Page 275 - My FlipBook

EXPOSED PULPS. 271

This preparation is better applied perfectly dry,
beneath a lead cap, which should completely close
the cavity. Any other material that would mix as
readily with the arsenic, without being soluble, and

that would not induce irritation when in contact with
the pulp, would be quite as good for this purpose as
charcoal. Irritating gases generated in a tightly
closed cavity, are absorbed by charcoal.
Cobalt, in which the active principle is arsenic, has
been extensively used for destroying pulps; but it
is in no respect superior, and in some respects it is
probably inferior, to the preparation of charcoal and

arsenic : it is applied in the same manner.
The length of time the preparation should remain
in the tooth, will be determined from the condition of
the pulp when it is applied, the age of the patient,
the vascularity of the dentine, the susceptibility of
the patient to the influence of arsenic, and like cir-
cumstances. It will usually be from three to twenty-
four hours. In some cases, a very small particle will
thoroughly accomplish the work; while in others, a
much larger quantity may remain in contact with the
pulp even for a much longer time, without producing

more than a superficial result. And cases occasion-
ally occur, in which it seems almost impossible to
destroy the vitality of a pulp with arsenic. A case
is on record, in which the pulp was first fairly exposed