Improvements in Artificial Teeth.
Year: 1898

page_text: Date of Application, 12th July, 1898-Accepted, 10th Sept., 1898
.
Improvements in Artificial Teeth.
I, CHARLES ELWOOD FOSTER, of 931, F Street, North West, in the City of Wash-
ington, District of Columbia, United States of America, Lawyer, do hereby declare
the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement: -
It has been common to provide artificial dentures with openings extending to the
rear or labial faces, and to embed in the dentures platina rings or tubes or perforated
disks or plates, so arranged as to receive the stems of pins made of silver or base
metal, which are soldered to the anchoring pieces and thereby secured to the
dentures.
It is of course exceedingly desirable to reduce the amount of platina to be used in
such cases, and it is also desirable to secure as extended a bearing longitudinally as
possible for the pin, thereby to increase the extent of the anchorage. Further it is
desirable to secure the anchoring piece in the denture so that it cannot pull out, and
so that stress upon the same will not have the effect of splitting or flaking off the
porcelain at the back of the teeth.
In order to secure these desirable results and obviate certain defects of prior con-
structions, I make the anchoring piece in the form of a clip as fully set forth herein-
after and as illustrated in the accompanying drawings, in which Fig. 1 is a perspec-
tive view of my improved anchoring piece; Figs. 2, 3 and 4 perspective views
illustrating the same with additional features intended to secure a more extended
bearing for the pin and a better bearing in the body of the denture; Fig. 5 is a
transverse section of a tooth with the anchoring piece, Fig. 1, embedded therein;
Fig. 6 is a section on the line 6-6, Fig. 5; Fig. 7 is a vertical longitudinal section
of a part of a mold illustrating the manner in which the anchoring piece is applied
in the manufacture of the tooth; Fig. 8 is a plan view of the lower mold section ;
Fig. 9 is a view illustrating the manner in which the strips may be cut from which
to form the anchoring pieces or clips; Fig. 10 illustrates a blank made of wire bent
back and forth; and Fig. 11, an end view of the clip made by bending the blank;
Fig. 10.
The anchoring piece A, Fig. 1, is made in the form of a clip from a flat strip or
sheet of metal, or from a wire bent back and forth to form a flat strip, as in Fig. 10,
bent around to an extent exceeding a half circle, Fig. 11. It is necessary that the
clip should exceed a half circle, first, because with less metal than a complete tube it
gives a longer bearing for the pin which is inserted therein and soldered thereto;
and secondly, because it is necessary in the manufacture of teeth to have some
means for supporting the clip while the body is applied in the mold.
For instance in Figs. 7 and 8 which illustrate the mold usually employed, there
are shown two posts 3, 3, (of which there may be any suitable number) projecting
upward from the lower mold section B within the recess X thereof; and which posts
serve to form in the body of the material, which is pressed between the sections of
the mold, the openings x extending to the rear faces thereof. By making the clips
A in extent less than a complete circle but greater than a half circle, I am enabled
with a small amount of metal to apply the clips to the posts 3, 3, and they will

page_text: adhere to the same, so that when the body material is inserted between the sections
B, B¹ of the mold and pressed therein as the sections are brought together the strips
will adhere to the posts and will not be displaced.
If the anchoring pieces were made, as heretofore has sometimes been done, in the
form of a tube they would be objectionable for two reasons. In the first place, the
porcelain shrinks greatly and contracts in baking, and as the tube does not shrink to
a proportionate extent, there is a certain amount of stress upon the porcelain which
tends to cause the same to crack easily under any strain. Secondly, when the
anchoring piece is in the form of a tube, the latter cannot be made of any extended
length, so as to secure an extended longitudinal bearing for the pin, without an
objectionable increase of the cost.
With the anchoring piece made in the form of a clip, consisting of a strip bent to
more than a half circle, but open at one side, the clip may be increased very
materially in length, while employing the same amount of metal which would be
used for making a complete tube shorter in length; and a still greater length of
bearing may be secured by providing the clip with a projection 4 of less than a half
circle extending longitudinally from one end as shown in Fig. 3, and yet without
increasing the weight of metal which would necessarily be employed if the clip was
in the form of a tube of shorter length.
In order to prevent the anchoring piece from drawing out under any stress upon
the pin which is soldered thereto as usual, I prefer to serrate the inner end thereof,
as illustrated in Fig. 4. This permits a portion of the body material to extend into
the serrations around the opening in which the pin is inserted, and these extensions
being in front of the rear end of the clip or anchoring piece will effectually prevent
the same from being drawn out. Still further security may be obtained by providing
the clip at one or both edges with a projection 6.
When the clip is made in the form illustrated in Figs. 1 or 2, it is only necessary
to cut a strip X¹ (Fig. 9) of sufficient width, transversely, and then bend the pieces
severed from the strip to the form shown in Figs. 1 or 2. When it is desirable to
form the anchoring piece with serrations as shown in Fig. 4, the strip is cut first on
a zigzag line 5, Fig. 9, and then on a straight line 8, Fig. 9, the strips thus severed
being then bent up to the shape shown in Fig. 4.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. An anchoring piece for artificial dentures consisting of a plate of flat metal (or
wire bent back and forth) and bent to less than a complete circle with or without
projections 4 and 6 or either of them, substantially as set forth.
2. The anchoring piece less than a complete circle, and serrated at the end
substantially as shown in Fig. 4, combined with and arranged within the opening of
an artificial denture, substantially as set forth.
3. The combination in an artificial denture of the porcelain body portion having a
recess opening toward the lingual side, with an anchoring piece within and extending
partially round said opening, substantially as set forth.
Dated the 12th day of July 1808
PHILIP M. JUSTICE,
Chartered Patent Agent, London,
For the Applicant.