Molar crown thickness, volume, and development in South African Middle Stone Age humans (original) (raw)

Dental remains from three MSA localities were examined: Die Kelders Cave, Equus Cave, and Blombos Cave. Unworn and lightly worn molar teeth were selected for imaging with conventional laboratory mCT (ScanCo mCT 20, Stony Brook University) or synchrotron mCT on the beamline ID 19 at the European Synchrotron Radiation Facility (Grenoble, France) with a voxel size of 16 mm. The use of a third-generation synchrotron for mCT of fossil teeth provides several advantages over laboratory mCT, including a monochromatic beam, rapid scan time, a high signal to noise ratio, and parallel beam geometry, leading to higher quality resultant images. 15,16 Nonetheless, these two scanning systems yield comparable data for fossil teeth that are not substantially remineralized during fossilization, 17 and both systems produce accurate dental measurements. Although more than 50 teeth were examined from the three localities, only four unworn or lightly worn permanent molars were available for the study of enamel thickness, tissue volumes, and crown formation (SAM-AP 6242, 6277, 6282; EQ H5). Enamel thickness was quantified via traditional two-dimensional (2D) methods 19 for comparison with previous studies, as well as by newly developed three-dimensional methods, 10,15,20 which represent a whole-tooth approach, and capture the distribution of enamel thickness across the entire molar crown.