X: {HEAD ~ axial distance} from the origin at the tooth surface at {TAIL ~ the center} of the tooth thickness, 
X : { HEAD ~ axial distance } from the origin at the tooth surface at { TAIL ~ the center } of the tooth thickness ,
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH