272 



ADVENTITIOUS TEETH. 



in horses and oxen has been compiled by Morot, and in the dog by 

 Sussdorf. 



Excess teeth seldom cause trouble until, by continued unopposed 

 growth, they come in contact with and wound soft tissues. Roll 

 and Dieckerhoff saw cases where a tooth in the lower jaw had 

 become so long as finally to penetrate the opposite bone. The nasal 

 cavity may even be pierced, and an offensive discharge produced. 

 Moller records two such cases. Supernumerary molars, when on 

 the inside of the row, are apt to wound the tongue, and, when on 

 the outside, the cheek. Walther speaks of two accessory molars 

 in the horse which appeared, one on the inner side of each of the 

 third upper molars. The horse had difficulty in chewing. Moller 

 saw two cases where a supernumerary 

 tooth was present on the inner side of 

 the fourth upper molar (Fig. 273). Both 

 teeth suffered from alveolar periostitis, 

 penetrated the maxillary sinus, and pro- 

 duced chronic nasal discharge. In another 

 case the extra tooth was on the inside 

 of the third pre-molar, and interfered with 

 mastication. 



Treatment consists in removing or short- 

 ening the offending molar. Extraction is 

 difficult where the tooth stands close to 

 another, and therefore cannot be grasped. 

 In these cases it may either be shortened 

 or punched out. Such teeth may be re- 

 moved by using forceps with sufficiently 

 thin jaws to pass between the diseased tooth 

 and its neighbour. In the front of the mouth the two teeth may 

 sometimes be thrust asunder with a strong chisel. 



Fig. 273. — Supernumerary 

 tooth (horse). 



IRREGULARITIES IN REPLACEMENT OP THE TEETH. 



Occasionally the milk teeth remain fixed in position, and cause 

 the permanent teeth to grow irregularly. Such milk teeth may be 

 removed with ordinary forceps, though Gunther's are preferable 

 (Fig. 298). It should be noted that the milk tooth is always in 

 front, the permanent behind. The incisor teeth are sometimes 

 absent in dogs, especially in such as have suffered from severe attacks 

 of some infectious disease during very early life. It seems possible 

 that under such circumstances the germ of the permanent teeth 



