CEMEin: FILLING THE PULP'S OFFICE. 169 



life, may cause caries. Prof. Williams says (" Princi- 

 ples and Practice of Veterinary Surgery," p. 470) : 



'^ Caries, dental gangrene, or decay, is almost exclu- 

 sively confined to tlie grinder teeth — although I have 

 seen the incisors in that condition — and may begin 

 primarily in the root, neck, or crown of the tooth. 



" Caries of the root arises from inflammation of the 

 pulp, and may be caused by a constitutional predispo- 

 sition or external injury. Inflammation of the pulp, 

 however, does not always cause caries. I have several 

 cases on record where the roots were enlarged from 

 periodontal deposit, with abscesses surrounding the 

 roots, without caries. Caries beginning at the roots 

 may be due to the obliteration of the pulp-cavity at 

 an age when the vitality of tlie tooth depends upon 

 the integrity of the pulp. I need scarcely remind the 

 professional reader that the integrity of the teeth de- 

 pends upon a due supply, both as to quantity and 

 quality, of nutritive materials. 



" On the roots of a recently cut tooth but little 

 cement is met with compared with that which exists 

 in old teeth. As age advances the cement increases, 

 and the tooth grows from the outside. In man it is 

 generally agreed that after a given time the dentine 

 ceases to be produced, and that the pulp is converted 

 into osteodentine. In the horse the pulp-cavity be- 

 comes obliterated gradually by the pulp continuing to 

 form dentine, the pulp simply giving way to its own 

 product, which ultimately occupies its place and fills 

 its cavity. In proportion as the pulp diminishes the 

 supply of nutriment is lessened, until at length it is 

 entirely cut off from the interior; to provide for the 

 vitality of the tooth the cement increases in quantity 



