Page 249 - My FlipBook

USE OF RUBBER DAM. 247
and kept in position by the left index finger, a mirror, or a cheek-
holder.
An important preliminary to the application of a napkin to these
positions is that the saliva ejector be first placed in action and that the
surfiices of the gum and cheek be wiped to dryness, to cause the napkin
to cling to the surface. If the surfaces are covered with mucus and
at the same time are Avetted with saliva, the napkin easily becomes
displaced.
For the inner surface of the lower teeth a considerable fold of cot-
tonoid or similar substance laid beneath the tongue materially prevents
access of saliva here, and also, by preventing the contact of the tongue
with the teeth, lessens the opportunity for the access of moisture by
capillary attraction betAveen the tongue and the teeth under treatment.
In instances where the form of the parts permits, the fold of cottonoid or
of linen may be retained in place by a dam
Fig. 220.
clamp upon any adjacent posterior tooth.
For the medication of cavities where it is
important to confine the remedy to the
tooth ; in short operations, such as temporary
stoppings, and particularly for the simpler

Fk;. '219.

The Deiihaiii shield. 'shield in use

cases of children, the Denham coffer-dam shields shown in Figs. 219,
220 are of much advantage, more particularly for the lower teeth.
AVith the.se the ejector forms a valuable aid.

NAUSEA.
The contact of rubber dam with the tongue and the contiguous parts,
the presence of napkins', and the touch of the fingers to the oral surfaces
frequently excites nausea. With some persons this kind of distress is
extreme and produces simulation of faintness and nervousness. This
condition may generally be relieved by the use of aqua camphora, a few
drachms being used as a gargle to the mouth and the throat. When
indications of faintness appear a drachm may be swallowed with imme-
diate benefit.
In case excessive nausea is occasioned by the contact of the appli-