Forensic Odontology and Bite Mark Analysis: Understanding the Debate

Forensic odontology is the application of dental knowledge that we all share as dental health-care professionals to the field of law enforcement and death investigations. The most common dental application and the application the readers are familiar with is postmortem (after death) dental identification (ID) of a decedent who cannot be identified by typical legal means (fingerprint, scars, marks, tattoos, medical implants and devices, and DNA). Forensic dentists participate in the mass disaster arena with identification as well. Though dental ID is the most common, forensic dentists are also called upon to 1) estimate the age of an individual both alive and/or deceased, 2) assist in the civil litigation field, and 3) bite mark assessment. Bite mark assessment involves assessing whether a mark is caused by a bite (see Figure 1) and/or assessing if an individual person or animal “biter” made the mark on a substrate, such as human skin or an inanimate object (see Figure 2).

Figure 1. Bite mark wound on human epidermal tissue. Source: Anthony R. Cardoza, DDS, D-ABFO.

Figure 2. Bite mark with analytical overlay of mandibular incisal edges. The overlay is inverted for proper orientation. Source: Anthony R. Cardoza, DDS, D-ABFO.

Contemporary bite mark investigations began with the People vs. Marx case in 1975 in Los Angeles, CA. This homicide case had evidence that the victim had been bitten on the bridge of her nose (see Figure 3). The prosecution used suspect biter/bite mark evidence in the presentation of their case. The bite mark evidence was considered “novel” scientific evidence and underwent a Kelly-Frye scientific evidence challenge by the defense. The Kelly-Frye standard of admissibility requires that a new scientific technique used by an expert witness be generally accepted within the relevant scientific community. The court upheld the use of the bite mark evidence and it was included as part of the prosecution’s evidence. This was important in the murder conviction of the suspect. Upon appeal, the bite mark evidence was again challenged. This evidence was accepted by the appellate court, which became significant for future cases involving bite marks. The successful appeal set the precedence for bite mark analysis and testimony to be used in courts in all 50 states.

Figure 3. People vs. Marx: Bite mark wound on the bridge of the victim’s nose. Source: Gerald L. Vale, DDS, D-ABFO.

While the Marx ruling set the legal precedent for bite mark usage in US courts, the case that put bite marks as evidence on the map was a case that should ring very familiar, People vs. Bundy in Florida in 1978. Ted Bundy had bitten one of the sorority house victims on the buttocks area during his deadly attack (see Figure 4). This bite mark was used as evidence in the murder trial of Bundy. Bundy was convicted and sentenced to death and admitted that the bite mark evidence was a key piece of evidence. Because of the high-profile nature of this case, bite mark analysis went “viral” after this conviction and their use in the court system skyrocketed. Bite mark analysis had now become mainstream and their use as evidence became widespread from that time on through the 2000’s.

Figure 4. People vs. Bundy: Bite mark wound on buttocks of victim. Source: Richard Souviron, DDS, D-ABFO.

As bite mark casework progressed, it started to become evident to some odontologists that the opinions of bite mark patterns and bite mark analysis were not consistent between “experts.” This was frequently seen in trials as well. For instance, in People vs. Milone, a trial in Illinois in 1976, there were six odontology experts for the prosecution and five for the defense! Even though reliability and validity of bite mark analysis had not been established, bite mark testimony continued to be accepted by the courts. The prosecution could have a credible expert odontologist testify before the court to an opinion of reasonable dental certainty (match) that a biter had indeed made the bite mark wound, thus placing the suspect at the scene and linking them to the crime which greatly enhanced their case. This was an era before the use of DNA of which its analysis can quantitatively place the subject at the scene.

These ongoing concerns over lack of reliability and validity with bite mark opinions continued well into the first decade of the new millennium. We saw a history of bite mark workshops with less than stellar results further clouding reliability and validity. Quite simply, forensic dentists analyzing bite marks often did not agree on the degree of certainty linking a suspect to the mark and even worse there was often disagreement whether a wound was even a bite mark or not. The release of the National Academy of Sciences report in 2009 that reviewed all forensic science disciplines released a scathing opinion of bite mark analysis and its usage. It was the exoneration of an innocent man, Ray Krone, who had been convicted of capital murder and sentenced to death in 1991, re-tried and convicted again in 1996 based primarily on bite mark evidence that began to change the conversation. Krone was finally exonerated and released from prison in 2002 based on newly examined DNA evidence collected at the scene. This exoneration opened the eyes of many experts to the potential perils of the use of bite mark analysis/evidence in the court system. The Hon. Christopher J. Plourd, Judge Superior Court of Imperial County, California, acted as the defense attorney for Mr. Krone in his retrial in 1996 and contributes an article of Mr. Krone’s wrongful conviction case. To date, there have been 38 wrongful convictions and indictments where bite mark analysis was determined to be wrong.

This special collection of the Journal is a review of the debate over bite mark analysis. C. Michael Bowers, DDS, JD offers a personal perspective on his experience with bite mark analysis historically to present day. Mary A. Bush DDS, Raymond G. Miller DDS and Peter J. Bush BS of the School of Dental Medicine, State University of New York at Buffalo, present a review of their bite mark research and include responses from the legal, forensic odontological and scientific communities. Richard Fixott, DDS, Diplomate of the American Board of Forensic Odontology (ABFO) and Past President of the ABFO discusses the ABFO standards and guidelines for bite mark analysis both historically where terms such as “without a doubt” or “match” were used to identify a perpetrator of a bite mark. He then shows how the current version of guidelines has evolved to today’s standards where terms of “absolute” or “match” are now no longer recommended. Instead, blind gathering of data, the use of second examiners and terms like “can exclude and cannot exclude” are recommended.

John D. McDowell, DDS, MS, D-ABFO, Professor-Clinical at the University of Colorado School of Dental Medicine, Aurora, Colorado, presents his opinion on the future of bite mark analysis, specifically the absence of gold standard or ground truth in bite mark analysis. We also have M. Chris Fabricant, Director of Strategic Litigation for the Innocence Project, New York, New York, who shares a chapter from his recent book released last year titled “Junk Science and the American Criminal Justice System.” His book examines the role that faulty scientific evidence has in continuing and strengthening an unjust and racial biased criminal legal system, and this chapter discusses the origin of the Innocence Project in New York City’s Cardozo School of Law in 1992.

In summary, my hope is that you the reader upon reading this special collection of the Journal will have a better understanding of bite mark analysis along with the challenges it has faced in the past, and faces in the present, and future. I also wish to dedicate this Journal to two giants in the forensic field who are , sadly, no longer with us, Dr. Norman D. “Skip” Sperber, DDS, Diplomate Retired Emeritus ABFO and Gerald L. “Jerry” Vale, DDS, JD, Diplomate Retired Emeritus ABFO. These two doctors mentored many in the forensic field, and I am proud to have called them my friends as well as mentors.

Additional information

Notes on contributors

Anthony Cardoza

Anthony Cardoza, DDS, D-ABFO is a forensic dental consultant for the County of San Diego Office of the Medical Examiner, County of Imperial, Office of the Coroner, State of California Department of Justice. Dr. Cardoza graduated from Northwestern Dental School in 1985 and maintains a general dental practice in San Diego, California. Dr. Cardoza is a Fellow of the American Academy of Forensic Sciences and is a Diplomate of the American Board of Forensic Odontology.