152 ON GUTTA-PERCHA AS A PERMANENT STOPPING. 



gold stopping, and care taken to exclude all 

 moisture, especially blood, during the operation of 

 filling. It should be slightly warmed before intro- 

 duction, and nicely packed and moulded in with 

 warm instruments, the edges being accurately 

 finished ofi*, the surface smoothed, and all super- 

 fluous portions removed. It is best, where the 

 cavity is not very easy of access, to use a piece at 

 first barely sufiicient to fill it, as it is easy to add a 

 small portion afterwards, if necessary, and a super- 

 fluous quantity would only hamper one in one's 

 manipulations, and be troublesome to remove. In 

 finishing off*, the instruments should be made hotter 

 than boiling water, the cement can then be made 

 to adhere thoroughly all round the edges. The 

 forms of instruments for the purpose will readily 

 suggest themselves ; they should be smooth and 

 polished — burnishers, in fact; rounded, wedge- 

 shaped, thin and flat, straight, right-angled, and 

 oblique. The cases where it wiU be found most 

 useful, are cavities which are in sight, which are 

 sensitive to pressure, heat, or cold — those the walls 

 of which are thin and weak, which are in relation 

 with an artificial piece, &c. ; and also where the pulp 

 is exposed, should it be deemed advisable to have 

 recourse to stopping at aU, as it would be easy, by 

 careful manipulation, or by the use of a metal cap, 

 to prevent the cement from touching the nerve, and 

 at the same time to seal it completely round the 



