Improved Means for Attaching Artificial Teeth to Metal Frames.
Year: 1890

page_text: Da of Application, 19th Feb., 1890
=
Complete Specification Left, 22nd Nov., 1890-Accepted, 10th Jan.. 1891
PROVISIONAL SPECIFICATION.
Improved Means for Attaching Artificial Teeth to Metal Frames.
I CHARLES SAMUEL LEADBETTER of 71 New Bridge Street Manchester in the
County of Lancaster Registered Dentist, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improved means for attaching artificial teeth by vulcanizing
to frames made of a metal or alloy inferior to gold or platinum.
Hitherto artificial teeth have only been vulcanized onto frames made of pure gold,
and certain other valuable metals and alloys, as inferior metals or alloys could not be
used with advantage for this purpose, either because the vulcanite would not properly
adhere thereto or on account of the vulcanization blackening or otherwise deteriorating
the surface of the inferior metal or alloy, or that the inferior metal or alloy would not
resist the action of the acids of the mouth, or else that it became corroded or otherwise
unpleasant or unsafe to the wearer in use.
Attempts have been made also to electroplate with gold the inferior metal after the
teeth has been applied thereto, but this has proved equally unsuccessful mainly on
account of the difficulty of vulcanizing onto the electro-gold and also that not only is
the cyanide used in the electro-gilding process poisonous in itself but it was found
that in use deleterious chemical combinations took place which caused corrosion of the
metal, and were otherwise dangerous and unpleasant to the wearer.
According to my invention I apply the coating of gold or other precious metal or
alloy to the inferior metal or alloy by means of a flux (such for instance as borax) in
combination with heat somewhat as is practised in tinning sheet iron or other metals
or by fusion or any other analogous calorific process where the junction of the metals
is effected by hea'.
The gold or other precious metal or alloy may be applied to plates of the inferior
metal or alloy in the form of leaf and affixed by the calorific process or the
combination may be made in the ingot and the combined metals rolled out into sheets
of the required thickness.
Having by either of these means formed the plates of combined metal into the
shape of the required frame I then attach the artificial teeth thereto by means of
vulcanite in the same manner as is practised with the frames of pure gold or other
precious metal or superior alloy, and it will be found that by combining the gold with
the inferior metal or alloy by the fusion or other analogous calorific process there is
no difficulty in vulcanizing the artificial teeth thereto, and that no corrosion or other
deleterious chemical action takes place, and in use such plates are to all intents and
purposes as pure and unobjectionable as plates or frames of pure gold, platinum, or
superior dental alloy, and are considerably less expensive; whereas the teeth could
not be vulcanized direct onto the inferior metal or alloy without the intervention of
the gold or other precious metal or superior dental alloy, and as before stated this
must be applied to the inferior metal or alloy by fusion or other analogous calorific
process.
In some cases also I propose to perforate punch or otherwise roughen the surface
of the plate, before applying the vulcanite so as to facilitate the adhesion of the
vulcanite thereto.
11: 10.1 1
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improved Means for Attaching Artificial Teeth to Metal Frames.
I CHARLES SAMUEL LEADBETTER formerly of 71 New Bridge Street, now at 61
Great Ducie Street, Strangeways, Manchester, in the County of Lancaster, Registered
Dentist, do hereby declare the nature of uny said invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement:-
This invention relates to improved means for attaching artificial teeth by vulcanizing
to frames made of a metal or alloy inferior to gold or platinum.
Hitherto artificial teeth have only been vulcanized onto frames made of pure gold
and certain other valuable metals and alloys, as inferior metals or alloys could not be
used with advantage for this purpose because the vulcanite would not properly adhere
thereto on account of the vulcanization blackening or otherwise deteriorating the
surface of the inferior metal or alloy, or that the inferior metal or alloy would not
resist the action of the acids of the mouth, or else that it became corroded or otherwise
unpleasant or unsafe to the wearer in use.
Attempts have been made also to electroplate with gold the inferior metal after the
teeth have been applied thereto, but this has proved equally unsuccessful mainly on
account of the difficulty of vulcanizing onto the electro-gold and also that not only
is the cyanide used in the electro-gilding process, poisonous in itself but it was found
that in use deleterious chemical combinations took place which caused corrosion of the
metal and were otherwise dangerous and unpleasant to the wearer.
According to my invention I apply the coating of gold or other precious metal or
alloy to the inferior metal or alloy by means of a flux (such for instance as borax) in
combination with heat, somewhat as it is practised in tinning sheet iron or other
metals or by fusion or any other analogous calorific process where the junction of the
metals is effected by heat.
The gold or other precious metal or alloy may be applied to plates of the inferior
metal or alloy in the form of leaf and affixed by the calorific process or the
combination may be made in the ingot and the combined metals rolled out into sheets
of the required thickness.
Having by either of these means formed the plates of combined metal into the
shape of the required frame I then attach the artificial teeth thereto by means of
vulcanite in the same manner as is practised with the frames of pure gold or other
precious metal or superior alloy and it will be found that by combining the gold with
the inferior metal or alloy by the fusion or other analogous calorific process, there is
no difficulty in vulcanizing the artificial teeth thereto and that no corrosion or other
deleterious chemical action takes placo, and in use such plates are to all intents and
purposes as pure and unobjectionable as plates or frames of pure gold, platinum or
superior dental alloy and are considerably less expensive, whereas the teeth could
not be vulcanized direct onto the inferior metal or alloy without the intervention of
the gold or other precious metal or superior dental alloy and as before stated this
must be applied to the inferior metal or alloy by fusion or other analogous calorific
process.
In some cases also 1 propose to perforate, punch or otherwise roughen the surface
of the plate before applying the vulcanite so as to facilitate the adhesion of the
vulcanite thereto.
To effect the purposes of my invention I produce first a mechanical calorific union
on one or both sides between a superior and an inferior metal or metal alloy of about
or of a lower quality of fineness than 16 carat gold. In order to do this I make an
ingot of inferior metal calculated-ascertained by comparative weight or by metal
gauge when made and in proper shape, levelled down on the surface or surfaces to
he operated upon as will when done provide on one side only or on both sides if
desired to shew a thickness of the superior metal of about one eighteenth of that of
the thickness of the inferior metal when rolled down in the aggregate to the strength

page_text: comparatively of an ordinary No. 5 metal gauge denial metal plate or a thicker
proportion of the superior metal if required.
To make this calorific union of the inferior and superior metals more certain I use
a series of special fluxes as hereinafter described, graduated to accord somewhat with
the recognised known properties of the superior and inferior metals and metal alloys
brought in this way into unicn as follows:-
No. flux, the concentrated essence of borax. I dissolve one ounce of borax
with ten ounces of clear water and heat to boiling temperature, then cool and when cold
filter through a cotton wool filter and then concentrate the solution by evaporation
down to one ounce and to this concentrated solution I add one tenth of an ounce of
No. 2 flux.
No. 2 flux-the concentrated essence of zinc and salamoniac. I dissolve in two
ounces of hydrochloric acid as much pure sheet zinc as it will contain by exhibiting
surplus undesolved zinc.
Dissolve one ounce of salamoniac in ten ounces of water and heat to boiling point
then cool and when cold filter through a cotton wool filter, & filter also the zine
solution in the same way, then by evaporation concentrate the zine solution a third
less and the salamoniac to one ounce and then mix the two together
No. 3 flux-the concentrated essence of borax, the concentrated essence of zinc
solution and the concentrated essence of salamoniac. I mix with one ounce of the
former (borax), two tenths of an ounce of the latter.
No. 4 flux, consists of the aforesaid concentrated essence of zinc solution alone or
with one tenth of the essence of salamoniac added.
When the aforesaid inferior gold ingot or ingots are made as aforesaid I then cut
similar sized (one or more) pieces of superior gold plate by preference of 23 carat
fineness of a thickness agreeable to the aforesaid computation by rolling through a
pair of tempered steel rollers to the desired gauge or thickness and when this has
been done I roughen the surface on one side only or on both sides if necessary of the
inferior ingot or ingots with a bastard cut hand file or other rough cut file and at
once cover the perfectly clean roughened gold surface or surfaces with No. 1 flux
aforesaid, when this has been done clean the surface to be used of the thinner superior
ingot of gold, then with one or two of these if desired cover the fluxing side or sides
of the aforesaid inferior gold ingot, then bind together with fine soft steel binding
wire, then place it on a sheet of thin steel in a simple muffle in an ordinary stove or
in an ordinary grated fire stand or in an ordinary fire grate, heated with a suitable
fuel such as the coke used by brass founders, assisted with a suitable blower to create
a good draft until heated to a white heat closely watching until the superior gold plate
is seen to sink a little, then withdraw it to the mouth of the muffle for a moment then
finally withdraw it as this incident indicates that the union of the plates has become
perfect. Or when at a good red heat in the muffle I withdraw it and complete the
operation with the ordinary or special mouth blow pipe and when cool I loosen the
binding wires and boil in a pickle of one part of sulphuric acid and thirty parts of
water I then roll down-annealing occasionally in a muffle as aforesaid on strong sheet
iron gauze with a pair of steel rollers until No. 5 gange or other ordinary size of
dental plate thinness has been arrived at.
To coat a silver ingot with a gold ingot I proceed as aforesaid but with No. 3 flux,
the quality of silver prepared is 19 dwts. 6 grains of fine silver to 18 or less grains of
fine copper to the ounce; the union between the silver and gold ingot being hastened
by the addition of another one tenth of the No. 1 flux.
With the superior nichol alloy, or nichol ingot, I proceed, as aforesaid using for a
flux the clear filtered concentrated zinc solution and one tenth of salamoniac alone.
With imitations of silver and imitations of gold I proceed as aforesaid, keeping in
mind the fact that alloys of this description melt at a lower. temperature than the
superior metals using a combined flux composed of equal parts by weight of the con-
centrated zinc solution and salamoniac then thinning out as aforesaid.
With imitations of platinum and similar metals I proceed as aforesaid using No. 3
flux, then thinning out as aforesaid.

page_text: Any of these inferior ingots may be united to the superior ingots by soldering them
together with easy flowing solders of the several appropriate degrees of fine metal
entering into their compounding providing for the superior ingot being of a slightly
less size to lodge the solder round and on the inferior ingot to enable it when at the
proper heat to flow or flush the two into one and when two gold coated sides are
required, repeating the process on that side which remains uncoated, then thinning
out as aforesaid.
With pure platinum made very soft by annealing I proceed as aforesaid but before
fixing the gold coating ingot to the platinum ingot I sweat on to the platinum with
the blow pipe or through the muffle a leaf of 23 carat gold, using for a flux No. 1, made
thin by adding double the quantity of water to it, then I proceed as aforesaid to unite
the one or the two gold ingots to the platinum. The platinum ingot is by preference
thin and the gold coat on one side only thicker than the average. Or I reduce fine
gold (goldbeaters) leaf to a powder by mixing as much of it as possibly can be got into a
small or given quantity of the concentrated zinc and salamoniac flux No. 3 in a
mortar or similar vessel well pounding it and when this has been done to a thick
pasty condition or by evaporation reduced to that consistency with a small or suitable
camel hair brush I spread it over one side of any of the aforesaid ingots of inferior
metal or a pure platinum ingot and sweat in and on to the ingot through the muffle
or by any similar known aids to this end when this has been done 1 boil out in the
aforesaid pickle and repeat the process on the other side if required repeating the
process on one side and then on the other side if desired until the desired thickness
of the gold coating has been brought about. I then roll the ingot out to the desired
thinness, or treat an ordinary gauged No. 5 dental metal piece of plate in a similar
manner on one or both sides, one or more times and if skillfully done will stand a
coating of vulcanite through the vulcaniser. Or reduce chloride of gold by
evaporation to a paste then spread as aforesai and gold-coat as aforesaid by gold
powder. Or in a suitable vessel I make a bath solution by weight of distilled water
100 parts, hyposulphite of soda 9 parts, pure glycerine 40 parts and after mixing add
1 part of chloride of gold with 3 parts of distilled water and warm the aforesaid
solution indirectly with boiling water or with dry heat to boiling water temperature,
then thoroughly cleanse an ingot of inferior metal in the aforesaid pickle, after
boiling it cleansing it in fresh clean water and binding it with a narrow strip of clean
sheet zine and dip it into the aforesaid gold solution made hot as aforesaid and keep
it for a short time therein when it will be gold coated. The solution may be made
to bite keener and leave on a thicker coat of gold by adding one or more parts by
weight of caustic soda or one part of cyanide potassium neutralised by the calorific
process, I then pass the ingot through the calorific process as aforesaid and repeat
the operation until the desired thickness has been brought about or I use this method
as a foundation for building up the other aforesaid thick coatings of superior
gold ingot and reduce the ingot after being treated as aforesaid to the desired
thinness.
To gold coat an ingot or a No. 5 gauge aluminium alloy plate, or to put it
another way to coat a thin ingot of 23 carat gold with a thick aluminium alloy ingot
which will when done roll out through a pair of steel rollers to a sheet of metal
of the thinness in the agregate which will shew a thinness of one of gold to 18 of
aluminium, I proceed as follows. If for one side only or for both sides of the
aluminium metal I make a sheet iron or other thin ladel well scoured and cleaned on
the inside, and in this I melt a given quantity of dental aluminium metal and when in
the molten state mix in by degrees a similar quantity of pure Russian tin leaf, stirring
up well on the introduction of every piece of tin, when the tin and aluminium have
become thoroughly amalgamated run the whole off on to a red hot iron plate or
similar smooth surfaced metal plate and at the same moment cover it with a similar
hot metal plate and subject it to considerable pressure to leave the molten metal about
the thickness desired, leave it to cool and when cold pass it through the rollers a
time or two annealing it between two red hot plates under pressure and when of an even
thickness of the proposed thinness, tin in the usual way one side of the prepared gold

page_text: coated metal or metals or one side of the two prepared coating metals if desired, then
place the untinned side of one of the superior on the aforesaid red hot metal plate,
cover the tinned surface with the prepared aluminium alloy, then with the other tinned
side of the superior metal if two coats are desired in either case cover over with a
red hot metal plate and amalgamate through the calorific process the whole with
pressure, when cool thin out to the desired thinness. But by preference as follows,-
Take two sheets or flat shapes of gold coated or otherwise knitted, crotched, woven
or meshed or otherwise reticulated wire or perforated metal claimed under my
Complete Specification No. 2571 dated 15th November 1890 or similar fine thin woven
wire or plate perforated and place between them an ordinary similar sized sheet of
aluminium dental metal plate No. 5 gauge or similar size when this has been done
pass them between two suitable sheets of bright steel or iron plates bound together or
otherwise into a muffle heated to a white heat, to be heated to redness and when this
is so, withdraw the whole and press by covering with a heavy weight or other press to
consolidate the mass and when cool pass through the rollers annealing occasionaly as
aforesaid until the desired thinness has been brought about. The success of this
process depends upon the speed of passing tho materials through the several stages.
I propose also to make any of the aforesaid into flat or struck up shapes to suit the
general averages of the upper and lower jaw.
Having thus demonstrated the process of securing a substantial series of gold
coated metal plates conted on one side only or on both sides if desirable and a series
of flat or struck up dental plate shapes to attach the teeth thereto.
I then proceed
as follows: Taking the last metal first, aluminium and having selected a struck up
or a flat shape or having cut a flat shape as usual out of a gold coated
sheet of metal or aluminium metal and after having struck the same up to
the shape of the dental metal frame required, perforate with a perforating
punch or other perforating process, the margin of the plate for about half
an inch, just under where the artificial teeth are to be fixed-if desirable-
then tin over in the ordinary way with pure Russian tin with No. 4 flux and
vulcanize the teeth on the tin or prefered tin on in the usual way an additional
piece of superior dental alloy or a similar alloy or a similar superior gold coated or
other thin metal or thick leaf of gold or platinum, then vulcanize the teeth on in
the usual manner or back the teeth (if pin teeth) with the improved metalined
dental rubber as set forth in my Complete Specification No. 2571 as aforesaid in the
same manner as usual for plate teeth preserving the pins through the reticulations
and bending the pins as usual to secure them in the ordinary way and back round
with ordinary vulcanite or with the metalined rubber as aforesaid where it can be
advantageously used and finish as usual.
My invention thus consists of a series of improved qualities of gold coated metals
with special fluxes that may be relied upon for dental purposes and in a form which
will bring them within the reach of the working classes, the struggling middle classes
and the upper classes.
I wish it to be understood that I am aware that from time immemorial gold has
been coated over inferior metals both under the calorific dry process and also by
electro-deposition but these were only done for commercial and artistic purposes and
in forms which could not be employed for dental plate and similar purposes and
to have used them as so produced in their commercial and artistic combinations
would have been injurious to human life. On this account they have been properly
ignored and refused a place in dental mechanics, neither is a superior gold coated
metal or metal alloy so coated procurable in the dental metal market but only com-
mercial and artistic descriptions which are outside of the dental metal market or
depôts and to which 1 make no claim.
Having thus particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1st. The manufacture of the improved series and qualities of gold coated metals
by special fluxes substantially as and for the purposes hereinbefore described.

page_text: 2nd. The production and employment of a series of flat or partially struck up gold
coated dental frames substantially as herein before set forth.
3rd. The improved method or process of attaching artificial teeth on gold coated
metal or otherwise with metalined improved dental rubber substantially as set forth.
4th. The improved mode of backing artificial teeth with metalined rubber (after
the same manner as is done with metal plate) for the purpose of attaching them to
dental metal and similar frames and either with "metalined rubber" or ordinary dental
rubber substantially as hereinbefore described.
Dated this 18th day of November 1890.
CHARLES SAMUEL LEADBETTER.