Date of Award
Doctor of Philosophy (PhD)
Daniel B. Blinka
Denis Lynch, Ramesh Sachdeva, Thomas Taft
The credibility of bite mark analysis as a forensic science is under fire in our legal system. The basis of opinions regarding the probability of a dental pattern observed in bite mark evidence matching a suspect's dentition has not been objectively substantiated. Though guidelines and standards are in place, bite mark analyses have failed to provide basic scientific methods in order to be deemed of evidentiary value. Forensic scientists need to take a step back and develop valid and reliable methodologies that provide a statistical approach for defining dental characteristics in the human dentition.
For this study, three computer-generated, mathematically derived curves were chosen to describe and quantify in a statistical manner the dental characteristic of displacement of eight anterior teeth in the human dentition. The Bezier, ellipse, and polynomial curves were digitally applied to scanned images from 75 dentitions comprising 150 wax exemplars of dental imprints of a male population, ages 18-44. Measurements of each tooth were made using Adobe Photoshop® software to provide maximum standardization and objectivity. Statistical tests established the best-fit-curve for determining displacement of the anterior teeth.
Of the three curves, the polynomial curve had the lowest average of variance and the lowest sum of the absolute value of displacement from the curve for the anterior teeth; thus, it was shown to be the best-fit-curve based on the statistical variance for measuring displacement of the anterior teeth. Allowing for tooth displacement to be a measurable dental characteristic that can be scientifically quantified, the polynomial curve provides a valid and reliable methodology for bite mark analysis in future population studies.
The polynomial curve may significantly enhance the judicial process associated with bite mark evidence by providing a scientific basis for objective interpretation of a unique dental characteristic based on an individual curve and the individuality of a bite pattern or imprint from a victim and/or suspect(s).