Virtually Extracted Molar (IMAGE) Arizona State University Caption CT-rendered chimpanzee cranium (left) with enlarged image of a virtually extracted molar (middle). The outer layer, called enamel, is rendered transparent revealing the 3-D landscape of a molar's underlying dentine core. The location of embryonic signaling cells that will determine future cusp position is indicated by yellow spheres (middle). The distribution of these signaling centers across the dentine landscape is measured as a series of intercusp distances (red arrows in right, top), which determines the number of cusps that will ultimately develop across a molar crown, as well as the amount of terrain mapped out by each cusp (dashed lines in right, bottom). Credit Alejandra Ortiz and Gary Schwartz Usage Restrictions Image to be used for illustration of this Science Advances article only. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.