Page 6 - COS-FOD2015
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Compend. Oral Sci:vol1(1);2015;1-5



                Materials and methods                           resizing.  Formula  to  measure  the  photographs
                                                                resizing  is  as  follows;  the  real  size  of  scale  =
                Two independent operators were working on this
                                                                scale size (actual) and resize ratio = scale size
                project.  First  operator  simultaneously  acted  as
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                                                                (actual)/scale  size  (image) .  Suspect  cast  was
                victim  and  suspect  by  self-inflicting  a  bite  mark
                                                                scanned  (Fig.  2)  and  overlay  fabrication  was
                injury on his forearm. The second operator (the
                                                                made. The overlay comparison was then initiat-
                author)  acted  as  forensic  odontologist  who  un-
                                                                ed. “Magic wand” tool was utilized to select the
                dertaking the whole process of bite mark identifi-
                                                                tooth edges. Non-metric overlay comparison pro-
                cation  and  analysis.  The  outline  of  the  self-
                                                                cedures using manual digital analysis and spatial
                inflicted  bite  mark  must  be  clear  and  free  from
                                                                polygon were used in this trial. The spatial poly-
                external marks such as scars, tattoos, and heavy
                                                                gons of both bite mark image and scanned cast
                hairs (Fig. 1).  Prior to bite mark infliction, a fore-
                                                                were manually compared by patterns and sizes.
                arm rest (blue arrow) was constructed to repro-
                duce  the  same  angulation  during  photography.

                The  bite  marks  were  digitally  photographed  ac-
                cording  to  ABFO  recommendation  for  evident
                         6
                collection   with the ABFO No. 2 ruler placed in-
                   7
                situ . Impression casts were constructed on the
                suspect’s  dentition.  The  photographs  were
                stored in JPEG format.
















                                                                 Figure:  2  –  Scanned  casts  of  upper  and  lower

                 Figure: 1 – Digital bite mark photograph in fore-
                 arm rest cast (blue arrow)                     Results and Discussion

                                                                The  image  distortion  was  fixed  using  grid  by
                Digital analysis
                                                                equalizing  the  legs of the  scale. Angular distor-
                The  casts  were  scanned  with  a  2-D  Canon   tion  was  not  fixed  as  the  ruler  circle  perfectly
                PIXMA™ MG3220 scanner (Canon U.S.A., Inc.,      fitted  to  each  other  (Fig.  3).  The  image  height
                New York). The 2-D images were then imported    and width were obtained as 4.84cm and 8.33cm,
                to  Adobe  Photoshop®  software  and  processed.   respectively. The resize ratio  was calculated as
                The  digital  analyses  were  performed  in  the  fol-  0.735  where  the  scale  size  (actual)  was  5mm
                lowing steps. First, the detection and correction   (0.5cm)  and  scale  size  (image)  was  6.8mm
                of digital photographic distortion were performed   (0.68cm). Therefore, the height and
                followed by photographs



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