REPULSION OF TEETH 13 



its centre, by using a trephine not exceeding 2 to 2.5 cm. in 

 diameter and cautiously sawing through the compact layer 

 of the external plate only, removing the cancellated tissue 

 with the gouge and extending the opening in the desired 

 direction after the outlines of the tooth fang have been 

 clearly determined. If an adjoining fang is wounded, the 

 tooth should be removed as it will not heal but will result 

 in a permanent tooth fistula. 



Fracture of the alveolar walls of the inferior maxilla 

 may occur during the removal of the external alveolar plate 

 with the chisel or the repulsion of the tooth with the 

 punch. The first is to be averted by care in having the 

 chisel sharp, by observing the precaution of making a 

 bevelled cut through the bone, by using only moderate 

 blows and driving the instrument alternately for a short 

 distance on each side. The second danger of extensive 

 fracture may be averted by being cautious to see after each 

 stroke on the punch that it has not slipped inward along 

 the ;^median side of the tooth, pressing the internal plate 

 away from the tooth and tending to produce a longitudinal 

 fracture nearly or quite as long as the dental arcade. 

 Careful digital exploration in the mouth may discover this 

 fracture while still "simple ", but a stroke or two more will 

 convert it into the very much more serious "compound " 

 fracture opening into the oral cavity. Keeping one hand 

 constantly in the mouth at the point of impact is always 

 desirable as a precautionary measure. 



Transverse division of the tooth while yet in situ by 

 means of the bone chisel, as above described, is a great 

 safeguard against fracture of the jaw by lessening the force 

 required in repulsion and by the removal of the tapering 

 fang, which then leaves a more secure base for the punch 

 to act upon. It should never be forgotten that the impact 

 from the punch must always be as nearly parallel to the 

 long axis of the tooth as is possible. 



