Computer-based method of bite mark analysis: A benchmark in forensic dentistry?

AIM: The study aimed to determine the technique with maximum accuracy in production of bite mark overlay.

MATERIALS AND METHODS: Thirty subjects (10 males and 20 females; all aged 20-30 years) with complete set of natural upper and lower anterior teeth were selected for this study after obtaining approval from the Institutional Ethical Committee. The upper and lower alginate impressions were taken and die stone models were obtained from each impression; overlays were produced from the biting surfaces of six upper and six lower anterior teeth by hand tracing from study casts, hand tracing from wax impressions of the bite surface, radiopaque wax impression method, and xerographic method. These were compared with the original overlay produced digitally.

RESULTS: Xerographic method was the most accurate of the four techniques, with the highest reproducibility for bite mark analysis. The methods of wax impression were better for producing overlay of tooth away from the occlusal plane.

CONCLUSIONS: Various techniques are used in bite mark analysis and the choice of technique depends largely on personal preference. No single technique has been shown to be better than the others and very little research has been carried out to compare different methods. This study evaluated the accuracy of direct comparisons between suspect's models and bite marks with indirect comparisons in the form of conventional traced overlays of suspects and found the xerographic technique to be the best.