| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2001: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
The aim of the present project was to conduct 3-dimensionally based morphological analysis of the hominind bentition by means of using digitized whole surface datasets obtained by laser and/or ct scanning. In the present study, we developed a procedure and method of efficiently obtaining several hundreds of serial ct slices with an industrial micro-ct scanner, then extracting accurate surface rendered datasets from the 3-d volume ct data. We further developed an integrated software system that handles both laser and ct-based datasets, and conducted comprehensive accuracy tests of volume,surface area, projected area, curved lengths using test objects. We then proceeded to conduct morphometric analysis of crown features using similarly digitized parameters. The use of the ct-system allows more versatile comparative data acquisition, and we collected ct datasets of 32 human, 40 chimpanzee, 27 bonobo, 42 orangutan, and 10 gorilla molars. High quality casts were used in obtaining laser-scanned 3D datasets of 53 early hominid molars. These datasets are currently being analyzed, but we were able to characterize functionally the early hominid first molar condition. Whereas the molars of frugivorous species such as Pan and Pongo are low-crowned with broad occlusal fovea, Australopithecus and early Home molars are structurally designed to maximize occlusal surface area in a worn condition and tend to have a tall basal portion of the crown. These characteristics are common to both robust and non-robust species, despite considerable differences between the two in cusp area proportions and other morphologies.
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