Page 135 - My FlipBook

APPROXIMAL CA VITIES IN BICUSPIDS. 1 2 1
immovable.
the first pellet Either of these cavities, prepared as indi-
cated, becomes simple, and could be rapidly filled with gold.
In Fig. 129 we have what may be termed a simple approximal
in a It is similar to
cavity bicuspid. Fig. 112, where it is shown in
a central. Its preparation here is different. We no longer need deep
labio- and palato-gingival extensions, nor are we compelled to avoid
labial and palatal grooving. In the bicuspid we
have simply a cavity surrounded by strong walls.
Any antagonizing retaining arrangement will
serve to hold the in The choice,
filling place.
therefore, must depend upon attendant circum-
stances. Where the adjacent tooth is missing,
a moderate groove forming an undercut all
around will prove the simplest and best. Where
there is an adjacent tooth and we must work at
the disadvantage of having the cavity more or less inaccessible, we
may best proceed otherwise. The most universally useful arrange-
ment will be as follows : make a palato-gingival extension, not too
but so as to restrain the
deep, shaped first pellet, as indicated
at a. Make a similar depression toward the crown at the palatal
corner, as seen at b. Connect the two by a fairly deep groove
along the palatal border. A rose bur run around the rest of the
cavity borders, making a general but not deep groove, gives us a
filled. To the
strong cavity readily place gold, begin in the palato-
gingival extension, and having securely anchored the gold at that
point, build along the palatal groove and also along the gingival bor-
der simultaneously, being careful not to advance either too
rapidly,
lest the excess of gold placed at one point make the other inaccessi-
ble. This is a very important factor in the successful of a
filling
bicuspid. It will be seen that by following this plan we finally come
to a point where the labial corner at c must receive attention. Es-
where the labial border of the is at some distance from
pecially cavity
the labial surface proper, any undercutting at this part becomes quite
difficult to fill, and the most
unmanageable point of all would be at c,
so that as we approach this place we must use greater caution. It
must be filled before the gold has been brought so close that we have
inadequate room to reach it ; and yet in packing gold into this corner,
if we at once build it out to the edge of the cavity, we will find it diffi-
cult to fill the hollow which will have been left behind along the sur-
face of the gold. More than likely when we come to polish the filling
caused by an of The
we will find an ugly pit, insufficiency gold.
remedy is simple, but requires patience. Though for the bulk of
we may have been using fairly large pellets, as soon as we
the filling
arrive at this corner we must choose smaller pieces of gold and build