Scanning electron microscopy in the investigation of bite marks in foodstuffs

The purpose of the present study was to assess the value of utilizing SEM in the examination of bite marks in foodstuffs. Six students, whose front teeth showed no conspicuous irregularities, were asked to bite off a part of some selected foodstuff consisting of butter, cheese, Norwegian brown sweet cheese, apples, carrots, bananas, chocolate and chewing gum. The texture and the varying stickiness of the foodstuffs seemed to be of significance as far as the details of the bite marks were concerned. In butter, chewing gum and Norwegian brown sweet cheese, fine details were discerned, thus justifying the use of SEM. Both scratch marks of the front teeth and impression marks of the incisal edges were studied. Only the latter revealed details of value for the identification by means of the SEM. Often small enamel defects were found at the incisal edge of the front teeth. These defects showed a great number of individually characteristic details. Where dentin was exposed at the incisal edge, further characteristic details could also be found. Thus, the use of SEM seemed to be of value in special cases as a supplement to conventional investigation methods.