Page 183 - My FlipBook

THK RCBBKR DAM. 75

when the grasp on the rubber has been released, but while it is
still held against the gingiva^ to allow it to close around the tooth.
These are the critical points in placing the rubber dam. If the
definitions given, and the systomatization of the plans of this
work are carefully studied in the beginning, the placing of the
rubber dam will be relieved of much of its difficulty.
In considoi'ing these grasps, the side of the rubber which,
when applied, will be next the gingiva^, is called the gingival side;
and tliat which will be toward the occlusal surfaces of the teeth,
is called the occlusal side. The five ways in which the rubber dam
may be grasped in applying it to teeth in the different positions
in the mouth will be numbered as they are presented. Notice par-
ticularly, that one of the most essential things in grasping the
rubber dam is that the thumb and finger nails shall come against
the labial and lingual surfaces of the tooth to which it is applied.
The first grasp is used when the dam is to be applied to
the upper front teeth. Grasp the rubber between the thumb and
first finger of each hand, with the thumbs on the occlusal side of
the rubber and their ends with the nails touching together imme-
diately over the hole to be first used. The finger-ends should be
on the gingival side of the rubber, midway the balls of the thumbs,
Figure 66. Stretch the rubber a little with the thumbs still touch-
ing end to end. It is especially important in this, and all other
rubber dam grasps, that the nails of the thumbs, or fingers, on
the occlusal side of the rubber be over the margin of the hole to
be used, as seen in Figure 66, so that, in pressing the rubber down
over a tooth, they will carry the actual margin of the hole to the
gingiva?. Also the nails must be in such position that they will be
next to the teeth to hold the margin of the hole more securely in
position while the rubber dam slips under the finger end, or end
of the thumb, in drawing around the neck of the tooth. It is
largely upon the correctness of this particular hold upon the rub-
ber that success in placing it easily and quickly depends. When
grasped in this way, stretch the rubber a little more, and, stand-
ing to the right side in front of the patient, pass the hole over
the upper incisor tooth, the right thumb on the lingual and the
left on the labial side. In doing this, first place the free edge of
the rubber at one side of the hole between the teeth, and, with
a slight sawing motion, force it past the contact on that side;
then stretch it over the tooth and force it past the contact on its
other side in a similar way. Now carry each of the thumb nails
against the gingivae, the one on the labial, the other on the lingual
side. This is the end of the first movement. The position is