CHAPTEE V. 



DEVELOPMENT AND MOKPHOLOGY . OF THE TEETH. 



The Structure of a Tooth. — A tooth may be considered as 

 made up of five parts (see Fig. 47) : 



(1) The pulp, situated within (2) a capsule of dentine; the 

 exposed part or crown of the dentine is coated by (3) the enamel ; 

 the imbedded part or root by a layer of bone— (4) the crusta 

 petrosa. The root is secured within its socket by (5) the 

 peridental membrane, which acts as a periosteum to both the 



enamel 



dentine 



odonto-blasts 



pulp 



crusta petrosa 

 epidermis of gum 

 ■peridental membrane 



alueolus 



dental canal 

 and artery 



Flo. 47. — Showing the parts of an incisor tooth. 



crusta petrosa and bony wall of the tooth socket. An account of 

 the development of a tooth has to deal with the origin of each of 

 these five parts. 



