(1) crown 1)buccal aspect a buccal cusp less pointed, mes ly mesial ridge shorter b buccal axial ridge less pointed; deve lopmenta l grooves Iess pr om i nence
（1）crown 1）buccal aspect a.buccal cusp less pointed,mesially mesial ridge shorter b.buccal axial ridge less pointed;developmental grooves less prominence
Crown 2)Lingual aspect little variation cusps al most same length crest of contour middle third
Crown 2）lingual aspect little variation cusps almost same length crest of contour:middle third