Page 37 - My FlipBook

FORMATION OF CAVITY BORDERS.

perative to remove the corner. Having determined not to do so, sup-
pose that the operator proceeds to pack his gold. Reaching the weak
spot, he abandons the mallet and uses hand-pressure. In spite of this
precaution, a crack suddenly appears along the line of cleavage. The
corner should be removed at once, whether the tooth be healthy or
otherwise.
To the above state that an examina-
emphasize arguments, I may
tion of my records shows that I have filled hundreds of such teeth in
the manner here advised, and that in two instances have the
only
corners broken away afterward. In both cases the contour was restored
without removal of the I have also a few times repaired
filling.
broken corners without the where the
removing original filling, pa-
tients had been in other hands before coming to me.
The economist of tooth-substance frequently makes a mistake in
forming cavities in the approximal surfaces of molars or bicuspids.
FIG. 40. FIG. 41. FIG. 42. FIG. 43. FIG. 44.

as is shown in the as indi-
In such a cavity Fig. 40, he shapes cavity
cated by the heavy line. Operating between separated teeth, with
the little space which we usually have, it is plain that he is at a great
disadvantage as soon as his filling is half completed. He is then
obliged to fill places which it is almost impossible for him to see. It
would be much better to extend the border to one or both of the
dotted lines, as might be required to gain ready access to the cavity
at all parts.
surfaces of molars no directions are
In the masticating special
necessary, beyond advising the use of a rose-bur along the sulci, large
enough to allow the entrance of a plugger if gold is to be inserted,
and larger still where amalgam is to be used. It is a mistake to cut
out sulci with small burs, and then fill with amalgam. The opening
all the line should admit a small ball-burnisher, so that in pack-
along
ing the amalgam the mercury may be thoroughly expressed. Many
have failed because of burs having been used
amalgam fillings tiny
at the extremities of the sulci, so that when placing the amalgam these
points were improperly filled, either with material having an excess
of mercury, which on that account has never set, or with an insufficient
or
quantity dragged or wiped into the crevice with the cotton, spunk,