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