SILVA, N. T. D.; SILVA, Nádia Tainá Diniz da.
Résumé:
The Legal Dentistry acts in the identification of living persons and cadavers through
the dental arch and is based on the individual characteristics of the dental elements and on the
resistance of these elements the extreme environmental conditions. Bite marks are described
in the literature as important expert elements for identifying victims and criminals, are very
common in crime scenes and are often the only criminal traces the forensic odontologist can
count on during the investigation. Faced with this, the study of dental impressions has been
increasingly relevant and necessary. This work aims to analyze the accuracy of the screening
techniques commonly used in the analysis of bite marks and the possibility of identification of
the author of the bite in food substances. The sample was selected after approval by the Ethics
Committee and had 30 students from the dentistry course of the Federal University of
Campina Grande - Patos campus, which had all the anterior upper and lower natural teeth.
The work consists of two phases. In the first phase, the 30 selected students were cast with
alginate and cast in stone gypsum. The upper and lower anterior teeth of the gypsum models
were drawn in a transparent acetate sheet with a 0,5 mm felt tip. Three tracing techniques
were simulated: manual, wax and radiographic printing from the wax impression by
confronting the acetate sheet previously delineated to determine the match. In the second
phase, seven of the 30 students belonging to the sample bitten two food substances: cheese
and guava. The molding of these foods was carried out and, later, the models in plaster were
obtained. These templates were confronted with acetate sheets to determine matching. The
evaluation was performed by two examiners, and for the calibration, 20 models of gypsum
were used that were not part of the sample, using exactly the same methodology described
above, which lasted 2 (two) weeks. the analysis of intra and inter-examiner agreement was
done by means of the kappa test (0.89 and 0.81, respectively). Blinding was done by
removing all posterior teeth and palatal wrinkles to eliminate bias. All of the screening
methods presented good results, with manual tracking showing the best results with excellent
correspondence in 90% of cases, followed by wax printing with 76.7% and finally the
radiographic method with only 26.7%. In the two food substances it was possible to correctly
identify all the authors of the bite, and the guava presented better results with 87.5% of the
cases with excellent correspondence, and the cheese with 57.1%. It is concluded that the
tracing techniques analyzed presented good results and can be used in practice as long as they
are executed correctly. Foods also presented excellent results, where guava presented as a
better substrate for bite analysis than cheese, showing that they can serve as reliable and
accurate evidence for the identification or exclusion of suspects.
