Page 227 - My FlipBook

PREPARATORY TO FILLING 211

during its insertion is reduced to a minimum.
Of course a fairly thick varnish should be used.
The writer sees no advantage in the employment
of metal caps for covering arsenical applications,
and preventing pressure ; this is more trouble than
it is worth, and it is easy to seal up the arsenic
without pressure. Temporary gutta-percha should
always be very carefully used, and packed to place
with lateral pressure ; this is the material of all
others that is likely, not only to squeeze out
some of the arsenic, but also to produce pressure
on the pulp. Many operators use Fletcher's arti-
ficial dentine (oxysulphate of zinc) in these cases.
The writer prefers a thin mix of a slow-setting
oxyphosphate cement, and presses it to place with
instruments dipped in vaseline. It should be
sufficiently soft to almost flow to place, so that
absolutely no pressure is exerted on the pulp.
These thinly mixed oxyphosphates set sufficiently
hard for all practical purposes, and are not difficult
to remove. An oxyphosphate or a wool and
varnish covering of an arsenical application is
therefore recommended, with a distinct preference
for the oxyphosphate in many cases. In cases
where the direct application of arsenic to the pulp
is difficult, or very painful, a small hole may be
drilled in the dentine at some convenient place