204 



ANIMAL DENTISTRY. 



with the bitting rigging of a driving horse. In the treat- 

 ment of eye afifection their extraction is particularly advis- 

 able, owing to the popular prejudice against them. 



They are difficult to extract without fracture because 

 their location prevents direct outward traction and because 

 of the impossibility of perfectly immobilizing the head and 

 especially the lower jaw. Their removal is accomplished by 

 first disturbing their implantation with the wolf tooth sep- 

 arator (Fig. 93) prior to the application of outward traction 

 with the forceps, or with the separator alone. 



Fig. 143. 

 Supernumerary Incisors of a 6- Year-Old Gelding. 



SUPERNUMERARY TEETH. 



Definition — Teeth existing in excess of the normal num- 

 ber in any of the arcades, are designated as supernumerary. 

 They must be dififerentiated from wolf teeth, which are nor- 

 mal structure and from persisting temporary teeth, due to 

 displacement of the permanent tooth germ. 



Etiology — The supernumerary teeth result from the pro- 

 jection of more than one stalk from the common enamel 

 germ. This occurrence is frequent if not universal, but un- 

 der norrnal development, all the stalks degenerate as a chief 

 one predominates. Whenever two or more keep pace with 

 one another until tooth development is well advanced, the 



