IMPROVE- MENTS IN THE MANUFACTURE OF MODELS AND OF PLATES OR PIECES FOR ARTIFICIAL TEETH, AND IN COMBINING OR AMALGAMATING INDIA-RUBBER AND GUTTA PERCHA WITH METALS FOR THE MANUFACTURE OF ARTIFICIAL PLATES OR PIECES, AND FOR OTHER PURPOSES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Matthew Cartwright at the Office of
the Commissioners of Patents, with his Petition, on the 16th April
1862.
I, MATTHEW CARTWRIGHT, of St. John's Row, Hoxton, in the County of Middle-
sex, Dentist, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF MODELS AND OF PLATES OR PIECES FOR ARTIFICIAL
TEETH, AND IN COMBINING OR AMALGAMATING INDIA-RUBBER AND GUTTA PERCHA
WITH METALS FOR THE MANUFACTURE OF ARTIFICIAL PLATES OR PIECES, AND FOR
OTHER PURPOSES," to be as follows:-
My Invention consists, first, in making models used in preparing plates or
pieces for artificial teeth of vulcanite, ebonite, or hardened rubber, alone or
combined with soft vulcanized rubber, in the manner hereafter described. I
take a cast or impression of the mouth in wax, coat the surface of it with
plaster of Paris, and when dry paint it with a mixture composed of oil and
vermilion. The cast or impression then receives a second coat of plaster,
which when dry again receives a coat of oil and vermilion, and so on until it
is sufficiently thick for the purpose to which it is to be applied. The wax is
removed, and the whole is coated with vermilion and oil, as before. The
model just made is inserted in the lower half of a flask containing liquid
plaster, from which, when hardened, the model is removed, and its counterpart
or impression is reproduced in the plaster. The space formed by the model in
the plaster is now filled with wax, and the rest of the plaster coated with

page_text: vermilion and oil. The upper half or portion of the flask is now placed on the
lower half and filled with liquid plaster, a cover is placed on it, and the whole
allowed to harden. The upper and lower flasks are now divided, the wax in
the lower flask is picked out, and the space thereby formed is filled up with
the composition of india-rubber to form vulcanite. The flasks are again put
together, heated, and subjected to pressure in the ordinary manner; and the
rubber is finally vulcanized. This done the flasks are opened and the model
removed. To produce a counter-model in vulcanite I coat the vulcanite
model with black lead, lampblack, bronze, goldbeater's skin, or other suitable
material, and place it in the lower half of the flask (that part representing the
mouth being, uppermost) which contains soft plaster where it is allowed to
harden. The whole, or as much of the model as necessary, is now covered
with wax, and the lower half painted in the ordinary manner. The upper half
of the flask, which is filled with plaster, is now put on, the lid is also placed
on and the whole allowed to harden. This accomplished the flasks are sepa-
rated, the wax removed, and india-rubber composition inserted in the cavity it
occupied. The flasks are again put together, heated, pressed, and the india-
rubber vulcanized in the ordinary manner.
Sometimes I form the models and their counterparts by painting the india-
rubber when in a liquid state on the model, each coat being dry before the
next is applied.
When an elastic model is required, soft and hard rubber are used alter-
nately; or hard rubber in combination with cotton, or any other material
capable of rendering it elastic. For rendering plates or pieces suitable for
palates, gums, or bands elastic I coat the base with, for example, two coats of
hard rubber, then I apply a series of coats of soft rubber, and so on according
to the degree of thickness and elasticity required, and this may be done in
combination or not with any other material capable of rendering it-clastic,
such as cotton, cotton fabric, asbestos. Where strength is required hard
rubber must exceed the soft, and where elasticity is required the soft rubber
must exceed the hard. Plates or pieces made in the manner before described
may be coated with crystal, or plastic gold, gold leaf, platina leaf, tinfoil,
gold shell, silica, filings of gold, or other metal, in the following manner :-I
adapt crystal or plastic gold to the models by consolidating it on them, the
surface of the gold being roughened; the gold then receives a coating of liquid
composition to form vulcanite; the model is then placed in a "digester," or
oven to heat it. When removed it is again coated with a composition, as
before, and so on until the desired thickness is obtained. When perfectly
solid another layer, or even two or more layers of hard india-rubber is or are

page_text: added, and crystal gold adapted to it. The whole is vulcanized.. I adapt gold
leaf, tin or platina foil to the models by means of a sponge or other soft
material (when thick foil is used it must be rendered porous); the foil then
receives a coating of hard india-rubber, and is heated. The upper part of the
piece is coated with gold filings, precipitated gold, or gold shell by scattering
the filings upon the surface previous to its being dry, and applying the gold
shell when the surface is partially dry. To cover that part fitting the mouth
with gold shell I paint the model with it by means of a camel-hair brush. In
all cases I prefer the metal leaf to be roughened. To apply silica to the
plates I take an impalpable powder of it and paint it on by dipping the brush
in a solution of sugar and water. The silica may be colored when desired.
My Invention in so far as it regards the combination of india-rubber and
gutta percha with metals for the manufacture of artificial plates or pieces, and
for other purposes, consists in reducing the rubber or gutta percha to a liquid
state, and mixing (say) gold therewith. The rubber or gutta percha thus
treated is thereby colored, and to all appearance resembles a piece of pure
gold. This part of my Invention is applicable to ornamenting india-rubber
and gutta percha articles generally, the quantity of metal being regulated
according to the color or design to be produced.