Page 68 - My FlipBook

52 THE TREATMENT OF TEETH
its use causes the gold to work with an added
degree of softness that enables better and more
rapid work to be accomplished, do not agree with
the writer's experience. It certainly thoroughly
anneals the gold without any fear of over- annealing
it. The writer has left both foil and crystal gold on
it for half-an-hour with the current full on (Custer's
electric annealer), and found the gold worked per-
fectly satisfactorily. It is only necessary, however,
to leave the current on till a part of the fireclay
slab glows with the heat, and any one who has
regard for his own comfort, or the well-being of his
bracket-table, will switch off the current as soon as
the requisite heat is produced. These annealers
would be greatly improved if they were larger. If
a dentist works without an assistant at the chair, or
if the assistant is employed in malleting the gold, he
will have to stop to recharge the annealer with gold
several times during the making of a large golji
filling. If the naked flame of a spirit-lamp is used,
it must give off no carbon. The least trace of
carbon deposited on the gold will prevent perfect
cohesion and spoil its working properties.
Methylated spirit seems to vary very much in this
respect, and it is well to test it by placing a sheet of
mica over the flame, and leaving;- it there for ten
minutes. One lot of methylated spirit will be found