IMPROVEMENTS IN ARTIFICIAL DENTURES AND IN BASES FOR THE SAME.
Year: 1871

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's. Inn
,,
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN ARTIFICIAL DENTURES AND IN BASES FOR THE SAME.'
A communication from abroad by Thomas Alder Dickson Forster,
of Philadelphia, Pennsylvania, United States of America.
Sealed the 23rd April 1872, and dated the 23rd November 1871.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 23rd November 1871.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN ARTIFICIAL DENTURES AND IN BASES FOR THE
SAME," a communication to me from abroad by Thomas Alder Dickson
Forster, of Philadelphia, Pennsylvania, United States of America, to be
as follows:

page_text: hereafter, with the view to the attainment of economy both as regards
the cost of the materials used and the process of converting the same
into artificial dentures.
Also in making bases of artificial teeth either in whole or in part of
oxychloride of zinc, which during the process of manufacture can be
manipulated while cold, and therefore more easily and rapidly treated
than the compositions which have to be manipulated while hot.
The object of the first part of this Invention is to economise the
manufacture of artificial dentures having composition bases or bases
partly of composition and partly of metal, by dispensing entirely with the
costly porcelain teeth and blocks of teeth having tinted extensions,
which form imitations of the gums heretofore employed.
The said Invention has also for its object a more perfect representation
of the exposed portion of the gums. This is accomplished by using
single plain teeth, and by tinting that portion of the composition base
which represents the exposed gums.
When carrying this Invention into effect, in connection with hard
rubber, it is proposed to embed in the usual manner in the base of that
composition the fangs of cheap single teeth while the material is in a
plastic state, the rubber being subsequently hardened. Instead of relying
upon the usual tinted extensions of the teeth to form and imitate the
exposed portions of the gums, the latter are formed in the mould on and
as a part of the base itself, but as the base is not of appropriate tint a
varnish or enamel is used, consisting generally of gun cotton dissolved in
ether or its equivalent mixed with carmine or other appropriate color to
impart the desired tint. This enamel is spread over the exposed portion
of the base, becomes thoroughly incorporated with the same, and inde-
pendently of the color imparted presents a highly polished surface,
bearing a more close resemblance to the natural gum, owing to its
uniform continuity and exactitude of shape as derived from the mould,
than any tinted extension of ordinary porcelain teeth, which demand
such tedious manipulation before they can be jointed to approximately
represent a continuous gum surface.
The color of a collodion or celluloid base bears a closer resemblance to
the color of the gums than an ordinary rubber base, so close a resemblance
in fact that in some cases a transparent colorless enamel of gun cotton
and ether may be used to impart the desired polish and brilliancy, or the

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 21st May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of November, in the
year of our Lord One thousand eight hundred and seventy-one, in
the thirty-fifth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Henry Johnson,
Her special license that I, the said John Henry Johnson, my
executors, administrators, and assigns, or such others as I, the said
John Henry Johnson, my executors, administrators, or assigns, should
at any time agree with, and no others, from time to time and at
all times thereafter 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 DENTURES
AND IN BASES FOR THE SAME," a communication to me from abroad by
Thomas Alder Dickson Forster, of Philadelphia, Pennsylvania, United
States of America, upon the condition (amongst others) that I, the
said John Henry Johnson, my executors or administrators, by an
instrument in writing under my hand and scal, should particularly

page_text: 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 John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, that is to say :-
The said Invention consists in manufacturing artificial dentures having
bases wholly or partly of composition, in the peculiar manner described
hereafter, with the view to the attainment of economy both as regards
the cost of the materials used and the process of conventing the same
into artificial dentures.
Also in making bases of artificial teeth either in whole or in part of
oxychloride of zinc, which during the process of manufacture can be
manipulated while cold, and therefore more easily and rapidly treated
than the compositions which have to be manipulated while hot.
In making artificial dentures with bases of hard rubber, celluloid,.or
other composition, it has been the invariable practice to embed porcelain
teeth, extended and tinted so as to assume both the shape and color of
the exposed portion of the gums into the material while it is in a plastic
state, and to subsequently harden the material. United groups or
blocks of teeth thus extended and tinted so as to represent both teeth
and gums are generally employed in the formation of artificial dentures,
and much tedious manipulation is demanded in jointing the blocks
together so as to represent a continuous surface similar to that of the
natural gum.
Porcelain teeth extended and tinted to imitate the color of the gums,
and especially blocks of such teeth, are moreover double or nearly
O double the expense of plain teeth which can be much more easily
fitted together.
The object of the first part of this Invention is to economize the
manufacture of artificial dentures having composition bases, or bases
partly of composition and partly of metal, by dispensing entirely with
5 the costly porcelain teeth and blocks of teeth, having tinted extensions
which form imitations of the gums heretofore employed.

page_text: The said Invention has also for its object a more perfect represen-
tation of the exposed portion of the gums. This is accomplished by
using single plain teeth, and by tinting that portion of the composition
base which represents the exposed gums.
When carrying this Invention into effect in connection with hard
rubber it is proposed to embed in the usual manner in the base of that
composition the fangs of cheap single teeth, while the material is in a
plastic state, the rubber being subsequently hardened. Instead of
relying upon the usual tinted extensions of the teeth to form and
imitate the exposed portions of the gums, the latter are formed in the
mould on and as a part of the base itself, but as the base is not of appro-
priate tint it is proposed to use a varnish or enamel consisting generally
of gun cotton dissolved in ether or its equivalent, mixed with carmine
or other appropriate color to impart the desired tint. This enamel is
spread over the exposed portion of the base, becomes thoroughly incor-
porated with the same, and independently of the color imparted presents
a highly polished surface bearing a more close resemblance to the natural
gum, owing to its uniform continuity and exactitude of shape as derived
from the mould, than any tinted extensions of ordinary porcelain teeth,
which demand such tedious manipulation before they can be jointed to
approximately represent a continuous gum surface.
The color of a collodion or celluloid base bears a closer resemblance
to the color of the gums than an ordinary rubber base, so close a
resemblance in fact that in some cases a transparent colorless enamel of
gun cotton and ether may be used to impart the desired polish and
brilliancy, or the varnish may be slightly colored to graduate the tint
already existing in the base.
The second part of my Invention relates to a composition for the bases
of artificial dentures. This improved composition for bases consists of
oxychloride of zinc, made by mixing together oxyide and chloride of zinc
in such proportions as to form a plastic mass, and so coloring the same
that the composition will represent as nearly as possible the natural color
of the gum.
The teeth are mounted on wax or gutta percha in the usual manner,
and are imbedded in the plaster of a sectional mould, and after the
removal of the wax the plastic material is introduced in its place and
retained within the mould until the material is hardened, the whole

page_text: process being conducted without the application of heat. Finely
powdered ground silex, or other equivalent material, may be added to
the oxychloride so as to give body and additional strength to the same.
In connection with the improved oxychloride base it is preferred to
use single plain teeth, and to form the imitation of the exposed portion
of the gum on the base by tinting, if necessary, and enamelling the same,
as herein-before described in reference to the first part of this Invention.
The oxychloride may form a portion only of the base, it may for instance
be backed with metal, or the greater portion of the base may consist of
metal, to which the teeth are united by oxychloride, which forms the
imitation of the exposed portion of the gums.
Prior to the application of the enamel to the oxychloride base the
inventor coats the latter with a solution of gum sandarac or other
equivalent resinous gum, which acts as a medium for causing the
adhesion of the enamel.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to
be novel and original and therefore claim as the Invention secured to me
by the herein-before in part recited Letters Patent is,―
First. An artificial denture having a base wholly or partly of compo-
sition, and the imitation of the natural gum formed of and composing a
a part of the said composition, as herein-before set forth for the purpose
specified.
Second. An artificial denture in which plain single teeth are imbedded
in a composition base of which a portion is made in imitation of the
exposed portion of the natural gums.
Third. An artificial denture the base of which is composed wholly or
in part of oxychloride, with or without other ingredients.
Fourth. The use of the said oxychloride base tinted to represent the
natural color of the gums.
Fifth. The coating of composition bases or parts of the same with an
enamel consisting of gun cotton and ether or equivalent solvent, which
will act as a partial solvent of the base to which it is applied.

page_text: Sixth. The employment of the said enamel tinted to imitate the
natural color of the gums.
Seventh. The application of gum sandarac, on its equivalent, to oxy-
chloride bases prior to the application of the said varnish or enamel to
the same, for the purpose specified.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Eighteenth day of
May One thousand eight hundred and seventy-two.
J. HENRY JOHNSON. (L.S.)