BUFFALO, N.Y. -- 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
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
"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
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.
The authors are one of the first to use a human skin model
rather than animal models or non-elastic biting substrate, such as
wax or Styrofoam. Current human subject restrictions limit
experimentation on living subjects.
"Living bitten tissue may bleed or bruise," explains Miller.
"The initial bitemark indentations rebound shortly after infliction
often leaving a diffuse bruising that may be difficult to measure
accurately. The indentations produced in our study represented the
best conditions for measurement."
The results indicated that when dental alignments were similar,
it was difficult to distinguish which set of teeth made the bites.
Distortion noted in the bitemarks allowed matches even from
different alignment groups. Therefore, the researchers concluded
that bitemarks should be very carefully evaluated in criminal
investigations where perpetrator identity is the focus of a
As Miller notes, "In the past 10 years, the number of court
cases involving bitemark evidence that have been overturned led us
to question the reasons for the erroneous bitemark identification.
It's important to recognize the serious consequences of a
misidentification for the accused, the victim, the families
involved, the justice system and the possibility that the
perpetrator is still at large."
The University at Buffalo is a premier research-intensive public
university, a flagship institution in the State University of New
York system and its largest and most comprehensive campus. The
School of Dental Medicine is one of five schools that constitute
UB's Academic Health Center. UB's more than 28,000 students pursue
their academic interests through more than 300 undergraduate,
graduate and professional degree programs. Founded in 1846, the
University at Buffalo is a member of the Association of American