The use of bite marks as damning evidence has been a controversial but powerful tool in forensic science. The ability to associate a suspect with a specific mark on the victim can be decisive in a trial. The most famous case involves Ted Bundy, where bite marks played a central role in his conviction.
On 15 January 1978, Ted Bundy broke into the Chi Omega sorority house at Florida State University, brutally attacking four women, leaving two dead. Lisa Levy, one of the victims, had bite marks on her body that would later prove pivotal in the trial. Despite the lack of other compelling physical evidence, the bite mark on Lisa Levy’s buttock became a crucial element, with forensic odontologist Dr. Richard Souviron demonstrating that the marks matched Bundy’s teeth.
Forensic dentistry plays a vital role in identifying victims and matching bite marks to suspects. Teeth, as tools, leave unique impressions that can be crucial in solving crimes. This field requires detailed analysis of dental characteristics, including chips, wear and the unique bite configuration of the suspect.
Techniques in Forensic Dentistry for Bite Mark Analysis
Initial Identification and Documentation
The first stage in bite mark analysis involves careful documentation and evidence collection. This stage is crucial to maintaining the integrity of the evidence.
- Photography: Detailed photographic techniques are used to capture the mark from multiple angles and in various lighting. The photograph must include a scale for size reference and is taken in both colour and black and white.
- Dental impressions: In some cases, impressions of the marks are taken using materials such as silicone or polyvinyl gel, especially if the mark is on a solid surface such as food or objects found at the crime scene.
Comparative Analysis
Once the bite mark is documented, a comparative analysis is made with the suspect’s dental impressions.
- Casting: Casts are taken of the suspect’s teeth, both upper and lower, to compare with the bite mark. These casts are crucial for detailed analysis and comparison with the bite mark.
- Digital Overlay: With the advancement of technology, digital overlays have become common, where images of the suspect’s teeth are digitally superimposed over the bite mark image to look for matches.
Detailed Analysis
Detailed analysis involves examining the specific characteristics of the bite mark and comparing them to known characteristics of the suspect’s teeth.
- Examination of Unique Characteristics: This includes looking for unique patterns such as chips, breaks, or wear patterns on the teeth that may exactly match the marks found on the victim.
- Bite Dynamics Study: The way the teeth are aligned when biting, the depth of the bite, and the angle of the bite are analysed to see if they match the bite characteristics of the victim.
Use of Advanced Technology
The use of advanced technology has significantly improved the accuracy of bite mark analysis.
- Photographic Enhancement: Technologies such as digital photographic enhancement can clarify images that may be blurred or unclear, highlighting details that are not visible to the naked eye.
- DNA Analysis: In cases where saliva is collected from the bite mark, DNA analysis can provide a direct link between the mark and the suspect.
Interpretation and Testimony
Bite mark interpretation requires a high level of expertise and is often the most challenging aspect of the process.
- Presentation at Trial: Forensic odontologists must be prepared to present and defend their findings in a court of law, explaining how they arrived at their conclusions.
- Cross-examination and Peer Review: The defence may question the expert on the methodology used. Peer review of the findings may be requested to ensure the validity of the results.
Conclusion
The techniques used in forensic dentistry for bite mark analysis are complex and require a high level of precision and care. While this area of forensic science can be powerful, it is also susceptible to criticism and error. The continuing evolution of techniques and technologies promises to improve the accuracy and reliability of bite mark analysis in the future.
