24 ON ABSORPTION. 



montlis after the accident, accompanied with a 

 similar absorption of the alveolar walls. 



Again, a tooth that has been fractured by a blow, 

 but not dislodged, may absorb at the point of the 

 injury. 



Fig. 2, Plate II., illustrates an upper bicuspid 

 tooth that had been so injured. It remained for 

 two or three years free from inconvenience. Absorp- 

 tion gradually encroached upon the structure from 

 before and from behind, and ultimately the tooth 

 rocked upon a central pivot. It then became pain- 

 ful, and was consequently removed. 



rig. 3, Plate II., is taken from a tooth in which 

 absorption of the fangs was the result of irritation, 

 caused by salivary calculus having been deposited 

 in one of the alveoli, in which the roots of the tooth 

 are implanted. The tooth was strong, healthy, 

 and firm. It was removed in consequence of acute 

 local pain. 



In Fig. 4, Plate II., we have an example of a 

 different kind. It is usually met with in old persons, 

 whose teeth are getting loose, when the sockets 

 fill up, and the walls of the alveoli equally pass 

 away by the same process, as if nature was approach- 

 ing that period when their loss would not be felt. 

 It may with propriety be denominated " Senile 

 absorption." 



Normal absorption is an economy in nature for an 

 especial purpose. We consequently perceive that the 

 process corresponds to the position of the new tooth. 



