AN IMPROVED PLATE OR BASE FOR ARTIFICIAL TEETH
Year: 1871

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London, for
the Invention of "AN IMPROVED PLATE OR BASE FOR ARTIFICIAL TEETH."
-A communication from abroad by Isaiah Smith Hyatt, John
Wesley Hyatt, junior, and Jesse A. Perkins, M.D.S., all of Albany,
Now Vaub United States of
COMPLETE SPECIFICATION filed by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 18th April 1871, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVED
PLATE OR BASE FOR ARTIFICIAL TESTH," and have petitioned Her Majesty to
grant unto me, my executors, administrators, and assigns, Her Royal

page_text: Letters Patent for the same, and have made solemn Declaration that
it has been communicated to me from abroad by Isaiah Smith Hyatt,
John Wesley Hyatt, junior, and Jesse A. Perkins, M.D.S., all of Albany,
New York, United States of America.
•NOW KNOW YE, that I, the said William Robert Lake, do hereby t
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention,
and in what manner the same is to be performed, in and by the
following statement :-
1
In the manufacture of dental plates or bases for artificial teeth, 1
vulcanite or hard rubber which has been extensively employed for the
purpose has been found objectionable on account of its dark colour,
offensive taste and smell, liability to break when chilled, and difficulty
of repairing the plates when broken; moreover there is a large amount
of mercury contained in the colouring material (vermillion) employed
which renders it particularly obnoxious to some persons, while in addition
to the length of time required to manufacture the plates its qualities
render it unpleasant for dentists to manipulate. To obviate these
objections various experiments and attempts have been made to sub-
stitute for such plates compounds of pyroxiline or solid collodion
which have hitherto failed to accomplish the desired result. In these
experiments collodion has been employed in a partially dissolved state
in which it is placed in the casts or moulds containing the teeth and
subjected to pressure, and from plates thus formed the solvent material
gradually evaporates. This evaporation is attended with such an amount
of shrinkage as to warp the plates and impair their shape, and this
difficulty in connection with the tedious nature of the process has pre-
vented the adoption of this and similar methods of using pyroxiline.
An attempt has also been made to avoid this shrinkage of the formed
plates by subjecting the collodion in a nearly dried state to pressure in
heated moulds, and then attaching the teeth thereto by the use of
powdered collodion and a solvent. This method has also failed for tho
reason, among others, that the drying of the material by which the teeth
are soldered in place has, a tendency to leave the teeth loose, while tho
connection is rendered, still lèss secure on account of the more porous a
nature of this soldering material which is not subjected to pressure as
is the main body of the plates, the line of junction also being frequently
discernible from a difference in appearance.

page_text: This Invention relates to a dental plate or base for artificial teeth
composed of a kind of solid collodion, in which the transformation of the
pyroxiline is effected by the use of camphor as a solvent, whereby the
thoroughly dried product or collodion is rendered plastic by heat so as
to be readily moulded without subsequent shrinkage as hereafter described,
and without the use of fixed oils or fusible non-solvent gums which are
required to be combined with the material when ether, alcohol, or other
solvents are used; these fixed oils and gums forming a part of the
permanent compound impair its strength, durability, purity, firmness
of texture, and other qualities essential in a dental platė.
'
In the manufacture of collodion for these improved dental plates I
prefer to use at least fifty parts by weight of gum camphor to one.
hundred parts of soluble cotton (a greater proportion of camphor may be
used) whereby the product is rendered more plastic than when a less
quantity is employed. The collodion thus produced is made into plates
of suitable thickness which are preferably formed into shapes approxi-
mating to those of finished dental plates by pressure in heated moulds.
The plates thus formed are now thoroughly dried by placing them in a
drying room heated to a temperature which should not exceed 180°
Fahrenheit, 150° to 180° being the temperature found best adapted for
expelling the camphor solvent. A temperature much higher than 200°
will expand the material and render it porous and brittle. The plates
when properly dried, although freed from liability of shrinkage still
retain the quality which enables them to become plastic under a proper
degree of heat, and may be readily moulded into any desired shape
without subsequently shrinking to any injurious extent. In making a
set of teeth with this improved base, the case is prepared and teeth set in
plaster by the same process and in the same manner as is done in making
a set of hard rubber, except that the trial plate should be made thinner.
Care should be taken to use the best quality of plaster and to thoroughly
dry the casts before proceeding with the final process. Around the
outside of the teeth next to the flask is cut a channel connected by.
short channels or gates with the inside to receive the excess of
material. When the flasks are thus prepared a plate or base is placed
; in the lower flask and the upper flask upon it, when the two flasks are
put into a screw, clamp ready to be forced together. The flasks and
clamp are then set into a small tank of oil (good sweet oil works well
and emits no odour) and a gas jet or alcohol lamp placed under the the oil

page_text: tank is lighted and the oil heated to 300° (never above 310° Fahrenheit)
on a thermometer attached to the vessel. As the oil heats the plate
becomes softened and plastic, when the clamp is gradually screwed down
to place, scarcely any force being required until the last, when the proper
degree of heat being reached the flasks are forced firmly and completely i
together. The clamp and flasks are then lifted out of the oil, and if
the flasks are seen to be entirely together on all sides the work of
moulding is done. The flasks and contents are then immersed in cold
water and thoroughly cooled, when upon opening the flasks the case
will be seen to be moulded in the most perfect manner, the teeth firmly 1
attached, and the shape of the plaster moulds perfectly taken to the
minutest particular. The case is then freed from plaster with a brush
and water, finished, and polished as would be done with rubber. Chalk
is used as a last finish with cotton, wheel, and water. Among the
advantages of this new base are the following:-
First. It is lighter and at the same time stronger than dental vulcanite
or hard rubber.
Second. Its colour is very near that of the natural gum, and will not
change in the mouth."
Third. It is entirely free from all unpleasant taste.
"
Fourth. It is not injurious to any mouth, even the most sensitive,
which is not the case with rubber plates containing a large amount of
mercury, and it is more pleasant and comfortable to the wearer than
plates made of any other known material.
1
Fifth. It can be manufactured and fitted to the mouth more easily,
quickly, and satisfactorily to the operator than any other known base
for artificial teeth, saving time and trouble enough to the operator to
pay for the plate, and requiring only from one-third to one-quarter of
the time used in working rubber. Everything is neat, convenient, and
clean, and no unpleasant odour fills the room or attaches to the hands
of the dentist.
Sixth. After being thoroughly dried it is easily rendered plastic by
heat so as to be readily moulded, while it is free from all liability of
shrinking, and consequent warping and derangement of shape after it
has been furnished with a set of teeth, which is one of its most important
advantages.

page_text: Having thus fully described the said Invention as communicated to
me by my foreign correspondents and shown how the same may be con-
veniently and advantageously carried into practice, I claim the dental
plate or base for artificial teeth substantially as herein described.
In witness whereof, I, the said William Robert Lake, havo here-
unto set my hand and seal, this Eighteenth day of April, in the
year of our Lord One thousand eight hundred and seventy-one.
Witness,
E. O. JACKSON.
WILLIAM ROBERT LAKE. (L.S.)