Variation of 3D outer and inner crown morphology in modern human mandibular premolars

Viktoria A. Krenn, Cinzia Fornai, Lisa Wurm, Fred L. Bookstein, Martin Haeusler, Gerhard W. Weber

This study explores the outer and inner crown of lower third and fourth premolars (P3, P4) by analyzing the morphological variation among diverse modern human groups.

We studied three‐dimensional models of the outer enamel surface and the enamel–dentine junction (EDJ) from μCT datasets of 77 recent humans using both an assessment of seven nonmetric traits and a standard geometric morphometric (GM) analysis. For the latter, the dental crown was represented by four landmarks (dentine horns and fossae), 20 semilandmarks along the EDJ marginal ridge, and pseudolandmarks along the crown and cervical outlines…

How Amira-Avizo Software is used

The image stacks were imported in Amira 6.7 and virtually segmented to isolate the dental crown and separate the dentine from the enamel. We applied a semiautomatic segmentation based on the half‐maximum‐height value protocol proposed by Spoor, Zonneveld, and Macho (1993). Afterwards, we generated 3D virtual surface models for both the OES and the EDJ.