292 SYMPTOMS OF ALVEOLAR PERIOSTITIS. 



or root of the tooth. This persists (compare "dental fistula"). In 

 disease of the upper alveoli pyogenic infection sometimes extends 

 into the superior maxillary sinus. Perforation into the nasal cavity 

 may follow disease of the pre-molar alveoli and produce a chronic 

 nasal discharge. Occasionally the alveolar wall becomes necrotic 

 and extensive ostitis ensues. Fig. 287 shows how much a tooth 

 may be displaced. The last molar lay horizontally, and under it a 

 piece of bone the size of a hen's egg had become necrotic. 



The symptoms consist in slow, interrupted, one-sided mastication, 

 rolling of the tongue, slobbering, and dropping food from the mouth. 

 Even from the outside it may be discovered that one or another 

 of the teeth is displaced ; while the cheeks are distended with masses 

 of food. On passing the hand into the mouth, the exact displacement 

 is ascertained. The peculiar, repulsive so-called " carious " smell, 

 especially noticeable in the retained masses of food, is quite 

 characteristic of alveolar periostitis. In dogs the smell, whilst very 

 offensive, is somewhat different from that in horses. Closer examina- 

 tion shows that the gum has receded from the affected tooth, which 

 is so loose as sometimes to be movable by the fingers. It is usually 

 pushed out of line or lies deeper than the others. As might be 

 expected from the direction of their wearing surfaces, the upper 

 molars are generally displaced outwards, the lower inwards. 



In cattle, epileptiform seizures sometimes occur. In chronic 

 cases the animal wastes. In the lower jaw the bone enlarges and 

 fistula forms, indicating the position of the diseased tooth. If the 

 interior of the mouth be illuminated by a mirror, changes in the 

 teeth as well as in the gums may usually be very plainly seen. 



Treatment. Extraction is the only certain method of dealing 

 with alveolar periostitis. This is comparatively easy in old subjects, 

 whether horses or oxen, but may be more difficult in younger 

 animals, especially when the crown of the tooth is broken, as not 

 seldom happens. Several teeth may be simultaneously affected, 

 or one soon after another, and under such conditions the prognosis 

 is less favourable. It may then be a question whether the animal, 

 with its still remaining teeth, can chew sufficient food, and vegetable 

 feeders frequently cannot do so. Punching out the diseased tooth, 

 as adopted in former times, is now only resorted to when the forceps 

 cannot be used owing to the loss of the crown. The operator 

 commences by trephining the jawbone as nearly opposite the root 

 of the affected tooth as possible. The success of the operation 

 depends on the choice of the proper spot. In the upper jaw the 

 landmark is the lower end of the zygomatic ridge of the superior 



