where, {HEAD ~ Y}: crowning {TAIL ~ curve} having an origin at the tooth surface at the center of the tooth thickness, 
crowning
where , { HEAD ~ Y } : crowning { TAIL ~ curve } having an origin at the tooth surface at the center of the tooth thickness ,
OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH