Page 66 - My FlipBook

62 THE TECHNICAL PROCEDURES IN FILLING TEETH.

This completes the use of the round bur, and it is the only use
made of it in excavating cavities. An examination should now
be made with a curved explorer to determine more nearly the
extent of the decay in the dentin. In case no softened dentin
extending laterally under the enamel is found, the rubber dam
should be applied and an inverted cone bur, equal in sizeWith
the last round bur used, should be introduced, and with its
square end the remaining decay should be removed, and the
floor, or pulpal wall of the cavity made flat. Now, with hoe
12-5-6 used as a chisel (straight chisel 10 or binangle chisel
10-6-6 may be substituted), the enamel is chipped away along
the buccal groove as far as it will readily split off". Then an
inverted cone bur, 10 millimeters in diameter, is passed into the
cavity and made to enter the dentin just beneath the dento-
enamel junction toward the buccal groove, and slowly drawn to
the surface of the enamel. It is then entered again at the same
point, and this motion repeated, making cut after cut, following
the line of the groove, until the groove has been opened to a
point where it is sufficiently shallow, or the surface of the enamel
is sufficiently level for a good finish of a filling to be made.
Often it will be necessary to follow this groove to the crest of the
marginal ridge. This done, chip away the mesial and distal
walls of the slot formed, with straight chisel 15 or 20, sufficiently
to remove the inclines of the buccal groove, after which pass a
large inverted cone, or a fissure bur (ito millimeters), through
the slot, and make its floor square and flat, and smooth up the
walls.
A very careful examination should now be made of all parts
of the walls of the cavity. If any softened dentin is found, the
enamel should be chipped from over it with hoe 12-5-6 or chisel
10, the softened area removed and the pulpal wall of the cavity
squared out to the increased area.
The outline of the cavity should now be re-examined to see
whether every part of the margin is sufficiently level to permit a
good finish of the filling when this has been placed, and if irreg-
ularities occur that would prevent a smooth finish, the cavity must
be sufficiently extended to obtain conditions that will allow a
good, smooth finish of all parts of the margin to be made.
The finish of the enamel wall is now to be made by
careful paring or planing with a sharp chisel. So far as possible