338 OPERATIONS ON THE DIGESTIVE APPARATUS. 



in animals advanced in age, the tooth might be fractured or dis- 

 located; or again, the operator himself might be injured by the 

 instrument, when, suddenly displaced by a movement of the ani- 

 mal, the assistant knocks against it." 



It was to remedy this objection that Brogniez invented his 

 odontritor (Fig. 341), an instrument which carries on one end a 

 blade sharpened on both edges, and on the other is hollowed out, 

 in order to allow the play of a rod through one-half of the length 

 of the instrument. This rod is provided with a transversal handle, 

 which also acts as a hammer, by which the blow is carried against 

 the sharp edges of the tooth. 



When the odontritor is used, it is not necessary to use a spec- 

 ulum to open the mouth, the holding of the tongue out of the 

 mouth being sufficient. The operator, holding the instrument 

 with the left hand, places the anterior sharp edge against the j^ro- 

 jecting portion of the tooth, and holding the rod by the handle 

 full in his right hand, moves it to and fro, striking at the j)roper 

 points as he moves it. This operation is repeated on both jaws 

 until all the sharper edges of the teeth have been cut off, and is 

 completed by passing the rasp over the dental plates, as is done 

 when the teeth are not too sharp. 



Several modifications have been made in the conformation of 

 the odontritor, but that of Prange is probably the best (Fig. 342) 

 It consists in ha%ing three blades, which may be changed at will 

 and which vary in the form and disposition of their cutting edges. 

 This instrument is considered superior to that of Brogniez, and 

 is thought to work to better advantage when the elevation of the 

 tooth is well marked. 



The odontritor answers perfectly for leveling the molars when 

 the projections are not excessively developed, or do not offer too 

 great resistance to the action of the blade. But when an entire 

 tooth projects above the general level, the odontritor ceases to be 

 of any advantage, and it becomes necessary to perform the resec- 

 tion of the tooth, consisting in the removal of all that portion of 

 it which rises above the level of the general dental surface. 



To Brogniez is due again the first instrument invented for the 

 performance of this operation in the chisel odontritor (Fig. 343). 

 This is composed of two rods, one of them having at one end, like 

 the ordinary odontritor, a frame of sufficient dimensions to allow 

 the entire molar to pass through it, and on the anterior border of 



