Is It Time to Axe Bite-Mark Testimony?

Evidence in Criminal Proceedings

Evidence is the mainstay for timely resolution of criminal proceedings. It provides the agreeable stand on which the court—judge(s) or jury—makes convictions and acquittals. Understandably, evidence admitted for consideration exists in different forms. bite marks forensic evidenceTraditionally, these forms include testimony of witnesses, video and/or image data, and forensic evidence—DNA or bite-mark testimony.

How Bite-Mark Evidence is used

During a trial, it is permissible to call on expert witnesses to testify on whether or not the criminal defendant left the teeth marks or lacerations on the victim in question. The expert witnesses called upon are forensic odontologists. What they do in simple terms is state the degree of semblance between the actual teeth of the criminal defendant to the bite-mark teeth pattern. The odontologists basis his or her decision by comparing the teeth pattern on the victim to a mold of the criminal defendant’s teeth. If a match occurs, then the court will adjudge the criminal defendant to be the source of the teeth marks.

Disparaging Stats

In a fundamental sense, the bite-mark testimony can be beneficial in a court trial. This has fueled the rise of the number of cases where forensic odontologists and their expert assessment of bite marks was largely the fulcrum on which courts made their decisions. Unfortunately, not all of the testimonies in these cases were true. At least 24 wrongful court convictions and indictments were meted out based on bite-mark testimonies later established to be false.

The Call for a Ban on Bite-Mark Testimony

Interestingly, it isn’t only the stats that paint a grim picture of bite-mark testimony. The forensic science community, which should know far more than any group on the topic, is kicking hard against bite-mark testimony, especially in Texas. The Texas Forensic Science Commission carried out an investigation spanning six months to find out whether the method usually used to apply bite-mark testimony met forensic science standards.

Alarmingly, the conclusion was that the method did not meet acceptable standards.

Furthermore, the study revealed the following:

  • That a specific set of teeth may make teeth wound patterns that appear significantly different
  • That as time progresses, the teeth wound patterns change their shape, owing to the malleability of human skin

A more curious revelation was that in one of the tests that the Commission performed, forensic dentists were unable to agree if a human made one of the bites in the first place. In a different study that the American Board of Forensic Odontology published, the researchers stated that some experienced practitioners were not certain that the marks shown them were even bite-marks. The anti-bite-mark movement reached a climax when a dental school professor at the University of Texas Health Science Center presented a testimony to the Texas Commission that shares a shocking find.

According to the UT San Antonio professor, of all the injuries he assesses, 85 to 90 percent of them do not possess the requisite amount of detail to back a positive comparison to the teeth of a criminal defendant. In light of these compelling findings, the Texas Commission recommended a ban on bite-mark testimony that should hold sway until credible research supports a new method that would enable forensic dentists identify bite marks and their source accurately.

Implications of a Ban in the US

Currently, only Texas puts forward a stern stance of an encompassing ban on all bite-mark testimony. However, the call for a ban appears to be the start of a trend expected to grow exponentially in the coming years, as other states begin to doubt the credibility of dental forensic specialists and the degree of importance of bite-mark testimonies. For now though, the role of the Texas Commission is solely advisory—they can only make recommendations.

Nonetheless, this recommendation, especially one from a highly rated body of experts, would be a view increasingly shared by judges throughout the United States. At least until further research can convince otherwise. That said, time may be the only reason preventing a statewide ban on the use of bite-mark testimony from being enforced in Florida.