Methods: Silicone impressions of the upper anterior teeth were collected from 20 consenting volunteers. These were cast in white orthodontic stone to produce models of the anterior dentitions. The models were scanned on a flat bed scanner and imported into Adobe Photoshop 7TM and saved as JPEG files. For each scan, rotational analysis was undertaken on the upper incisors and canines using the method, originally described as part of the technique for digital bite mark analysis (Johansen RJ & Bowers CM, Forensic Imaging Services, 2000). The rotational values obtained from the analyses were recorded and grouped into 10 degree ranges for each tooth. A control value for each tooth was obtained by setting denture teeth to an ‘ideal’ arch shape using an orthodontic template; this ‘denture’ model was also scanned and analysed.
Results: Compared to the respective control value, distopalatal rotation of an upper right incisor or canine increased the rotational value; mesiopalatal rotation of an upper right incisor or canine decreased the rotational value; distopalatal rotation of an upper left incisor or canine decreased the rotational value and mesiopalatal rotation of an upper left incisor or canine increased the rotational value. For each of the six teeth studied from the 20 subjects, moderate to severe distopalatal rotations appeared more frequent than moderate to severe mesiopalatal rotations.
Conclusions: Preliminary results suggest that moderate to severe mesiopalatal rotation may have potential for use as a discriminator in bite mark analysis.