dentistry
Identification and Methods Utilized

Dental records are used to aid in the identification of individuals who are victims of criminal acts, murder investigations, mass fatalities or missing persons.¹ The confirmation of a decedent’s identity is important for several reasons (Table 1). One of the most important is bringing closure to the immediate family members when tragic or unexpected events occur.⁴ Another reason is for legal settlements of estates where a death certificate is needed.⁴ In order for a death certificate to be issued, a confirmation of identity is needed.⁴ This is why dental identification assumes a primary role in the identification of remains when postmortem changes occur, traumatic tissue injury occurs or there is a lack of fingerprint records which invalidates the use of visual or fingerprinted evidence.¹ Identification is crucial when the deceased is decomposed, burned, dismembered, or skeletonized.¹

The evidence that can be derived from teeth is the age estimation (i.e., children, adolescents, adults) and identification of the person to whom the teeth belong. This is done using ante-mortem (prior to death) dental records, radiographs¹³ and photographs and by comparing them to post-mortem records. It is important for dental professionals to document information in the ante-mortem dental record clearly, correctly, and specifically. Forensic dentistry starts with dental professionals and so, dental professionals are encouraged when documenting to utilize universal abbreviations when needed, and to be detailed about the procedures conducted on patients. A person’s teeth change throughout life and the combination of decayed, missing and filled teeth is measurable and comparable at any fixed point in time. Therefore, quality radiographs and accurate charting are the FIRST steps in providing a positive identification.

Teeth have the ability to survive decomposition and withstand extreme temperature changes, which is why dental evidence comparison is one of the most dependable and reliable methods of identification.⁴ This is made possible by comparing features of an unknown individual (post-mortem dental records) with a known individual (ante-mortem dental records). For this reason, it is extremely important an accurate and detailed evaluation of the unknown individual is documented to provide the best possibility of successful comparison with ante-mortem records.⁴ The following is collected for post-mortem documentation: photographs (digital or film based) which provide the ability to view specific features without having to review the body, radiographs (full mouth series) (Figure 1), and a complete dental record for post-mortem and ante-mortem paperwork (Figures 2A & 2B).¹⁷ The primary goal of post-mortem dental records is to locate, identify and document anatomical structures, dental restorations and dental appliances that will assist in the comparison process.⁴ The more information documented from the post-mortem examination, the better the possibility for successful comparison.⁴

There are three categories examined when comparing dental records (ante-mortem with post-mortem) for identification, which are the teeth, periodontal tissue, and anatomical features.¹³ When conducting a comparison regarding teeth, it is important to determine if they are present (erupted, unerupted, impacted), congenitally missing or lost ante-mortem/post-mortem, tooth type (permanent, deciduous, mixed, retained primary, supernumerary), what the tooth positions are, crown morphology and pathology, and root morphology. Pulp chamber and root morphology may also be considered valuable information in identification. The pulp chamber can be used to distinguish approximate age of the individual, since the chamber size varies from children to adult teeth. The root morphology along with the pulp chambers will assist in determining whether the tooth is from the maxillary or mandibular arch, and distinguishing if it is an anterior or posterior tooth.¹⁴ Incidents such as plane crashes and explosions can damage the coronal surface of the tooth. A positive identification is still possible by comparing the pulp chamber and root morphology.¹² The root surfaces of teeth have unique shapes and bends that just may be the key to a positive identification.

Other factors to look for when conducting a comparison are the periodontal tissues in regards to gingival morphology and pathology, periodontal ligament morphology and pathology, and the alveolar process and lamina dura. In addition to anatomical structures such as the maxillary sinus, anterior nasal spine, mandibular canal, coronoid condylar processes, temporomandibular joint (TMJ), and other pathologies (developmental cysts, salivary gland pathology, trauma, evidence of surgery, metabolic bone disease, reactive/neoplastic, focal or diffuse radiopacities).^14,15

There are computer identification databases such as WinID^© or NCIC that are used today to compare ante-mortem and post-mortem data in the identification of deceased or missing individuals. WinID^© is a dental computer system that matches missing persons to unidentified human remains. WinID^© makes use of dental and anthropometric characteristics to rank possible matches.¹⁷ WinID^© is used by forensic dentists, forensic odontologists, pathologists, coroners, medical examiners, forensic anthropologists and those in the law enforcement and criminal justice systems to identify the unknown.¹⁷ DMORT, which is a federal response team, includes dental team members that are deployed to aid in identifying victims.¹⁸ These teams are currently utilizing WinID^© for identification(s) as well as a digital imaging software just for forensic identification that can interact with WinID^© entitled DEXIS Forensic (Figure 3).¹⁷ DEXIS Forensic has a computerized receiver that is inserted into a laptop computer. The system utilizes charge coupled device (CCD) sensors that are placed in the victim and exposed to radiation providing an instant radiographic image on the computer screen. In addition, DEXIS Forensic has the capability to scan existing film-based dental records into WinID^© for electronic transfer and comparison. This capability is utilized for inputting ante-mortem records into WinID^©. WinID^© was used for the first time to assist in the identification of Hurricane Katrina victims in the American Southeast in 2005.¹⁸

The Federal Bureau of Investigation also has a computer database called National Crime Information Center (NCIC) through the Criminal Justice Information Services (CJIS) Division.^4,19 The purpose for maintaining the NCIC system is to provide a computerized database for ready access by a criminal justice agency making an inquiry and for prompt disclosure of information in the system from other criminal justice agencies about missing or unidentified persons, crimes and criminals.^4,19 This information assists authorized agencies in criminal justice and related law enforcement objectives such as apprehending fugitives, locating missing persons, locating and returning stolen property, as well as in the protection of the law enforcement officers encountering the individuals described in the system.^4,19

The National Institute of Justice in 2007 began funding the National Missing and Unidentified Person Systems (NamUs).⁴ The NamUs system has two databases, one for unidentified decedents and the other for known missing persons data. In 2009, the NamUs system established a link between the two databases that allowed the comparison of unidentified remains to known missing persons.⁴ The database is searchable and accessible by medical examiners, forensic scientists, law enforcement, and the general public.⁴