About six years ago I read a paper before the Syracuse Dental Society
on the subject, "Oxy. Phosphate," in which my main object was to
bring forward the idea of its use as anchorage for amalgam fillings
in particular. After the experience I have had with the method, I
have nothing to retract, but can reiterate with emphasis every word
said then. This, now, is no new untried thing I bring before you. For
the last two years it has been talked of more or less throughout the
country. I conceived the idea early in 1884 when a lady came to me for
treatment in whose mouth were four teeth which two years previously
she had been told were beyond saving, but had neglected having them
extracted on account of the dread of the operation. I treated three of
these teeth and filled the roots, but could think of nothing that would
be retained in the crown but cement. I wondered if amalgam would stick
to cement as the cement does to tooth structure. I tried it, and was
successful, and those three fillings are in to-day and can be produced
at any time.
The good results attending its use with amalgam, suggested at once
numerous uses to which it might be put, as: anchorage for gold,
foundation for any other filling at one operation, lining for thin
walls when objectionable color of filling material could show through,
cementing fillings which had fallen out or loosened intact, last to
place temporarily or otherwise. As an anchorage, its greatest is, I
believe, under amalgam fillings in cases of badly broken down molar
and bicuspid crowns where, on account of excessive decay and nearness
of the pulp, reliable undercut cannot be obtained, and if it could be,
would so weaken what remained of the crown as to deprive it of strength
to carry the filling. It is especially useful in molars where the
buccal surface and a half or more of the grinding surface is gone, in
bicuspids whose proximate surfaces are gone with a large share of the
grinding, so that the opening of the cavity is the full size of the
circumference of the tooth and the remaining walls thin. It is
astonishing how many of these latter cases can be shaped and contoured
with amalgam without a particle of the amalgam being in sight after the
work is finished. If in an anterior proximal filling proper contouring
make it necessary for some of the amalgam to show, the anchorage may
be thoroughly relied on to permit of cutting out a small portion and
facing with gold. The shading of the thin walls by the amalgam is
absolutely prevented by the cement. I have in my own mouth a molar in
which the filling was loosened by mastication five times on account of
the cavity being one of the kind where reliable anchorage could not be
obtained. The pulp finally became exposed from frequent cutting away of
tooth structure, and the sixth filling was anchored by taking advantage
of the pulp chamber, or a portion of it. To use cement as anchorage for
amalgam, this is the process: Mix the amalgam according to your custom;
place on a slab for mixing cement a small quantity of the liquid and
powder ready to mix; then, the cavity being prepared, dry it thoroughly
and keep it so while mixing the cement. This being done, place a small
amount in the cavity, and at once upon it place a piece of amalgam,
which should be so manipulated with the instrument suited to the size
and shape of cavity as to force the cement under the amalgam all over
the floor of the cavity. Care should be taken to not force the cement
entirely to the cervical edge in proximal cavities, and any excess
of cement used should be worked out at a point easy of access. By
this time the cement is hard enough to be easily chipped off whenever
it has been forced beyond the inner edge of the enamel. The filling
with amalgam is proceeded with and finished in the usual manner. It
is essential that the cement should not be smeared over the edges of
the cavity, but carefully worked all over the dentine, closing the
mouths of the tubuli, allowing the enamel edge free for contact with
the amalgam. The edges of such a filling are better, and remain better
than those of the ordinary filling, for the reason, I believe, that the
cement controls, or at any rate lessens, the spheroidal tendency in
the amalgam. In very deep cavities it is well to work into the cement
a piece of hardened amalgam before inserting the fresh, as it lessens
the amount of cement necessary, and also of the amalgam, and again
prevents the tendency to spheroid. Proximal cavities in children's
teeth are very easily filled with amalgam by this method, and without
causing pain in cutting tooth structure.
We now come to the use of cements as anchorage for gold. With this
material it has a smaller field of application, and in my hands does
not yield as good results as in the use of amalgam. I believe that
Dr. F. D. Nellis, of Syracuse, New York, was the first to conceive
the idea and use the cement as an anchorage for gold. It is useful in
teeth having very shallow cavities, and in those cases where, while it
is desirable to use gold, the edges chip or shale off at every attempt
to make the cavity retentive. The method of use is as follows: The
rubber dam, of course, is used. The cavity being ready, a small amount
of cement is mixed and placed in it. On the cement put a cylinder of
gold large enough to cover the floor of the cavity. Work the gold
into the cement, at the same time working the latter all over the
cavity. Trim cement from edges and proceed with the filling, making a
mechanical anchorage of the gold with that anchored by the cement. Foil
or pellet may be used in place of cylinder, and it may be cohesive or
not, and the filling finished with soft or cohesive gold, but I think
the best results are obtained by using soft cylinder over the cement,
continuing with the same and finishing with a few strips of annealed
foil. A very good way is to proceed to fill the cavity with gold the
same as if cement were not to be used for anchorage, holding the gold
in place with another instrument, and when sufficient has been inserted
to nicely take the form of the cavity, to take out, place a little
cement in the cavity, then force the gold back to place, and after
waiting a minute or two for the setting, go on and finish the filling.
It is not necessary in this work to confine oneself to the use of the
phosphate of zinc cement. In restoring color to very dark pulpless
teeth, and wherever extra whiteness is desired, the oxychloride may
be used with advantage, but must not be relied upon for strength like
the oxyphosphate. In shading, I get the best general results from the
yellow shade of the latter. Pulpless teeth generally have a bluish
tinge, and yellow seems to neutralize it very effectually. In regard
to the effect of oxyphosphate in deep cavities in teeth with living
pulps, it does not seem necessary for me to say much here, since the
subject has long been worn threadbare by the profession. However, it
must be borne in mind that here is a difference. The cement in use I
have described is sealed away from the fluids of the mouth and does not
have the same effect as when being disintegrated by those fluids. It
remains a perfectly inert substance so long as moisture is kept from
it, and has the same use in the floor of the cavity as the varnish so
often recommended for closing the tubuli of the dentine to prevent
ingress of moisture from that direction. In such cases it is a very
simple matter to touch the bottom of the cavity with liquid gutta
percha before using the cement. In cases of exposure where capping is
desired, cap according to your custom and then proceed as described.
When extirpation is resorted to, I fill root and pulp chamber with
gutta percha.