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Comparative Reliability Analysis of Computer-Generated Bitemark Overlays

NCJ Number
209102
Journal
Journal of Forensic Sciences Volume: 50 Issue: 2 Dated: March 2005 Pages: 400-405
Author(s)
Anne H. McNamee D.D.S; David Sweet D.M.S; Iain Pretty B.D.S
Date Published
March 2005
Length
6 pages
Annotation
This study compared the reliability of two methods for producing computer-generated bitemark overlays with Adobe Photoshop (Adobe Systems, Inc., San Jose, CA).
Abstract
Scanned images of 12 dental casts were sent to 30 examiners with varying levels of experience, and they were instructed to produce an overlay for each cast image based on the instructions provided for the 2 techniques. Measurements of the area and the x-y coordinate position of the biting edges of the anterior teeth were obtained with the Scion Image software program (Scion Corporation, Frederick, MD) for each overlay. The inter-reliability and intra-reliability assessment of the measurements was conducted by means of an analysis of variance and calculation of reliability coefficients. The assessment of the area measurements found significant variances in the examiner variable for both techniques, resulting in low reliability coefficients. On the other hand, findings for the assessment of the positional measurements showed no significant differences in variance among examiners, producing exceptionally high reliability coefficients. Thus, both techniques proved reliable in producing bitemark overlays to assess tooth position. The authors advise that the next step is to test the external validity of bitemark overlays, which would include having examiners both produce and use their original overlays in a simulated bitemark comparison. Other suggestions for related future research are also offered. 4 tables, 4 figures, and 8 references