DENTAL FISTULA. 



301 



In dogs, extraction presents no difficulty : an assistant holds the 

 animal, and human forceps may be used. The tooth is seized with 

 forceps of suitable size, and a rapid drawing movement made, usually 

 towards the tongue. Operating on the right side, traction is made 

 towards the left, and vice versa. The crown is usually firm, but the 

 root loose. The tooth key may be used if thought suitable. Artificial 

 teeth have been used in dogs. Moseley reports having fitted a full 

 set with such success that the dog could afterwards crush bones. 

 A Schipperke wearing a gold plate was exhibited at the Central 

 Veterinary Medical Society. But these 

 achievements are in the nature of scientific 

 amusements. 



DENTAL FISTULA. 



This may be defined as a tube-like cana 

 communicating at one end with the external 

 air and at the other with a tooth root or 

 socket. It almost always results from 

 alveolar periostitis, the inflammatory pro- 

 cess extending and producing an osteo- 

 myelitis purulenta, which finally leads to 

 perforation externally. Inflammation then 

 abates, until the alveolus alone remains 

 inflamed. The small quantities of pus pro- 

 duced find exit through the communicating 

 channel. 



Dental fistula occurs oftenest in young 

 horses. It affects the first and second 

 pre-molars, seldom the third, and is 

 commoner in the lower than in die upper 

 jaw. Fistula is very rare in the molars, 

 because their roots are protected by thick masses of muscle, and in 

 the upper jaw project into the superior maxillary sinus. Despite 

 these facts, such fistula? do occur. They open into the superior 

 maxillary sinus or into the nostril, producing empyema of the sinus 

 with chronic nasal discharge, which has the peculiarly offensive 

 smell of alveolar periostitis. 



In dogs, dental fistulse originate most frequently from the upper 

 molars. The outer opening is usually near the lower eyelid, and 

 might be mistaken for that of a lachrymal fistula, were it not that 

 probing shows it to communicate with a molar tooth. For a descrip- 



Fig. 303. — Periostitis areo- 

 laris ossificans of the third 

 molar (horse). 



