At least 24 men convicted or charged with murder or rape based on bite marks on the flesh of victims have been exonerated since 2000, many after spending more than a decade in prison. Now a judge's ruling later this month in New York could help end the practice for good. A small, mostly ungoverned group of dentists carry out bite mark analysis and their findings are often key evidence in prosecutions, even though there is no scientific proof that teeth can be matched definitively to a bite into human skin. DNA has outstripped the usefulness of bite mark analysis in many cases: The FBI doesn't use it and the American Dental Association does not recognize it.
Two court cases this month are helping to bring the debate over the issue to a head. One involves a 63-year-old California man who is serving a life term for killing his wife, even though the forensic dentist who testified against him has reversed his opinion. In the second, a New York City judge overseeing a murder case is expected to decide whether bite mark analysis can be admitted as evidence—a ruling critics say could kick it out of courtrooms for good. "Bite mark evidence is the poster child of unreliable forensic science," says the director of the Innocence Project, which helps wrongfully convicted inmates win freedom through DNA testing. "It's very inflammatory. What could be more grotesque than biting someone amid a murder or a rape hard enough to leave an injury? It's highly prejudicial, and its probative value is completely unknown." (Read more bite marks stories.)