IMPROVEMENTS IN ARTIFICIAL TEETH AND IN MOULDS FOR FORMING THE SAME
Year: 1864

page_text: LETTERS PATENT to George Davies, of No. 1, Serle Street, Lincoln's Inn,
in the County of Middlesex, and No. 28, St. Enoch Square, in the City
of Glasgow, Civil Engineer and Patent Agent, for the Invention of
LETTERS PATENT to George Davies, of No. 1, Serle Street, Lincoln's Inn,
in the County of Middlesex, and No. 28, St. Enoch Square, in the City
of Glasgow, Civil Engineer and Patent Agent, for the Invention of
"IMPROVEMENTS IN ARTIFICIAL TEETH AND IN MOULDS FOR FORMING THE
SAME." A communication from abroad by John Terrel and Joseph
Stulb, both of Philadelphia, Pennsylvania, in the United States of
America.
Sealed the 22nd November 1864, and dated the 31st May 1864.
PROVISIONAL SPECIFICATION left by the said George Davies at the
Office of the Commissioners of Patents, with his Petition, on the 31st
May 1864.
I, GEORGE DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County
of Middlesex, and No. 28, St. Enoch Square, in the City of Glasgow, Civil
Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN ARTIFICIAL TEETH AND IN MOULDS FOR FORMING
THE SAME," (a communication to me from abroad by John Terrel and Joseph
Stulb, both of Philadelphia, Pennsylvania, in the United States of America,)
to be as follows:-
The first part of this Invention consists in certain openings formed in
artificial teeth, and in projections at the side of the latter, so that they can be

page_text: firmly secured to each other and to the vulcanizable gum which forms the
base or support for the teeth. Blocks as well as single teeth heretofore made
to be used with vulcanizable gum bases have been provided with pins and
projections, or have had dovetailed openings in the same, in order that the
vulcanizable gum which surrounds the pins or penetrates the openings may
thus acquire such a hold upon the teeth as will prevent the latter from being
detached. The use of pins for this purpose is objectionable both on account
of the expense of the platina of which the pins are made and the inadequate
surface which they present to the gum. The dovetailed openings are also
objectionable on account of the risk incurred of breaking the teeth in cutting
the openings. Sets of teeth mounted on vulcanizablo gum bases have been
much objected to on account of the exposure of the gum at the point where
two blocks are joined together, this exposure causing the work to present an
unsightly and unnatural appearance in the mouth.
In carrying out this part of the Invention, each block of teeth is formed
with a longitudinal opening extending through the block from one end to the
other, and in the base of the block are two oblong depressions or openings
communicating with the longitudinal opening above named, so that upon the
introduction of the vulcanizable gum through the said depressions or openings
into the longitudinal openings in the blocks (which are placed in juxtaposition),
the gum on hardening will secure the blocks firmly to each other and to the
base. Single teeth may also be formed in a similar manner. It will also be
seen that the projections on the ends of the blocks or teeth may be so fitted
to each other that the gum can pass through the longitudinal opening in one
block or tooth to that in the other without being in the least exposed, the
natural appearance of the teeth being thus maintained.
The second part of the Invention consists in making moulds for forming
artificial teeth substantially as described hereafter, so that depressions and
openings may be formed in the bases of the teeth, and so that the teeth may
be removed from the mould after the depressions and openings have been
made.
In carrying out the second part of the Invention, the moulds are constructed
with fixed projections for forming the depressions or openings in the base of
the blocks, and moveable strips having suitable recesses for forming the
crowns of the teeth, which strips are kept in their relative places by means of
a key. The longitudinal openings are formed, by means of a pin, which is
passed through the mould, in contact with the fixed projections above named.
When the teeth have been moulded and baked, the pins are withdrawn, and
the key is also removed; the moveable strips can then be drawn backward;

page_text: and the teeth can be taken from the mould, when they will be found to have
the longitudinal openings from one end to the other, and also the depressions
or openings in the base communicating therewith as above described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Davies in the Great Seal Patent Office on the
25th November 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County of Middlesex, and
No. 28, St. Enoch Square, in the City of Glasgow, Civil Engineer and Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of May, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said George Davies, Her special license that I, the said George Davies,
my executors, administrators, and assigns, or such others as I, the said
George Davies, my executors, administrators, or assigns, should at any
time agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN ARTIFICIAL TEETH, AND IN MOULDS FOR FORMING THE SAME," (a communication
to me from abroad by John Terrel and Joseph Stulb, both of Philadelphia,
Pennsylvania, in the United States of America,) upon the condition (amongst
others) that I, the said George Davies, my executors or administrators, by an
instrument in writing under my hand and seal, or under the hand and seal
of one of them, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Davies, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement in writing and on reference being had to the accompanying Sheet
of Drawings, that is to say :-
The first part of this Invention consists in certain openings formed in

page_text: artificial teeth, and in projections at the side of the latter, so that they can
be firmly secured to each other and to the vulcanizable gum which forms
the base of support for the teeth.
The second part of the Invention consists in making moulds for forming
artificial teeth substantially as described hereafter, so that depressions and
openings may be formed in the bases of the teeth, and so that the teeth may
be removed from the moulds after the depressions and openings have been
made. Blocks as well as single teeth heretofore made to be used with
vulcanizable gum bases have been provided with pins and projections, or have
had dovetailed openings in the same, in order that the vulcanizable gum
which surrounds the pins or penetrates the openings may thus acquire such a
hold upon the teeth as will prevent the latter from being detached. The use
of pins for this purpose is objectionable both on account of the expense of the
platina of which the pins are made and the inadequate surface which they
present to the gum. The dovetailed openings are also objectionable on
account of the risk incurred of breaking the teeth in cutting the openings.
Sets of teeth mounted on vulcanizable gum bases have been much objected to
on account of the exposure of the gum at the point where two blocks are
joined together, this exposure causing the work to present an unsightly and
unnatural appearance in the mouth.
Such being the nature and object of the said Invention for " Improvements
in Artificial Teeth and in Moulds for forming the same," I will now proceed
to describe more in detail the manner in which the same is to be or may be
performed or carried into practical effect; and in order that the same may be
distinctly understood, I have annexed hereunto a Sheet of Drawings illustrative
thereof, and have marked the same with figures and letters of reference
corresponding with those in the following explanation thereof, that is to
say:
In the accompanying Drawing, Figure 1 represents a block of three teeth
constructed according to these improvements; Figure 2, an inverted plan
view of Figure 1; Figure 3, a section on the line 1-2, (Figure 1); Figure 4,
a vertical section on the line 3-4, (Figure 2); and Figure 5, a perspective
view.
A, A, A, represent three teeth, which together form what is technically
termed a "block," at each end of which is a projection a, for a purpose
described hereafter. Through the block from one end to the other extends
an opening e, and in the base are two oblong depressions i, i, which commu-
nicate with the opening c. It will be seen that blocks of teeth and single
teeth with depressions and openings of the character above represented and

page_text: described may be so placed that the opening e in one block or tooth shall
coincide with that in the block or tooth next to it, so that the introduction of
the vulcanizable gum which forms the base through the depression i, into the
opening e, will, when the gum hardens, secure the blocks firmly to each
other and to the base. It will also be seen that the projections a on the
ends of the blocks may be so fitted to each other that the gum can pass
through the opening e in one block to that in the other without being in the
least exposed, the natural appearance of the teeth being thus maintained.
The second part of the Invention, which relates to moulds for forming
artificial teeth, is illustrated in Figures 6, 7, 8, 9, and 10; Figure 6 being a
plan view, with the top removed of the improved mould for forming artificial
teeth; Figure 7, a transverse section on the line 1-2, (Figure 6); Figure 8,
a longitudinal section on the line 3-4, (Figure 6); Figures 9 and 10, sectional
views drawn to an enlarged scale of the teeth made by the moulds. A is the
bottom plate of the mould, the centre of which throughout its length between
the lines x, x, and x, x¹, (Figure 6), is a plain surface. That portion of the
mould between the lines a, and each side of the same is raised above the
level of the central part in the form of a succession of arched projections
b, b', 6, (Figure 8), the central portion of each projection being cut away in
order to admit a block C, on the inner face of which are one or more
projections a, these blocks C being permanently secured in their places by
pins e, (Figure 7). D and D' are strips of metal, in which are cut at points
opposite the blocks C, depressions i, i, corresponding to the form which it is
desired to give to the blocks and crowns of the teeth, the said strips being
separated from each other by a key E, which serves to keep them pressed
tightly against the inner sides of the raised portion of the mould. The cap of
the mould (shown in dotted lines, Figure 7,) resembles those generally used
in moulds for casting teeth; G.and G¹ are pins which can be introduced into
the moulds through suitable openings in the ends of the same, the said pins
when in the moulds occupying such a position that they project across the
faces of the blocks C, and just touch the ends of the projections a, any portion
of the mould which would interfere with the introduction of the pin being cut
away. When teeth are to be formed in the moulds, the pins G are secured
in the position shown in Figure 6, and the plastic material of which the teeth
are to be made is introduced, care being taken that the material penetrates
all the interstices below and around the projections a. The cap of the mould
is then secured in its place, and the mould heated until the material therein
is sufficiently baked. The pins G are then withdrawn, the cap is detached,
and the key E removed, which permits one of the strips D to be moved back

page_text: until it strikes the side of the other. The baked material (now in the form
of blocks of teeth) may be then removed by sliding each block forward, so as
to release the rear of the same from the projections a, and then lifting it from
the mould. When all the blocks on one side have been removed, the other
strip D may be moved back, and the operation repeated on the other side.
It will be found that the blocks of teeth cast in this manner have oblong or
other shaped depressions in their bases, corresponding to the shape of the
projections a, and that these depressions communicate with an opening (made
by the pins G) which passes longitudinally through the block. This will be
best understood by referring to the enlarged views of the teeth in Figures 9
and 10, Figure 9 being a transverse section of the block of teeth, and Figure 10
a longitudinal section on the line 5-6, (Figure 9), the dotted lines showing
the direction taken by the pins G through the block of teeth, the depressions
in which are made between the points m, m, and n, n, by the projections a.
It will be apparent that the moulds may be constructed so as to make
depressions of any shape and size in the bases of blocks of teeth for securing
the same to vulcanizable gum bases and to each other. It should be under-
stood that when the mould is in a finished state the blocks C are permanently
secured in their places, the only object in making them separate from the
mould in the first instance being that the projections a may be more readily
formed. Depressions have been heretofore made in the bases of teeth by
forming projections in the mould, but these projections have been formed on
blocks arranged to slide outwards, so that the teeth might be removed, whereas
in the mould above described the projections for forming the depressions in
the teeth are stationary, the removal of the teeth being effected after the
withdrawal of the key E, and the moving of the strips D and D' in the manner
described above.
י
Having now particularly described the nature and object of the said Invention
for "Improvements in Artificial Teeth and in Moulds for forming the same,"
together with the manner in which the same is to be or may be performed or
carried into practical effect, I would remark in conclusion, that I claim (as the
Invention communicated to me by John Terrel and Joseph Stulb),-
Firstly, the depressions i, i, and opening e, formed within a tooth or block
of teeth, so that the latter may be secured to the vulcanizable gum bases as
described.
Secondly, the projections a, arranged at the sides of the teeth to prevent the
exposure of the vulcanizable gum at the joints between the teeth as set forth.
Thirdly, so constructing the moulds, that by means of the stationary
projections a, the moveable strips D, and key E, depressions may be made

page_text: in the bases of the teeth, and the latter be removed from the mould as
specified.
Fourthly, the use of moveable pins G for forming openings in the teeth as
described.
In witness whereof, I, the said George Davies, have hereunto set my
hand and seal, this Twenty-fifth day of November, in the year of our
Lord One thousand eight hundred and sixty-four.
GEORGE DAVIES. (L.S.)