Against the backdrop of last week's Congressional hearing into the future of forensic science, researchers from the University at Buffalo's Laboratory for Forensic Odontology Research in the School of Dental Medicine, have published a landmark paper on the controversial topic of bitemark analysis.
The Congressional hearing focused on the findings of a National Academy of Sciences (NAS) report on the scientific basis of forensic disciplines. Among the pattern evidence fields (fingerprints, tool marks, etc.) that were reviewed in the NAS report, bitemark analysis received critical commentary. During the hearing, Innocence Project co-founder Peter Neufeld introduced Roy Brown, wrongfully convicted on bitemark evidence and later exonerated through DNA analysis.
In anticipation of the NAS report, the new UB study published in the Journal of Forensic Sciences challenges the commonly held belief that every bitemark can be perpetrator identified.
"Bitemark identification is not as reliable as DNA identification," explains the study's lead author Raymond G. Miller, D.D.S., UB clinical associate professor of oral diagnostic sciences.
"With DNA, the probability of an individual not matching another can be calculated," he says. "In bitemark analysis, there have been few studies that looked at how many people's teeth could have made the bite."
Miller's co-authors include UB's Peter J. Bush; Robert Dorion, D.D.S., DABFO, UB adjunct professor of oral diagnostic sciences; and Mary A. Bush, D.D.S., UB assistant professor of restorative dentistry. Dorion is the editor of the only comprehensive textbook on the subject of bitemarks in forensic science, Bitemark Evidence: A Color Atlas and Text, and is currently the odontology section representative to the board of directors of the American Academy of Forensic Sciences.
The current study investigated three main questions: is it possible to determine biter identity among people with similarly aligned teeth; is it possible to determine how many individuals from a larger sample might also be considered as the biter; and, if there is bite pattern distortion, is it enough to rule out a specific biter while still including a non-biter?
To answer these questions, the researchers gathered 100 stone dental models (replicas of the dentition), which were measured and divided into 10 groups based upon the misalignment patterns of the teeth. After randomly selecting one model from each of the 10 groups, the researchers impressed bitemarks on cadaver skin. After the bitemarks were created, they were then photographed and the indentations were compared to the dentitions using overlays created with photographic software.