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84 THE TECHNICAL PROCEDI^KES IN FILLING TEETH.

the purpose of learniiig the points to be made by this sense.
These are: first, the ability to feel the position of the distal
margin of the hole in the rubber on the fingers ; and, second, by
the sense of touch, to bring this over the distal edge of the bow
of the clamp. This may readily be made to sna]5 over the bow
of the clamp so that it is readily felt and heard. Then the
finger on the lingual will feel its way to the lingual foot of the
clamp and hold that position while the finger on the buccal side
slides to the buccal foot of the clamp. Then release the rubber
with the fingers and complete the operation as directed below.
In other words, when the rubber has passed to the distal of the
clamp, a sweep of one finger on the lingual to the gums, then
sweep the other to the buccal over the bow of the clamp follow-
ing its curvature, completes this part of the movement. Then,
while the fingers are held against each foot of the clamp, the
rubber dam is released with the thumbs. Figure 83. As the
rubber is felt to draw on the fingers, a little oscillating movement
is made, which allows the rubber to close around the neck of the
tooth under the jaws of the clamp. This is generalh' done easily
and quickly when the particular relation of the fingers to the
hole in the dam is appreciated. After this starting point has
been secured, it is not very difficult to secure the rubber over the
teeth mesial to it. When the rubl)er dam has been placed in this
way on a second molar, the rubber may catch on the cusps of
the third molar and require to be pulled forward into position
between the teeth; or it may refuse to enter the contact between
the teeth sufficiently to exclude moisture. Often it may be teased
into place by a pellet of cotton in the foil pliers. If this does
not succeed ])rom])tly, a ligature should be thrown around the
clamp over the rul)ber dam, and with this the rubber is readily
drawn into position between the teeth.
In the upper jaw the most serious difficulty met with in
throwing the rul)ber over the bow of the clamp placed on the
third molar is the interference of the ramus of the lower jaw,
which comes forward when the mouth is ojiened wide and does
not leave room for the finger to pass over to the Imccal side. This
difficulty may be seen when the clamp is applied. The patient
should be instructed lo close the teeth lightly on the ojicrator's
fingers at a word while the operator's finger passes that point.
This clears the way for the finger to pass easily. As these move-
ments are directed entirely liy the sense of touch, the closing of
the mouth, or the la])piug of the rubber over the fingers is of no
consequence.