Page 53 - My FlipBook

THE RUBBER DAM. 49

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 so very difficult to secure the rubber over the
teeth mesial to it.
Passing the contact with ligatures should be done with much
care, for if it is allowed to snap onto the gums it will often induce
considerable pain and do the patient a real injury by cutting into
the tissues. To avoid this, always catch the ligature very close
to the tooth on both the buccal and lingual sides. This will pre-
vent that forcible snap onto the sensitive tissues that is sure to
occur if this precaution is not observed.
In manv cases a ligature must be tied over the rubber to hold
it in place, or to force the gums sufficiently to the gingival to
expose the gingival margin of the cavity. In doing this the lig-
ature should be carefully forced close to the gingival line and
tightly drawn with a surgeon's knot. Generally it is not neces-
sary to tie ligatures on every tooth over which the dam is placed.
Often when ligatures seem necessary, if the rubber is just drawn
well down the ligature may be at once removed and the rubber
will remain in position. Ligatures are often painful and when
the results can be well accomplished without them they should
not be used.
Often there will be difficulty in adjusting the ligature to the
lingual side of the incisors with the unaided fingers. The shape
of the lingual surface causes it to slip off. In these cases the
ligature should be thrown loosely around the tooth and the first
half of the knot formed, but before it is drawn up the flat-curved
burnisher should be passed to the lingual of the tooth inside the
loop of the ligature, and carried to the gingival line and so
inclined that when the ligature is drawn with the other hand it
will be guided to the right position. Then the burnisher may be
removed and the knot closed. This burnisher is useful in many
positions as an aid in the adjustment of ligatures.
In tying ligatures about the teeth, the first half of a surgeon's
knot should first be formed and tightly drawn. In doing this
the ligature should be grasped as close to the knot as practicable,
and held close against the teeth, both to the mesial and to the
distal. If the ligature is over the biduspids or molars catch the
distal end of it over the end of the forefinger of one hand and
force it to the distal while pulling the mesial end with the other
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