The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

A geometric morphometric analysis of lower deciduous first molars and their succedaneous dentition


Anthropology, Indiana University

Saturday All day, Park Concourse Add to calendar

Lower deciduous first molars (ldm1) are rarely studied despite their unique shape and occlusal arrangement relative to all other teeth in the permanent and deciduous dentition. Research available on deciduous first molars includes metric and discrete trait analysis. There are no published studies using geometric morphometric methods on human deciduous molars in relation to their succedaneous dentition. Shape analysis may offer additional insight into earlier evolutionary dental shapes or the processes behind dental development. Geometric morphometric analysis was conducted on ldm1s, lower first premolars (LPM1) and lower first permanent molars (LM1) to examine which of these two permanent teeth the deciduous first molar most closely resembles. Landmark and outline shape analysis was done using Wolfram Mathematica. Procrustes, principal components and ANOVA tests were run on the sample. Results show that each of the three tooth categories cluster distinctly from each other despite molars being the same tooth type. Furthermore, the ldm1 has the most variation within its category. The ldm1 is statistically different from LPM1 but not LM1 suggesting that it is morphologically closer to a molar than its succedaneous premolar. Further investigation of the ldm1 may find that its unusual shape is related to an earlier evolutionary molar shape or is simply a product of complicated dental development.

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