Forensic Odontology

• Author: David Sweet O.C.
• Pages: 576-625

576

A. OVERVIEW OF THE DISCIPLINE: FORENSIC ODONTOLOGY

On a damp, dark evening in mid-October, a young woman was grabbed as she

left a bar and was walking to her car. After the unknown man forced her to drive

to the edge of the city, he dragged her from the car and assaulted her. Later, she

could not be visually identif‌ied because of the beating. However, the police needed

to identify her before they could start to piece the bits of evidence together. Once

it was determined who she was, they could then focus on the teeth impressions

the murderer left behind.

Cases of sexual homicide similar to the one described above are dif‌f‌icult

to solve and raise many questions. Who do the police call to help them

jump-start the investigation? Who is it that can assist investigators to

identify the victim so the search can begin for where she was last seen,

whose company she was in, what circumstances led to her disappear-

ance, and much more? Who can potentially identify the perpetrator by

analyzing the bitemark left on her body? The forensic odontologist is the

expert that the police call for specialized help to answer these crucial

questions.

Forensic odontology (dentistry) is the area of intersection and overlap

between the dental and legal professions. The discipline involves proper

recognition, collection, examination, and evaluation of dental evidence on

behalf of a legal authority. Dental evidence may be found in the teeth and

various oro-facial structures, including the tissues and bones of the face

CHAPTER 17

Forensic Odontology

David Sweet O.C.

LEgAL ConTExT: CAiTLin PAkosH

Forensic Odontology 6 577

(used for age estimation and person identif‌ication) or in the impressions

and marks left by teeth on relatively soft substrates (used for bite-mark

investigation).

There are two ways that forensic dental evidence can be applied to

criminal cases: (1) the identif‌ication of living or deceased persons using

the characteristics of their teeth and jaws compared to pre-existing dental

or medical records, and (2) the linkage of one person to another or of a

person to a place through the identif‌ication and comparison of atypical

physical features of the teeth to subsequent impressions or marks from

the same teeth. Conversely, forensic dental evidence can operate for ex-

clusionary purposes.

Historically, interest in forensic dentistry in North America increased

when the f‌irst formal instructional program was presented at the Armed

Forces Institute of Pathology in Bethesda, Maryland, in the 1960s. Since

then, many formal courses have been presented in Canada and the United

States, and several organizations have been established to foster the edu-

cation and development of dentists with an interest in providing expertise

to the civil and criminal bar.1 The number of cases reported has continued

to increase to a point in Canada where assistance is readily available for

cases involving dental evidence.2

B. PERSON IDENTIFICATION

Conclusions from forensic dentists after comparing the post-mortem den-

tal records of a deceased victim and the antemortem dental records of a

missing person can answer important questions at trial. Answering, “Who

was it that died?” is obviously an important legal question in a homicide

trial. In countries like Canada, where accurate, precise, and readily avail-

able dental records exist, the identif‌ication of the deceased victim can be

accomplished in an ef‌f‌icient, inexpensive, and expeditious way compared to

other identif‌ication methods. Community-based forensic dentists consult

with coroners, medical examiners, and police agencies with jurisdiction

in any given case to employ dental records for these purposes. Identif‌i-

cation of deceased persons in Canada is a coroner or medical examiner’s

responsibility depending on the region within the country, and police

1 L. Luntz, “History of Forensic Dentistry” (1977) 21 The Dental Clinics of North Amer-

ica 7 at 13–14.

2 S.L. Kogon, “Dental Evidence” in Gary M. Chayko & Edward D. Gulliver, eds., Fore n-

sic Evidence in Canada, 2d ed. (Aurora, ON: Canada Law Book, 1999) 361.

578 6 David Sweet O.C.

investigations often occur in parallel. Dental identif‌ication conclusions

have been shown to be sound, scientif‌ically based, and reliable; however,

personal interpretation of changes in a person’s dental status over time

by dentists of varying experience and the fact that there is no method to

measure the uniqueness of the traits that forensic dentists consistently

rely on are inherent problems.

1) The Science of Forensic Odontology: Person Identif‌ication

Given various ambient conditions, such as heat, moisture, ultraviolet light,

and animal predation, the human body will decay, decompose, and dis-

integrate after death. Teeth can survive these conditions well and thus

can provide important evidence. In Canada, dental traits allow ef‌fective

identif‌ication of a person because of the availability of high-quality den-

tal records from the person’s dentist. Clinical dentists store a record of

natural plus acquired traits of a person’s teeth and authorities can seize

these records when the person goes missing. Forensic dentists can com-

plete comparisons of these records to similar traits in a found body. If the

natural and other traits acquired through previous treatments are deter-

mined to be the same and no unexplainable discrepancies exist, the body

can be identif‌ied as the missing person from whom the dental records are

obtained.3

This comparison of before- and after-death dental records is referred

to as comparative dental identif‌ication. It is dif‌ferent than reconstructive

identif‌ication, in which the odontologist attempts to prof‌ile the deceased

person (e.g., estimate age at death, ethnicity, socio-economic status). These

estimates are subjective opinions that are based on the dentist’s know-

ledge and previous dealings with large numbers of patients from various

ages and populations.4

Only original dental records should be seized from a dentist’s of‌f‌ice for

identif‌ication purposes. Copies of various records are very problematic.

For example, duplicated f‌ilm-based radiographs have no left-right lateral-

ity markers, and the colours present on written dental charts that depict

cavities and various traits or treatments are lost in black-and-white photo-

copies. Most practising clinicians believe that their original records should

3 I.A. Pretty & D. Sweet, “A Look at Forensic Dentistry—Part 1: The Role of Teeth in

the Determination of Human Identity” (2001) 190 British Dental Journal 359.

4 Ibid.