The Uniqueness of the Human Anterior Dentition: A Geometric Morphometric Analysis

Abstract

The analysis of bitemarks has a significant bearing on forensic odontology and has attracted an increasingly sophisticated array of techniques in its evaluation. Two postulates underlie all bitemark analyses: firstly, that the characteristics of the anterior teeth involved in the bite are unique, and secondly, that this uniqueness is accurately recorded in the material bitten. Here, we investigate the question of the uniqueness of the anterior dentition. To do this, we use geometric morphometric techniques based on landmark and semilandmark data. The incisor and canine occlusal surfaces of 50 randomly selected orthodontic casts of young individuals (17-20 years) of both sexes form the material for this study. We analyzed the sizes of these teeth by means of landmark and semilandmark analysis to calculate Procrustes distances between tooth outlines. In order to analyze shape variation among individuals, we carried out principal components analyses on the partial warp scores. These are derived from Partial Procrustes coordinates aligned by means of thin-plate spline decomposition based on the bending energy matrix. The results indicate that there is no sexual dimorphism in the shape of the upper or lower arches. Plots of centroid size and first relative warps show less superposition among individuals than in shape analysis. This means that, when the size and shape are considered together, the difference between arches increases. Procrustes superimposition between the two individuals located most closely (0.0444) and the two most separated (0.1567) along the first axis of relative warp analyses show that individuals are not only differentiated by the relative position of their teeth but also by their arch shape. In conclusion, it appears that the incisal surfaces of the anterior dentition are in fact unique.

Validation of 3d Metric and Superimposition Tools in Three Software Packages for the Morphological Comparison of Laser Scanned Anterior Dentition Models

“…Different studies investigated the Similar to previous studies [9][10][11]16,17 and standard deviation were slightly higher in CC than in GS, for the mandible as well as the maxilla (Table 1). Consequently CC had more bias and less precision compared to GS.…”

“…In particular, two 9,11 and threedimensional (3D) 12,13 analyses of the human dentition were aspired; specific software for were developed 14 and tested 15 statistics…”

Forensic odontology, part 4. Human bite marks

“…It should, therefore, be possible to produce an identifiable pattern that may be reproduced on skin (or other material). Significant variability exists in the human dentition, 13 but does it create a unique dental profile, or is the problem the transfer of the pattern to skin?…”

Similarity and match rates of the human dentition in three dimensions: relevance to bitemark analysis

“…One well-established means used to describe and compare biological forms is geometric morphometric analysis (GM) [14][15][16][17][18]. GM methods allow for a quantitative analysis of shape by capturing the geometry of morphological structures of interest and preserving this information through statistical analysis.…”