Forensic Dentistry

Episode Summary

Executive Summary: The episode explains forensic dentistry, distinguishing the reliable use of dental records to identify deceased people from the highly controversial practice of bite mark analysis. It traces how bite mark evidence entered courts, why it was long treated as science, the major cases and studies that exposed its flaws, and how agencies now increasingly limit it to exclusion rather than identification.

Main Topics: Forensic dentistry as identification science (Priority: 5/5): The hosts explain how teeth and dental records are used to identify bodies after fires, decomposition, or mass-casualty events, emphasizing that this is the widely accepted, noncontroversial side of forensic odontology. Bite mark analysis and its court history (Priority: 5/5): They discuss how bite mark evidence became admissible in 1975 and was then used aggressively in prosecutions, including famous cases like Ted Bundy, helping cement its credibility for decades. Scientific criticism and junk-science concerns (Priority: 5/5): The episode details why bite mark analysis is now widely viewed as unreliable: skin distorts, experts disagree, and the claim that every mouth is unique lacks strong scientific support. Exonerations and wrongful convictions (Priority: 5/5): Examples like Roy Brown, Roy Cohn, John Kunko, and others show how bite mark testimony contributed to convictions later undermined by DNA or recantations, reinforcing concerns about miscarriages of justice. Modern standards and institutional backlash (Priority: 4/5): The hosts note that NIST, the National Academy of Sciences, the Innocence Project, and the American Board of Forensic Odontology have all pushed the field toward a more limited role, generally excluding positive identification. Specialized techniques and historical notes (Priority: 3/5): The conversation covers old and unusual forensic uses of teeth, including plague-era DNA work, age estimation, occupational wear patterns, and Paul Revere’s early dental identification work.

Key Arguments: Dental records are a legitimate forensic tool because teeth survive heat, trauma, decomposition, and other destructive conditions better than most body tissues. Bite mark analysis is far less reliable than dental identification because skin changes shape, bruises, lividity, movement, and healing can distort the mark. The foundational claim that each person’s bite is unique is not sufficiently supported by science and is contradicted by multiple studies showing overlap and disagreement among experts. Even trained forensic odontologists often cannot agree whether a mark is human or animal, or even whether a mark is a bite at all. Several wrongful convictions show the danger of overstating bite mark evidence in court, especially when experts testify to certainty that the science cannot justify. Current best practice is to use bite marks, at most, for exclusion or limited possibility statements, not for positive identification. DNA extracted from tooth pulp can identify ancient and modern remains, including victims of plague and very old human remains.

Data Points: Year bite mark evidence first became admissible in court: 1975 - A murder case involving a bite on a victim’s nose led to appellate approval of bite mark testimony. Ted Bundy murder victims at the Chi Omega house: 4 - Bundy killed four students at Florida State University; bite marks helped support his conviction. Adult human teeth count: 32 - Used to explain standard dental anatomy relevant to records and identification. Tooth growth rate: about 4 micrometers per day - Mentioned as one way age can be estimated from teeth. Human and animal bite-mark expert agreement study: 8 of 100 photographs - In a 2015 study, 39 experts agreed on classification for only 8% of images. Experts in the 2015 bite-mark study: 39 - Board-certified forensic odontologists or members of the accrediting body participated. Dental charts examined in UAE study: 2,000 - A 2013 study found only 51% of charts were unique; the rest matched at least one other. Unique dental charts in UAE study: 51% - Used to challenge the claim that every dental pattern is unique. Non-unique dental charts in UAE study: 49% - These matched at least one other chart, undermining uniqueness claims. Oldest successfully sequenced tooth genome mentioned: 6,000 years old (about 4,000 BCE) - DNA was extracted from tooth pulp in work discussed from 2005. Wrongfully convicted people later cleared by DNA in bite-mark cases: at least 26 - Referenced via the Innocence Project as cases where bite evidence contributed to wrongful convictions. Roy Brown imprisonment duration: almost 20 years (15 years from 1992 to 2007) - He was convicted largely on bite mark analysis before evidence was later recanted. Roy Cohn imprisonment based on bite mark evidence: 10 years - The transcript refers to a conviction heavily influenced by expert bite mark testimony.

Pivotal Quotes: "This is not science. This should not be admitted." — Narrator/hosts discussing the Innocence Project's stance: Summary of modern opposition to bite mark analysis in court. "There is a 100% match between that man's teeth and this bite mark on this murder victim" — Forensic expert testimony described by the hosts: Example of the overstatement that can strongly influence juries. "The furthest you will go is to make three different calls. One, exclude... Not exclude... And then inconclusive." — Hosts describing current ABFO guidance: Describes the modern limit on bite mark conclusions.

Implications: Listeners should trust dental identification but be skeptical of bite-mark certainty in court. Forensic science institutions are narrowing what counts as valid bite evidence, and older convictions based on strong bite-mark claims may deserve scrutiny.