DENTIGEROUS CYSTS IN THE TEMPORAL REGION. 7 



or less high on the free portion of the ear, it awakens suspicion of 

 necrosis of the conchal cartilage, and may be mistaken for that at the 

 first glance, but palpation of the parts and exploration of the sinus 

 generally settle the question. 



What is the prognosis in these lesions ? I have already said they 

 persist for long periods, even for years, I will add that they are very 

 rebellious to ordinary treatment. The lesion, whether only a swell- 

 ing or a sinus, depreciates the value of the animal. When there is 

 discharge of pus this fouls the region of the wound, and the parts 

 often emit a foetid odour, noticeable on first entering the stable. You 

 have seen that complications sometimes result. Finally, if interven- 

 tion is usually followed by success, it may also involve accidents of the 

 most serious character. 



The treatment formerly recommended included puncture of the 

 cyst or slitting up the fistula, and caustic injections or cauterisation 

 of the walls of the cyst. These methods are insufficient. Cure can 

 only be effected by removing the tooth and destroying the wall of the 

 cyst. 



As a rule the operation is simple and without danger. The horse 

 being cast, the bridle is removed and the head extended. The parts 

 having been prepared, the fistula is laid open or the swelling incised 

 in the form of a cross, and the tooth exposed b}- reflecting the flaps. 

 The attachment is often slight, or the tooth may be loose. It is 

 easily removed with strong forceps or with special tooth forceps, the 

 cyst being afterwards curetted. When it is deeply seated, and the 

 operator is unable to grasp the crown, it may be loosened by means 

 of a chisel and mallet, but cases occur where, in order to free it, a 

 groove must be formed around the tooth by means of a narrow-bladed 

 gouge. It is always necessary to proceed cautiously, avoiding vio- 

 lence, on account of the risk of fracturing the skull and injuring the 

 meninges and brain. All possible antiseptic precautions should be 

 observed. Even when properly carried out the operation may be 

 followed by various complications, by necrosis of a portion of the 

 alveolar wall, bruised during extraction, by fracture of the tympanum 

 (if the tooth abuts on the middle ear), or, if the deep portion is in 

 contact with the dura mater, by meningo-encephalitis. 



When intervention is considered dangerous, it is better to refrain 

 altogether from interfering with the tooth, rather than risk a fatal 

 accident. The only case in which a cranial tooth should be touched 

 is when it produces grave symptoms in consequence of its pressing on 

 the brain. 



