THE TEETH. 



353 



face, according to whether it is an incisor or one of the 

 bicuspids or molars. 



Permanent Teeth. Upper incisors: the labial and 



zlt 



civ 



FKJ. 154. DIAGRAM OF PREMOLAR TOOTH. WITH ALVEOLUS. 



A, bony wall of alveolus; to, enamel prisms ; zh. enamel casting: h. spaces in the base 

 of the enamel prisms ; D. dentine : dc. dentinal tnbnles ; f h, gum. with alveolar periosteum 

 below it ; C, cement ; ch, cement spaces ; f b, tooth-pulp ; i, nerve entering pulp ; v, pulp 

 blood-vessels. 



lingual surfaces are shovel-shaped, the former convex, 

 the latter concave ; the approximal surfaces are trian- 

 gular in shape, with the base at the neck, the distal 



23 



