Page 49 - My FlipBook

THE RUBBER DAM. 45

the two hands are simply inverted, so that the thumb of the left
is on the occlusal side of the rubber and the thumb of the right
is on the lingual side. In e\ery other way the grasp is the
same. This is suited to placing the rubber on the lower teeth
of the left side of the mouth as far back as the second bicuspid;
the operator standing on the right and passing the left hand
around the head.
The fourth grasp is a complete inversion of the first. In
this the thumbs are both placed on the gingival side of the rub-
ber, and both forefingers on the occlusal side. The rubber is
grasped with the thumbs opposite the first joint of the forefin-
gers, or thereabouts. The ends of the forefingers come together
over the hole to be used, not directly end to end, but in the
form of a letter V, the finger-ends forming the angle. The
rubber is now stretched so as to open the hole slightly while the
finger-ends are close against its margins. Then it is carried
over the tooth, stretching the rubber sufficiently by spreading
the fingers apart, made to pass the contact points between the
teeth one after the other by a slight sawing motion, and the
finger-ends carried hard against the gingivae, one on the buccal
side and one on the lingual side of the tooth. Then the grasp
of the thumbs is released while maintaining the position of the
fingers and the rubber allowed to draw around the tooth. If
the rubber is felt to close on the finger-ends, which it will often
do, and fail to close on the tooth, make a slight oscillating
motion of the fingers which will allow it to slip past them and
hug to the tooth before removing the fingers. The rubber is
now gras])ed anew and in the same way to be passed over the
next tooth, being careful to place the finger-ends very close on
either side of the hole to be used in each instance.
This grasp is i)articularly suited to the upper bicuspids and
first molars, the operator standing partially behind and above
the patient. For this the head of the patient should be thrown
well backward. Often, also, this grasp w ill be very convenient
for placing the rubber on the lower bicuspids and first molars,
the operator standing to the right and in front of the patient.
For this position the head of the patient shoukl be ujiright.
The fifth grasp is used especially for placing the dam on
the second and third molars, or where it is necessary to reach
far back into the mouth. In this the dam is first taken between