The Good and Bad Legacies of Forensic Odontology

ABSTRACT

Modern science is based on the acknowledgment of change and adaptation of beliefs, methods, generated by vigorous periods of discovery. Forensic science and dental science are no exception. Nearly a quarter of the 3,345 of those exonerated in the United States since 1989 were wrongfully convicted based on false or misleading forensic science. This includes bitemark comparison “identification.” This paper is a brief look into how bitemark comparisons contributed to 34 of these miscarriages of justice and, due to compelling research and legal analysis, they have now been debunked via numerous scientific reviewing agencies and legal authorities in the United States (US).

KEYWORDS:

• Bitemarks and wrongful convictions
• bitemark comparison
• forensic dentistry
• junk forensic science
• human dental identification

This paper is a short narrative regarding my experiences being a court-approved forensic odontologist since the middle 1980‘s. Most of this is autobiographical and therefore will not contain myriad citations of bitemark and legal literature. I will leave that to other contributors in this series of articles about forensic dentistry bitemark comparison practices. I will attempt to describe the process I experienced during my formative years and in the following decades listening and communicating with other dentists who were my peers, betters, mentors, many of whom were seasoned witnesses in criminal courts, who were mostly as prosecution-hired experts.

My first exposure to dental identification forensics occurred, ten years prior to my reaching attainment of a “board certification” as a forensic dentist. The introduction was a semester-long course in my freshman year at the University of Southern California. The curricula focused on the forensic career of the presenter who later was a founding member of what now is known as the American Board of Forensic Odontology (ABFO). The program was heavily centered on dental identification of deceased individuals who were victims of crime, accidents and unattended deaths. Each case was an eye-opening experience into the intricacies of dental “science” and application of tried-and-true dental procedures not dissimilar to treating viable patients seen in clinical practice. This didactic experience obtained in the regular dental school later served me as a basis for being admitted as a dental expert both in forensic settings and in civil and criminal Superior Courts around the US. Talking about teeth, restorations, and dental anatomy was deemed a professional skill that courts admitted as special knowledge necessary to answer questions the legal proceedings considered to be relevant to a case before a jury. Statements by an expert are expected to be reliable as determined by the expert’s “scientific community.” Dental identifications seldom result in opposing experts in court proceedings largely because of their close relationship with clinical dentistry and its well developed and published “community.” In stark contrast, the bitemark “community” has been composed of a few dozen adherents in the US.

My forensic activities became even more well grounded when I was appointed as a voluntary Deputy Medical Examiner in Ventura County in 1983. This acceptance led me into the professional world of forensic pathology and dentistry in a medico-legal setting. The doors were opened for me to assist at autopsy, be responsible for forensic evidence relating to investigations, write reports to law enforcement agencies, and eventually become certified by the ABFO. This organization had a requirement that the applicant have exposure and involvement with a single bitemark case. One case was sufficient. By the time I applied to the ABFO, I had five years of forensic dental ID experience, but nothing related to the bitemark requirement. I had listened to lectures and took multiple courses of case studies by dentists who brought their work forward for educational purposes. I found the extant dental literature on the subject was a scatter-shot affair composed of casework. No extensive empirical work existed testing the accuracy of skin as an impression for teeth marks. was the “uniqueness like a fingerprint” assertions that human anterior teeth can reliably individuate patterns to just one biter anywhere to be found. There was an undercurrent of bitemark comparison speculation by two dentists (Furness in 1958 and Whittaker in 1975) stating that bitemark “matching” was unsafe. Sadly, These opinions were ignored by dentists who brought bitemark matching opinions into courts and testified that their bite identification was valid and reliable “beyond a reasonable doubt.” Taking the ABFO certifying exam was difficult in that I had spent 5 years listening to their certitudes that their opines about skin injuries and human teeth passed the dentists’ scientific muster. The notorious serial murderer Ted Bundy’s 1979 case brought these dentists and their work to national attention and other courts’ approval of them became established as good precedent for future court bitemark admissibility throughout the nation. The ABFO test required nothing more than agreeing with these proponents and moving forward within the organization. I did find a bitemark case to review in order to complete my application as I was given access to a local District Attorney homicide investigation where an opinion from one of these nationally known dentists had claimed that bruising on the decedent’s face was a bitemark and one of four suspects was the biter. My recommendation was the exact opposite and I stated that the vague bruising to be insufficient for analysis. The case never went forward from that point. That same dentist later became involved in the bitemark prosecution of Ray Krone which is the subject of a chapter in this issue of the JCDA.

Starting in the 1990’s, I continued doing dental ID casework in Ventura, and began cross-training in other forensic areas. I became a Certified Senior Crime Scene Analyst, took classes in forensic osteology, DNA profiling, obtained a degree in Anthropology, went to law school and passed the California Bar exam. The Juris Doctor degree helped me in areas of understanding legal thinking and writing The Anthropology and DNA subjects clearly had the most forensic impact due to new knowledge I obtained on the variability of human individuality. In 1995, I wrote a short op-ed to my ABFO colleagues letting them know that DNA would begin coming into court as an independent vehicle to either support or refute their bitemark opinions. Some began to add a contingency disclaimer to their opinions that, in the event of DNA results, their bitemark opinion would be “reconsidered.” I took that as an improvement of some value, but in 2016, ABFO leaders testified to an investigation by the Texas Forensic Science Commission that they would “only specialize in non-DNA cases.” This illuminated their blatant arrogance in the face of DNA having undermined the foundations of bitemark “science.” The Commission’s response was a recommendation for a “moratorium on the future use of bitemark analysis (in its entirety) until additional scientific research be done. In 2022, the National Institute of Science and Technology published the proceedings of its 2019 scientific review of bitemark comparisons. This Institute issued the same criticisms expressed by the Texas Commission.

In 1999, I received a request to contribute my opinions about bitemark comparisons for a legal encyclopedia titled “Modern Scientific Evidence: The Law and Science of Expert Testimony” (5 volumes) which was co-edited by David F. Faigman (Chancellor of Hastings Law) and Distinguished Law Professor Michael Saks (Arizona State University). Both are legal specialists in evidence law, the law’s use of science, Constitutional law and scientific methods. My part was to systematically apply the scientific method to the dental area of bitemark comparisons. The results were unfavorable for my bitemark colleagues due to: 1) inadequacies of proficiency testing, 2) too many allowable methods of comparison (x-rays, Styrofoam bite exemplars, xerox copies of skin injuries, and computer imaging to crayon drawn outlines, 3) the inaccuracy of skin as a substrate for bitemarks, 4) no scientific proof of skin being able to record accurate tooth markings, 5) no testing on the assumed uniqueness of the human dentition reflected in bitemarks, and 6) casework where DNA contradicts bitemark opinions. It is notable that this compendium and bitemark chapter are still in print in the later editions of the work. The relevance of this information is clear. It has been favorably reviewed, quoted, and paraphrased, and in part, adopted by notable forensic science review boards of the National Research Council, two Congressional subcommittees on forensic science, National Academy of Sciences, the National Institute of Science and Technology and the President’s Council of Advisors on Science and Technology.

Since the late 1990’s, I have been involved as a dental consultant in portions of 12 post-conviction appellate cases where prosecutors have used bitemark comparisons as an aid for wrongful convictions. The Innocence Project and the Innocence Network have continued this process of identifying the weak, illogical and plainly junk bitemark “science” within the US criminal court system. These advocates express the logic that advances of science (i.e., DNA and better courtroom understanding of science versus pseudoscience) should be reflected in the rules of law in order to prevent future damage to the lives and liberty of criminal defendants who are factually innocent. Special recognition should be given to those dental, legal and scientific professionals who have given major assistance in this pursuit of better scientific methods for standards of care involving forensic dentistry.

Additional information

Notes on contributors

C. Michael Bowers

C. Michael Bowers is a retired general dentist and a licensed attorney in California. He is a multiple AAP PROSE award winning author/editor for ‘Forensic Testimony: Law, and Forensic Science (2015) and The Psychology and Sociology of Wrongful Convictions (2018) and contributor to over 2 dozen peer-reviewed journal articles and chapters in other texts. He is currently a forensic dental identification consultant for a Missing and Unidentified Persons unit of the US Department of Justice.