The Accuracy Of 3D Digital Analysis Applied To The Study Of Bite Marks Identification

Objective: The objective of the study was to compare the accuracy of the evidence of bite marks obtained by scanning bite marks with a 3D scanner and shooting bite marks with a traditional digital camera,so as to provide a theoretical basis for the future application of 3D scanning technology in dental forensic.Methods: 17 pairs of models were selected according to inclusion and exclusion criteria,and 17 pairs of dental models were scanned with 3Shape scanner,and data were type into the computer.Overlay data of the front teeth area of bite marks were obtained by using digital camera and 3D scanner respectively.Comparing the overlays parameters of the front teeth area of bite marks obtained by the two methods respectively with overlays parameters of the front teeth area of the research model.Results: The results of multivariate analysis of variance showed that there were statistically significant differences in the parameters of incisor ridge thickness,incisor ridge width,maxillary arch mandibular arch among the three groups(standard group,traditional group and 3D group).There were no statistically significant differences among the three groups in tooth rotation and interdental Angle.The results of Mahalanobis distance statistics showed that there were statistically differences among the traditional group,the 3D group and standard group in the parameters of the thickness of the incisor ridge,the width of the incisor ridge,the maxillary arch and the mandibular arch(P < 0.05),but the difference between the 3D group and the standard group was smaller than that between the traditional group and the standard group.There was no significant difference between the traditional group and the 3D group(P > 0.05)in dental rotation and interdental Angle.Conclusion: The accuracy of obtainning the bite marks overlay by scanning bite marks with a 3D scanner was higher than shooting with a traditional digital camera.