VE TERINA RY DENTAL SUR GER T. 237 



pulp would not be injured thereby, and especially 

 from the lateral walls and the orifice. 



In removing the decomposed dentine such instru- 

 ments should be selected as would seem best adapted 

 to the purpose. 



In cutting, the direction should be from the near- 

 est point of pulp exposure toward the orifice of the 

 cavity. 



In removing decomposed dentine we must not 

 forget that the cavity must be so formed as to retain 

 the filling when properly introduced. To do this it 

 is most always necessary to remove more or less 

 solid dentine to secure suitable retaining points. 



" In large cavities "where one side of the tooth is 

 weak, places must be selected for making retaining 

 points that will least affect the weak point." (Taft.) 



There are several ways of forming retaining 

 points. Under-cutting and grooving is practiced by 

 some, others preferring to drill little holes or pits 

 into the dentine, these taking effect in different direc- 

 tions. 



After the cavity is formed and before introducing 

 the filling, it must be thoroughly dried with bibulous 

 paper and the warm air blow pipe. 



This instrument is made of a small blow pipe, 

 with a cylinder about two inches from the point. 

 This cylinder is made of some heavy metal, so as to 

 retain heat. On the other end is an india-rubber ball. 



