Page 51 - My FlipBook

THE RUBBER DAM. 47

In using the fifth grasp, the operator can use the full length
of the forefingers for reaching back into the mouth and yet have
full command of the rubber and readily place it on any tooth
where the contacts can be passed with a sawing motion of the
fingers ; and in ordinary cases it will hold without the aid of a
ligature while passing it over other teeth. Of course, there are
many molar teeth around which the gums are so high that the
rubber can not be passed far enough onto the crown in this way
for it to hold. There are also a good many tooth crowns so
rounded that the dam must be forced actually to the gingival
line and tied down with a ligature or held by a clamp before it
can be induced to remain in place. With these grasps, how-
ever, everything can be done that it is possible to do with the
unaided fingers.
The Use of Ligatures in Adjusting the Rubber Dam.
There are many cases in which the rubber can not be forced
between the contact points of adjoining teeth with the unaided
fingers, and then it must be forced with the ligature. This is
best done by an assistant. However, by careful practice one
may learn to do it successfully alone. The ligature may be used
with any of the five grasps. To accomplish this, wrap the end
of the ligature on the little finger of the left hand and catch a
part of its length in the same grasp with the rubber in the thumb
and finger of the right hand, leaving just sufficient length
between so that the ligature may be tightly drawn by a move-
ment of the little finger on which it is wrapped. Bring this
ligature over the contact to be forced beside the finger, or the
thumb, of the left hand at the same time that the rubber is
stretched over the tooth. Then, by drawing with the little
finger of the left hand and by the grasp with the right, the
ligature is forced through, carrying the rubber before it. To
get just the right length and adjustment of the ligature generally
requires a little maneuvering in each individual case. The
observant operator will see his way clearer and be better able to
avoid difficulties with each failure.
In cases in which considerable force is recjuired to drive the
rubber past the contact the grasp with the fingers is often insuffi-
cient. The ligature will slip in the fingers and the rubber will be
stretched too much, and a general derangement of the position
•