Page 150 - My FlipBook

146 THE TECHNICAL PROCEDURES IN FILLING TEETH.

in the anatomy.* Difficulty of this kind should not occur
except in abnormal cases, and when they do, it is generally
because the floors of the pulp chambers have been mutilated
with burs, and the openings of the canals filled with chips.
This should never be done ; burs should not be used in the floor
of the pulp chamber.
No specific directions can be given for abnormal cases. When
the pulp chamber is filled with secondary deposits, the effort
should be directed to the removal of these, preserving the out-
lines of the pulp chamber. When the pulp chamber is much
narrowed by secondary dentin deposited upon its walls, the
openings into the canals should be found before any cutting is
done, and then the cutting carefully directed to straightening
them. In most instances this is done best with the barbed
broach. All small tortuous canals should be enlarged and
straightened with the barbed broach. To do this, cause the
The
broach to enter the canal as far as possible and withdraw it.
barbs will impinge upon the walls and cut away the dentin.
Repeat this, pressing the broach in a direction that will tend to
straighten the canal. By repetitions of the movement, the canal
that can be entered by the smallest broach can soon be enlarged
sufficiently for filling. Generally partial occlusions of canals are
confined to or near their pulpal ends, and where this has been
straightened up, the broach will pass to the apex. In elderly
people certain canals are often too small for successful cleaning
and filling. In cases in which there has been much wearing
away of the teeth, the pulp chambers and the pulpal ends of the
root canals are apt to be much narrowed by secondary dentin.
This applies to all of the teeth in the mouth, i. e., to any that
have, from any cause, not been worn away the same as those
that are worn.
When the root canals have been cleaned, it is generally neces-
sary that a dressing be laid in the canals and the cavity sealed
with a gutta-percha filling until a future time. For this purpose
a wisp of cotton should be formed with its fibers mostly parallel,
and the end of this caught with the point of the broach with the
thumb and finger of the left hand and the broach rotated with
the right hand, while the fingers of the left roll the cotton on its
* Black's Dental Anatomy. For upper molars, paragraphs 173 to 178 inclusive; for
lower molars, paragraphs 180 to 185 inclusive, to which the reader is referred.