An analysis of dental intercanine distance for use in court cases involving bite marks

High levels of crime in South Africa and the resulting court cases requiring bite mark evidence have necessitated continuous research into the prevalence and interrelationship of recognisable dental features present in bite marks. This study represents the largest data set of descriptive statistics related to intercanine distance, in which the means, standard deviations, medians and interquartile ranges across four racial groups were determined. Intercanine distances were also statistically weighted by determining the common, uncommon and very uncommon values for each of the racial groups. The results of this research show that we can consider any maxillary intercanine distance more than 24.1 mm and less than 43.0 mm to represent a human bite mark. Black males had the largest mean (average) intercanine distance of 36.33 mm (standard deviation 2.49 mm) and white females the smallest mean intercanine distance of 33.4 mm (standard deviation 2.13 mm). The analyses showed statistically significant differences between the mean intercanine distances of different race and gender groupings. The authors do not advocate trying to determine the race or gender from intercanine distances determined, but rather the relevance of the intercanine distances in the specific race and gender groupings. This study makes a meaningful scientific contribution to the presentation of bite mark evidence at a time when subjective opinions need to be replaced with scientific data.