Forensic Study On 3D Technology In Human Bitemark Identification

Objective:Bite mark identification is based on the individuality of a dentition, which is used to match a bite mark to a suspected perpetrator. This study presents a technique developed for 3-D imaging and quantitative comparison of human dentitions and simulated bite marks,which could provide a new technology for personal identification based upon dentition and bite mark for forensic medical practice.Methods:A sample of 60 study models and the corresponding bites, made by animal experiments , were digitised by laser scanning. By image comparison of a 3-D dentition with a 3-D bite mark, a number of variables comprising curves, angles and distances were created using the x, y, z co-ordinates of each landmark providing a numerical description of the dentitions and bite marks. An algorithm, which estimated the probability of a dentition matching its corresponding bite mark, was developed. A receiver operating characteristic(ROC) graph illustrated the relationship between values for specificity and sensitivity.Results:Image comparison of a 3-D dentition with a 3-D bite mark can eliminate the distortion due to perspective as experienced in conventional photography , The probabilities generated by the variables were expressed ,P(TP) means the probability of obtaining a match for dentitions and bites that do in fact match; P(TN) means the probability of obtaining a non-match for dentitions and bites that do not in fact match; P(FP) means the probability of obtaining a match for dentitions and bites that do not in fact match; P(FN) means the probability of a non-match for dentitions and bites that do in fact match. These probabilities were expressed in an ROC curve .Conclusion:In this study,the technique developed for 3-D imaging and quantitative comparison of human dentitions and simulated bite marks, could provide a new technology for personal identification based upon dentition and bite mark for forensic medical practice.It was more accurate at matching the correct bite mark to the correct model.This method is one of the bases in studying personal identification based upon dentition and bite mark.