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The inane responses of dentists who describe themselves as “skin-reading” experts

This is a guest post by Dr. Michael Bowers

The non-scientific dental discipline known as bitemark analysis has only a few dogmatists left, who deny its well-known status as a forensic train wreck and cling to decades old assumptions that judicial admission of their baseless opinions is a substitute for validation and reliability proofs. The downward slide of forensic dentists who tout themselves as “readers” of skin injuries caused by human teeth has been occurring for the last ten years through criticism from legal academics (Saks 1999, Gianelli 2009, Beecher-Monas 2009, Deitch, 2010; and a small cadre of sagacious forensic dentists; Rothwell 1999; Sweet, Pretty 2001, Pretty 2010; Clements 2010. This slip from glory has also been assisted by a string (N>12) of DNA fueled exonerations overturning erroneous convictions originally helped by the opinions of highly credentialed members of the American Board of Forensic Odontology. Finally, within the last four years, bitemark experts have been challenged as bitemark “readers” by the independent and compelling research from the University of Buffalo (mentioned here in previous blogs on bitemarks.org) denoting human skin’s inability to accurately record tooth marks and questioning the uniqueness of the human front teeth. Taken together, the undeniable exonerations and current research results point to the fact that serious questions must be raised about the astonishing opinions that are being made concerning the very poor pattern impression evidence that constitutes bitemark evidence.

In response to the above, the forensic double-speak currently in vogue by the ABFO and its sub group of bitemark devotees is worthy of description. Just think of the analogy of Copernicus versus Galileo. The flatlanders (ABFO) have historically engaged, both in writing and declaration, that more research has been needed regarding their assumptions that human teeth are like fingerprints and bitemarks can be accurately measured and interpreted. As expected, the 2009 NAS Report made these two “commandments” the core of their blast-off on bitemarks and opined that they “might” be validated by proper research. The proper research has arrived.

Unknown (I am assuming) by the NAS when their committee met with Dr. David Senn in April 2007 as the single bitemark proponent to speak before this group, relevant research at the U of Buffalo had already been initiated. If Senn had been aware of it, I am sure he would have praised it to the NAS as examples of dentistry’s forward thinking commitment to scientific truth. He didn’t, however bring it up. He spoke eloquently regarding the challenges to bitemark identification. So well, in fact, the NAS adopted, in toto and verbatim, his text and republished it as their findings. The rub for the ABFO today is that the Buffalo research has addressed the issues identified in Dr. Senn’s testimony to the NAS committee and it is game over for the “skin readers” as a stand alone forensic tool. DNA from saliva from a bitemark is the optimum method for criminal justice.

What Senn has done since the 2009 Report is to claim in his (with co-editor Dr. Paul Stimson) 2010 text “Forensic Dentistry” that the NAS was misled by the Galileans whose opinions were cited alongside his in the Report. Such is the slippery slope of post-hoc backtracking away from the NAS by him and those bitemark practitioners criticized by the NAS. Since the NAS results showed it untenable to continue the status quo of the culture of bitemark identifications, the best three choices by Senn were to call the Congressional mandated review committee stupid, biased or ill prepared to render an opinion.

This theme of revisionism (rewriting history) and denial continued within the ABFO as evidenced by a lack of ABFO response to neither the NAS, nor the above stated anti bitemark research until this last February, at the ABFO annual meeting in Chicago. Some speakers presented public views that significant limits on bitemark opinions should be adopted and followed by its members. Kudos for that, but their rules and procedures manual still lack any restrictions in that regard AND the silence or vacuum of proofs on the science behind their courtroom declaration of probabilities of biter identification is deafening.

In Chicago there was a “members only” ABFO meeting with the Buffalo research team (with one invited non ABFO guest allowed at the last minute). Peter Neufeld of Cardozo Law’s Innocence Project and Michael Baden attempted to attend, but were turned away at the door. Its “aim”, according to the ABFO, was to have the Buffalo team present their compilation of 8 peer-reviewed papers on the match rates of human teeth (similarities of dentition within studied population groupings) and the uncontrollable physical variables of skin as an impression material. Their process of investigation was clearly organized and questions from the group were allowed. The only potential for dissension surfaced when there was a demand by Senn (the NAS bitemark presenter) for the team to publish a disclaimer that their findings had little to do with the issue of the actual practice of bitemark identification. The polite answer offered to him was to perform his own research to refute the implications of the Buffalo findings. This was truly an academic piece de resistance.

My final comment on the inanity of these bitemark true believers is the red herring strategy promulgated by a blogger whose glory board can be seen at Dr. Roger Metcalf’s blog. The publication of attack opinions on the veracity and research credentials of the Buffalo team resides on this site. The will to survive in the face of bitemarks’ non probative determination by the US Congress entices desperate people to reveal more about themselves than anyone wants to know.

Whilst a few will opine that bitemarks are valid given certain conditions, what will it take for them to outline and make clear those conditions? How many more exonerations will it take for the ABFO to realize that this fictitious, subjective “skin reading” and comparison to a suspect’s dentition is founded mainly upon the pompous attitude of some dentists claiming expertise based upon experience and supported by their so called scientific methodology? There are many dedicated scientists and dentists who have spent years working to become ABFO board certified. Those who have recognized the current research trends and the limitations of bitemark analysis need to take a stronger stance in reforming the ABFO rules and procedures in order regain credibility in the forensic science and legal communities. It is our obligation to the public we serve to see that these changes are made.

Summary: The “skin readers” in dentistry continue to harass and slander members of the broader and more sophisticated scientific community who are developing a research based foundation for the admissibility or inadmissibility of bitemark opinions in court. The research and actual case analyses over the last ten years have seriously undermined the use of bitemark patterns by prosecutors. The few die-hard dentists who continue to press for its use in criminal investigations are now resorting to personal attacks, misinformation and red herring objections to the peer reviewed articles pointing out the failure of bitemark comparison as a forensic discipline.

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Bitemark Book Review

Forensic Odontology is a fascinating and challenging subject. The explosion of technological and procedural advances coupled with the general publics increased awareness through the media such as “CSI” has made forensic sciences appealing to many and seemingly infallible to others.

I have known Dr. Bowers for over twenty years. We first made acquaintance in Louisville, Kentucky in 1989 while challenging the ABFO dental certification board examination. Over these years he has earned the respect of all others in this field with his determined dedication to further forensic odontology into a respected discipline of the forensic sciences.

The second edition of “Forensic Dental Evidence: An Investigatorʼs Handbook” edited by Dr. C. Michael Bowers is written for those whose desire the knowledge, background and understanding of forensic dentistry. This book is essential reading and a valuable asset for any investigator, lawyer, medical examiner, nurse or dentist that has an interest or a role in a forensic dental case.

A highlight of this handbook is the discussion of the wrongful convictions and erroneous bitemark opinions that have surfaced in the past decade. In the early 1990s Dr. Bowers and others become cautious in the manner in which bitemark opinions were being used to identifying specific individuals in an open population. Currently there have been 10 exonerations of individuals who have served many years in prison that were falsely imprisoned as a result of faulty bitemark evidence and incorrect opinions. These opinions were not based in science and were without validity or reliability. Dr. Bowers asan impartial dental expert and DNA evidence resulted in the exoneration of these innocent individuals.

Dr. Bowers determined work in educating and informing the forensic community of the need for scientifically validated opinions in the 1990s went largely neglected by forensic dentists. In 1999 the ABFO performed a bitemark workshop to examine the ability of the expert to properly discern the biter from a lineup of unknowns. The ABFO published a paper with the results that reported the ability of the forensic dentists to identify the correct perpetrator with moderate accuracy of 86%. What was not reported was the high level of false positives that accompanied these findings. Dr. Bowers high ethical standards compelled him to uncover the actual findings that revealed this high false positive rate that was not exposed in the scientific paper published by the ABFO.

Recognizing that improvements were necessary in the forensic sciences Congress directed the National Academy of Science to study the problem. In 2009 the National Academy published a report called “Strengthening Forensic Science in the UnitedStates: A Path Forward” which was a comprehensive review of all the forensic sciences,including bitemark analysis. The findings from the report were the same as Dr. Bowers had been teaching and writing about for years. It was not until after the report was published did the dental forensic specialty group begin to acknowledge the need for change. Fortunately this process has begun and positive changes are currently being
made. This handbook relates and discusses all the problems identified by the National Academy of Science.

In this book Dr. Bowers has partnered himself with many of the worlds foremost forensic scientists and dental experts. This handbook offers the latest information available to the forensic community and beyond. It will function to advance the profession and allow justice to be served for all.

University of Buffalo Team Impresses ABFO Bitemark Experts with Science

The joint meeting of the American Academy of Forensic Sciences meeting occurred last week in Chicago. The board-certifying group (ABFO) for bitemark analysis invited the forensic dental research team from the University of Buffalo to present their scientific findings to the diplomats of the American Board of Forensic Odontology. This was a much-anticipated show down in the world of bitemark analysis. The battle lines were drawn between the scientists who have published scientific findings in the literature and a group of the old guard bitemark experts that have been operating on self induced hunches resulting in a number of wrongful convictions of innocent persons that have served years in prison before being exonerated.

The reason for the diplomates disdain of the invitation to the Buffalo group is because the University research team has published articles in peer-reviewed journals that scientifically debunk many of the myths that had been proselytized by some ABFO experts over the years. The published scientific papers have come to the attention of prosecuting attorneys and others in criminal enforcement and have thus diminished the bitemark expert’s credibility in and out of court.

Fortunately for the future of bitemark analysis the presentation was well received by the Diplomats. It is the sharing of science that makes a profession evolve into a stronger discipline. In the past the bitemark experts had based their opinions on flawed research, which resulted in bad outcomes that have taken years to correct. The bitemark experts have made a needed step towards respect by the other forensic sciences. Congratulations to the diplomats for extending the invitation to the University of Buffalo research team and to the president of the ABFO, Dr Frank Wright.

Sample papers from the University of Buffalo

Statistical Evidence for the Similarity of the Human Dentition

The Response of Skin to Applied Stress- Investigation of Bitemark Distortion in a Cadaver Model*