A robust alternative to assessing three-dimensional relative enamel thickness for the use in taxonomic assessment

Measuring Dental Enamel Thickness: Morphological and Functional Relevance of Topographic Mapping

The interest in the development of dental enamel thickness measurement techniques is connected to the importance of metric data in taxonomic assessments and evolutionary research as well as in other directions of dental studies. At the same time, advances in non-destructive imaging techniques and the application of scanning methods, such as micro-focus-computed X-ray tomography, has enabled researchers to study the internal morpho-histological layers of teeth with a greater degree of accuracy and detail. These tendencies have contributed to changes in established views in different areas of dental research, ranging from the interpretation of morphology to metric assessments. In fact, a significant amount of data have been obtained using traditional metric techniques, which now should be critically reassessed using current technologies and methodologies. Hence, we propose new approaches for measuring dental enamel thickness using palaeontological material from the territories of northern Vietnam by means of automated and manually operated techniques. We also discuss method improvements, taking into account their relevance for dental morphology and occlusion. As we have shown, our approaches demonstrate the potential to form closer links between the metric data and dental morphology and provide the possibility for objective and replicable studies on dental enamel thickness through the application of automated techniques. These features are likely to be effective in more profound taxonomic research and for the development of metric and analytical systems. Our technique provides scope for its targeted application in clinical methods, which could help to reveal functional changes in the masticatory system. However, this will likely require improvements in clinically applicable imaging techniques.

Similarities and differences in the dental tissue proportions of the deciduous and permanent canines of Early and Middle Pleistocene human populations

The two- and three-dimensional assessment of dental tissues has become routine in human taxonomic studies throughout the years. Nonetheless, most of our knowledge of the variability of the enamel and dentine dimensions of the human evolutionary lineage comes from the study of permanent dentition, and particularly from molars. This leads to a biased view of the variability of these features. Due to their early formation and rapid development, the deciduous teeth allow more simplified inferences regarding the processes involved in the dental tissue development of each group. Therefore, their study could be very valuable in dental palaeohistology. In this research, we have explored the dental tissue proportions of the deciduous canines belonging to some human samples of the Early and Middle Pleistocene. The purpose of this was to discuss the meaning of the similarities and differences observed in their histological pattern, as well as to evaluate the degree of covariance with that observed in the permanent dentition of these populations. Our results show that, although there are some similarities in the dental tissue proportions between the deciduous and permanent canines of the study samples, the two dental classes do not provide a similar or comparable pictures of the dental tissue pattern present in the dentition of fossil hominins. Future works on the dental tissue patterns of the anterior and posterior dentition, including deciduous teeth, of fossil samples, may help to shed light on this hypothesis.