512 DISEASES AND INJURIES OF THE FACIAL REGION. 



inner plate of tlie orbit, that punching is rendered an impos- 

 sibility. I find, however, that the fourth molar is more liable 

 to caries than any of its fellows. This tooth is shorter and 

 thicker in its fang than the others. Its fang is also more 

 deeply imbedded in the sinus than the third and fifth ; more 

 towards the cavity of the nose ; and were it as long as they, it 

 would protrude into the nasal chamber. It has therefore a short 

 thick fang, and its pulp cavities are sooner obliterated by a 

 deposition of dentine. In some five-year-old mouths, I find its 

 pulp cavities quite obliterated. 



The first, second, and even third molars may be withdrawn 

 with the forceps, but they are much more easily removed by 

 punching. The fourth, owing to the thickness of its fang, and 

 the difficulty experienced in fixing the forceps to a worn-down 

 tooth, is only removeable by punching from above. 



I have operated in this manner both upon the upper and 

 lower molars. The operation is very simple. Cast the animal, 

 and trephine, so as to make the opening to correspond to the 

 fang of the diseased tooth, allowing sufficient space above or 

 below the root of the fang — ahove, if the operation be in the 

 upper, and telow, if in the lower jaw — for the introduction of 

 the punch. The punch should be at least an inch in circum- 

 ference at its point, that it may not cut or split the tooth. 



Two or three smart, but not heavy, blows with the hammer 

 are sufficient to dislocate the tooth ; and when this is eff'ected, 

 it may be removed with the smaller molar forceps, or even by 

 the hand. 



The after-treatment is very simple, and consists in frequently 

 washing the cavity with water containing a little carbolic acid 

 or chloride of lime. The elastic syphon is a very useful in- 

 strument for this purpose, the nozzle being introduced into 

 the wound, and the water forced into the cavity. In this 

 manner foreign matters, impacted food, &c. are forced out of the 

 sinus. 



It might be supposed that an opening thus made would 

 remain as a sinus of communication, but in all my cases, where 

 the bones have been healthy, the alveolar cavity has become 

 obliterated ; in the course of about five weeks its sides have 

 approached each other, and the gum over them has become 

 quite hard. 



