Page 156 - My FlipBook

152 FILLING TEETH.

during absolute dryness, and that this will soon
return, and then the cavity will be no dryer than it
could have been made with good cotton or paper.

Admitting this, perfect dryness will remain long
enough for the introduction of the rilling. And if
this is facilitated by absolute dryness, and a better
adaptation and attachment obtained, then it is de-
sirable to obtain that condition.
It has already been remarked that perfect dryness
can not be obtained with cotton or paper. To warm
these on a hot metallic plate, after being wrapped on

the instrument, will very much increase their effi-
ciency in removing moisture. Asbestos wrapped on a
small bulb-pointed instrument, and heated, is very
good for drying out cavities ; with it, perfect dryness
can be obtained, as it can be reheated and applied
as often as necessary. To prepare this, select a
proper-sized bulb-pointed instrument; a worn-out bur
drill answers well ; and fold over its fibers of asbestos,
passing them a little way beyond the bulb on the
shaft of the instrument, and there binding them
firmly on with fine platinum wire ; and the instru-

ment is ready for use. Another method of obtaining
perfect dryness—one that is very certain in its

result—is to throw a jet of warm air into the cavity.
This is accomplished by a little instrument, simple
in structure and easily used. (Fig. 43.) It consists