Morphology, wear and 3D digital surface models: materials and techniques to create high-resolution replicas of teeth

Abstract

Many anthropological studies are derived from the analysis of dental casts. Dental morphology plays a key role for taxonomy (Wood, 1991), diet and ecological assessments (Swindler, 1976). Tooth wear provides information about food composition (Ungar, 2007), environment, cultural habits (Hinton, 1981), jaw movements (Kay & Hiiemae, 1974), health conditions (King et al., 2005) and determination of age-at death (Lovejoy, 1985). Today, the study of dentition derived from 3D surface models enables us to obtain more detailed information (Kullmer et al., 2002; Ungar & M'Kirera, 2003) about tooth function and wear. In most cases it is not possible to use the original material directly due to limited access and study-time constraints, and/or methods which cannot be directly applied to the collections, such as analysis through the use of a scanning electron microscope (SEM), which requires an irreversible gold-coating to be added to the specimen. Even if one has taken photographs, micro CT, or 3D surface scans for digital model reconstruction, at the very least it can be advantageous to keep a high quality cast close to hand during the study, as some information can be lost during transition from original to digital format. Replicas of dentition could be created from digital models using rapid prototyping (stereolithography), although the costs remain high and the resolution is only suitable for the analysis of tooth morphology and mesowear. Therefore, it is of great benefit to establish a laboratory with all the principal equipment necessary to produce high-resolution dental replicas for anthropological studies. This contribution provides several guidelines for producing high-quality dental casts.