100 DISEASES OF THE TEETH. 



the operator grasping the cylinder firmly close to the brass 

 bulb, at the same time employing so much traction as will 

 suffice to keep the chisel at the posterior part of the frame 

 close to the back of the tooth. The tooth being closed in, late- 

 rally by the guards and posteriorly by the passive chisel, the 

 active chisel is then to be brought in contact with the ante- 

 rior part of the tooth. It will thus be seen that the tooth is 

 imprisoned on all sides, and a hammer of about two and a- 

 half pounds weight is to be selected to give the blow with." 



To serve the purpose of Brogniez's ' rabot odontriteur,' Mr 

 Gowing has invented the ' guarded chisel,' drawn at Fig. 53, 

 which is of sufficient width or space to cover the table or 

 upper surface of the molars, and is used with the ' lateral 

 repeller ' shown at Fig. 54. 



" It consists of a solid entire piece of steel. At one end is 

 the handle, which is encased on either side with pieces of 

 wood, retained in their situation by rivets. The other end is 

 shaped into a hook-Like form, flattened and bevelled, with a 

 guard on one side, for the purpose of retaining the instru- 

 ment in its situation, and preventing its being displaced from 

 the tooth. It possesses some of the advantages of the former 

 sliding chisel; but this instrument is not meant to be used 

 by itself; it is intended to prevent the concussion on the 

 jaw, while the operator, with a chisel, strikes off any pro- 

 jecting angle of the tooth/' 



The instrument indicated "by Fig. 55 is Mr Gowing's 'pos- 

 terior repeller,' destined to be used principally for the back 

 or posterior teeth when the 'lateral repeller' cannot be 

 applied. 



EXTKACTION OF TEETH. A'cafious tooth requires to be 

 removed, but there is the great difficulty in extraction, and 

 the broad gap left after it, which deter many anxious to 

 operate. Whenever the fang of a tooth has been diseased, 



