Page 321 - My FlipBook

USE OF AMALGAM. 319

amalgamation appears to be complete the mass is transferred to the
hand and kneaded, then pressed into a ball. It is next enclosed in
stout muslin, or China silk as recommended by Dr. C. E. Kells, Jr.,
and the surplus mercury expressed by wringing ; when no more mer-
cury appears through the muslin, the button is removed : it should break
with a clean, white fracture surface.
Another method of mixing the filings and mercury is that of Fletcher.
Filings and mercury are placed in a long glass tube which is shaken vio-
lently until amalgamation is complete.
The Packing Operation.—Several devices have been invented for
the pui'pose of carrying the amalgam to the tooth cavity, one of the

Fig. 283.

most simple being sliown in Fig, 283, and another in Fig. 284. An-
other excellent instrument is shown in Fig. 285, one end having ser-

FlG

rated points which engage the soft amalgam, the other a plugger
head.
Numerous methods have been advanced and advocated for the pack-
ing operation. The one commonly followed is that of burnishing the
amalgam. This has been shown by Dr. Black to weaken the mass. A
small piece, rarely more than a cube of i in. side, is carried to the deep-
est and most inaccessible recess of the cavity and pressed against its
walls by tapping, burnishing, or uniform pressure. Dr. Flagg's method
is by tapping. Each successive piece of amalgam is tapped upon by the
packing instruments until it combines with its predecessor and is per-
fectly adapted to the cavity walls. The set of instruments shown in
Fig. 286 are those by which this process is accomplished—Nos. 30-34
being packing instruments, while the others are shapers.