Page 72 - My FlipBook

56 THE TREATMENT OF TEETH —

apply to other makes, and is worth remembering.
Another point is, that the thick small squares that
have been alluded to for surfacinsf fillini?s, can be
more satisfactorily annealed on the electric annealer
than in any other way.
The balling up of gold that is so often alluded
to, simply means that the gold refuses to cohere.
This may be due to under, or over, annealing
usually the latter—but given a good make of gold,
and an operator of some experience who is careful in
little things, it is rarely that a piece of gold will "ball-
up." On the other hand, given a careless dentist,
whose foil carriers are smeared with dried varnish
or cliloropercha, the serrations of whose instruments
are rusty or dirty, and who anneals his gold in the
naked flame of a spirit-lamp, the wick of which is
thoroughly charred, or contaminated with the fumes
of the matches used in lighting it, &c., it is not to
be wondered at if he finds it difficult to work co-
hesive gold.
Combination of Cohesive and Non-Cohesive Gold.—

Non-cohesive gold is frequently used for starting
fillings of cohesive gold, either to facilitate this part
of the operation, or to avoid the use of starting
pits. The writer has never been able to under-
stand the prejudice that exists in the minds of
some against starting pits. A starting pit is drilled