Page 324 - My FlipBook

320 PIVOT TEETH.

the tooth in plaster of Paris; set the pivot in its
fill round this with fragments
proper position in it ;
of gold plate, and put on solder and borax ; heat up
with a blow-pipe, and draw the solder to the bottom
of the cavity. Another method, sufficient for all
practical purposes, is 5 to set the pivot in place, and
pack round it a stiff amalgam of gold and mercury,

evaporate the mercury by heat. A better method
than any of these is, to have teeth manufactured with

a platinum tube inserted, into which the pivot can be
soldered. Pivots may also be attached to the ordi-
nary plate teeth.
For attaching the metal pivot to the root, it is
sometimes fitted tightly to the canal, and introduced
into it without any other substance. This is object-
ionable, on account of the wearing of the root, certain
to take place, if there is the least jarring or moving
of the crown. To obviate this, various methods
have been devised; one of which is, to wind floss

silk about the pivot before introducing it; but this
soon becomes offensive, and requires frequent re-

newal. Another method is, to introduce a piece of
wood into the root, and drill through it for the re-
ception of the pivot, which is squared and roughened
—squared to prevent it from turning round, and
roughened to secure it from drawing out. But if it
is desirable to remove the tooth occasionally, the
pivot should not be barbed.