Bite-mark analysis can identify a suspect

Bite-mark analysis can identify a suspect
	UNSUPPORTED
	"Forensic dentists can match a bite mark on a victim's skin to a specific person's teeth with a high degree of certainty, providing strong evidence in criminal trials."
Domain	Crime & Public Safety
Tactic	Pseudoscience / Junk Science;
Era	Historical
First seen	1970s
Origin	Courtroom testimony by forensic odontologists in the United States from the 1970s, notably in the 1979 trial of Ted Bundy
Last reviewed	2026-10-27
	Further reading: books on Crime & Public Safety

The claim that bite-mark analysis can identify a suspect was accepted in US courts for decades and helped convict people of murder and rape. Forensic dentists testified that bite marks on victims matched defendants' teeth, sometimes to the exclusion of everyone else. Scientific reviews have since concluded that bite-mark analysis lacks a valid scientific foundation: there is no evidence that dental patterns are unique in ways that transfer reliably to skin, and experts often disagree about whether a mark is even a human bite. DNA evidence has exonerated a number of people convicted largely on bite-mark testimony. Yet the technique has never been fully banned.

The claim

Bite-mark analysts, typically board-certified forensic odontologists, compare photographs or impressions of marks on a victim's body with dental molds of a suspect. They assess features such as the arrangement, spacing and shape of teeth and offer opinions ranging from "excluded" to "consistent with" to, in the past, identifications with "reasonable medical certainty." The claim rests on two assumptions: that each person's dentition is unique, and that skin records this uniqueness accurately.

Origin

Bite-mark evidence gained prominence in the 1970s. In 1979, testimony matching a bite mark to Ted Bundy's distinctive teeth contributed to his conviction for murders at a Florida State University sorority house. The high-profile case helped establish bite-mark analysis in courtrooms. The American Board of Forensic Odontology, founded in 1976, certified practitioners, and courts generally admitted their testimony, often relying on precedent rather than independent scientific validation.

What the evidence shows

National Academy of Sciences, 2009. A landmark report, Strengthening Forensic Science in the United States: A Path Forward, found no scientific studies supporting the claim that bite marks can identify an individual and noted that skin is a poor medium for recording bite marks because it distorts.
Expert disagreement. Studies, including one conducted by the American Board of Forensic Odontology itself, found that board-certified examiners often could not agree on whether an injury was a human bite at all.
PCAST, 2016. The President's Council of Advisors on Science and Technology concluded that bite-mark analysis does not meet scientific standards for foundational validity and is far from meeting them, and advised against devoting significant resources to it.
Texas Forensic Science Commission, 2016. After reviewing cases, the commission recommended a moratorium on the use of bite-mark evidence in Texas courts.
NIST review. A review by the US National Institute of Standards and Technology concluded that the scientific foundations of bite-mark analysis are insufficient to support identification.

Wrongful convictions

DNA testing has exonerated people convicted with the help of bite-mark testimony. Ray Krone was convicted of murder in Arizona in 1992, largely on testimony that a bite mark on the victim matched his teeth; the media called him the "snaggletooth killer." He was sentenced to death, later reduced, and was exonerated by DNA evidence in 2002 after more than ten years in prison. Keith Harward was convicted of rape and murder in Virginia in 1983 based on bite-mark evidence and was exonerated by DNA in 2016 after 33 years in prison. The Innocence Project has documented more than two dozen wrongful convictions or indictments involving bite-mark evidence.

Why it persists

Despite the scientific criticism, some courts continue to admit bite-mark evidence, partly because of legal precedent: once a technique has been accepted in previous cases, judges may admit it without fresh scrutiny. Expert testimony delivered with confidence and professional credentials can be highly persuasive to juries, who may not realize how weak the underlying science is.

Lessons for readers

Professional certification and courtroom acceptance do not prove that a technique is scientifically valid.
Ask whether a forensic method has been tested for accuracy and error rates.
Confident expert testimony can mislead when the underlying evidence is weak.
DNA exonerations have revealed weaknesses in several forensic disciplines.
Precedent can keep unreliable methods in use long after science has rejected them.

Sources

National Research Council, Strengthening Forensic Science in the United States: A Path Forward (National Academies Press, 2009).
President's Council of Advisors on Science and Technology, Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods (2016).
Texas Forensic Science Commission, report on bite-mark comparison (2016).
National Institute of Standards and Technology, Bitemark Analysis: A NIST Scientific Foundation Review (2022–2023).
Innocence Project, case files on Ray Krone and Keith Harward.