How Forensic Dentistry Works

In January 2007, prisoner Roy Brown, who had been convicted of murder in New York in 1992, was set free. Brown was one of many prisoners who have been released after DNA analysis, not available or widely used during their trial, cleared them of their crimes. In Brown's case, bite-mark analysis was instrumental in his conviction. But DNA from saliva left on the bite matched with a different suspect. So what went wrong?

The bite mark in the Brown case showed six tooth impressions from the front teeth of the upper jaw, although he was missing two teeth at the time. The expert witness claimed that Brown could have moved the skin of the victim around when biting to make it appear that he wasn't missing any teeth. Although this testimony was not the only evidence used by the prosecution, it was instrumental in helping jurors reach a guilty verdict.

Just five years earlier, an Arizona man named Ray Krone was released from prison after 10 years of serving his murder sentence. The prosecution's witness claimed a perfect match between his teeth and a bite mark found on the victim. The witness stated that "a match is 100 percent" Krone was cleared after DNA belonging to another suspect was found on the victim's clothes.

With wrongful conviction exonerations on the rise, experts began studying the reliability of bite-mark analysis. In 2009, the National Academy of Sciences released a shocking report detailing the numerous problems with various forensic science technologies and techniques, including bite-mark analysis. While stating bite marks can sometimes reliably exclude suspects, the report noted no scientific studies supported the assertion that bite marks provide sufficient detail for positive identification.

Several years later, Drs. Iain Pretty and Adam Freeman of the American Board of Forensic Odontology (ABFO) conducted a study among ABFO-certified dentists concerning bite-mark analysis. An overwhelming number of participants couldn't even agree on whether they were looking at an actual bite mark. Freeman subsequently stopped practicing bite-mark analysis.

More recently, after the Texas Court of Appeals released Steven Chaney — a man wrongfully convicted for murder based on bite-mark evidence — the Texas Forensic Science Commission in 2016 called for an end to the practice.

Today, some critics feel that bite-mark analysis should be used only to eliminate, not to identify, a suspect. Others say that it's acceptable to state there is a probability that a suspect created the mark, but that it's important to clarify that bite marks can't be the only thing linking the suspect to the crime. Forensic dentist training as well as proper education of the jury are also factors.

For lots more information about forensic dentistry and crime stuff, check out the articles and links below.

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