US2335774A

US2335774A - Process for making prosthetic articles by electrodeposition of metals

Info

Publication number: US2335774A
Application number: US413494A
Authority: US
Inventors: Charles A J Landry
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-10-03
Filing date: 1941-10-03
Publication date: 1943-11-30
Anticipated expiration: 1960-11-30

Description

Nov. 30, 1943.

' rnocsss FOR MAKING rnoswrww c. A. J. LANDRY I0 ARTICLES BY ELECTRQDEPOSITION OF METALS Filed Oct. 3, 1941 Patented Nov. 30, 1943 UNITED STATES.. PATENT OFFICE PROCESS FOR MAKING PROSTHETIC AR- TICLES BY ELECTRODEPOSITION 0F METALS This invention relates to the art of makin prosthetic articles such as artificial dentures, and more particularly to those made of metal.

Objects of the invention include-the provision of a method for making metallic dentures in a simple and effective manner by applying three separateelectro-platings such that the'fit of the dentures will be very tight and therefore not liable to slipping or loosening while in the mouth; the provision of a novel and practical manner of making dentures by electro-deposition'of metals; and a method of producing strong, rigid dentures of chromium and the like.

Other objects of the invention include the provision of a method of making dentures by electrodeposition of metals and the electro-plating of areas of the dentures which are adapted to fit the natural gum or tooth contour.

Other objects and advantages of the'invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in which Fig. 1 illustrates a plaster cast of a portion of a mouth to be fitted with a plate and showing how the initial electro-plating is obtained;

Fig. 2 is a plan view of the cast after the initial plating and ready for the second plating;

Fig. 3 is a side View of the cast of Fig. 2, with a tape partially removed; and

Fig. 4 shows the plate ready for the final electro-plating.

As is usual in dentistry, an impression Of the part affected is taken and a positive cast is made therefrom. This cast can be for an entire plate, for bridgework, or for crowns. The present invention is illustrated as applied to a plate for the upper teeth, it being assumed that all the teeth have been removed, so that a cast I following the gum contour as at 2 is produced.

When the cast is finished, it is substantially covered with graphite, as by hand or in a leading machine, or by lead or other metallic foil. As seen in Fig. 1 of the drawing, the cast is illustrated as covered with graphite or lead, and apair of wire leads 3 are soldered lightly to the flat bottom of the cast, as this area provides the greatest fiat, uninterrupted area. The wires are connected with a battery or generator, and the leaded cast is placed in a copper, or other metallic bath, for a short period of time to deposit a very thin shell of the metal over the entire surface of the cast. Copper is preferable for this step in the process as it is relatively inexpensive. The purpose of this step is to apply a base metal electricity'conductor on the cast, where the conductor will provide a uniform and sure acting carrier for the current.

The cast is now removed from the bath'and the wires 3-are stripped from the bottom surface, this action also tearing off most of the plated metal from the areas near the attachment-points for wires 3, as this metal is very thin, not more than .002 of an inch. However, it will be found that the entire top and sides of the castare uniformly and uninterruptedly plated with the metal, this forming a good contactbase for the secondplating step.

Referring to Figs. 2 and 3, it will be 'seenthat lead wires 4 are laid along the sides of the'cast at the areas which are not to be built up as the prosthetic article. These wires are soldered to the metal and then covered with the masking tape 5 which is used to mask all areas of the castnot forming the denture. Wires 4 are'thereby firmly sealed to the base metal plating. Additional wires 6 are secured to the metal base at the roof portion 1 of the cast to insure proper plating current, and the cast is now ready for the second plating which forms the main part of the final denture and which is the thickest plat- After the electric deposition of about ten to fifteen thousandths of an inch on the exposed parts of the cast, the denture is formed, and this could be used as the finished product if the second plating were silver, gold, or some other metal not objectionable to the mouth. However, it is preferred to carry the process further to achieve the most nearly perfect fit possible, and this is done by stripping the leaded layer and the original base metal layer off the shell obtained in the second plating. This stripping is done by chemical means ordinarily, as by acids, or by any other convenient or desired means. This of course leaves the prosthetic shell, plate, or crown by itself in substantially finished condition.

The stripped prosthetic shell is then wired in any convenient manner as generally indicated in Fig. 4, and returned to the plating bath for the third and final deposition of metal on all surfaces thereof, both on the fitted surfaces 8 and the wearing surfaces. This plating should be about .001.004 of an inch and is sufficient to build up the fitted surfaces enough to provide a very tight fit in the mouth, and it will be seen that the third plating conforms to the cast I and will render the shell thick enough on its fitted surfaces to closely embrace the gums. This plating may be done or repeated years after initial formation of the denture to take care of gum shrinkage, etc., and in the first instance will replace the stripped graphite or lead and underlying base metal thickness plus adding a small extra thickness for the closer fit above described.

A variation of the process described is contemplated in the manufacture of chromium plates, bridges, etc. Chromium gives an agreeable taste to the mouth, but is a difiicult metal of which to form electro-deposited prosthetic articles of the nature herein described.

After the base metal or first plating, the cast is prepared as described and as shown in Figs. 2 and 3, and is placed in a nickel bath, wherein a solid plating about eight to ten thousandths of an inch is deposited. Then the cast is removed fro the nickel bath and placed without change i in a chromium bath to plate the wearing surfaces, which of course are the exposed surfaces, with a substantial layer of chromium. The cast is removed from the chromium bath, stripped of the graphite or lead and underlying base metal or first plating as before, and the entire shell as in Fig. 4 is given an additional chromium plating corresponding to the above described third plating.

The nickel-chrome denture is extremely strong, rigid, and long lasting, and is provided with a relatively thick chromium plate on all wearing surfaces with a thinner chromium plate on the fitted surfaces; the nickel core or center imparts strength to the denture, and the chromium is more easily deposited on the nickel than on copper. In some cases, it may be desired to use a Ni-Chrome bath in place of the nickel bath, and this also is contemplated in the invention.

Having thus described my invention and the advantages thereof, I do not Wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. The process of making prosthetic articles by electro-deposition of metals including the steps of providing a cast of the member affected, applying a base layer of electric conducting material throughout said cast, masking parts of the cast not defining the member to leave exposed those parts of the cast defining the member, electro-depositing a heavy nickel bearing metal layer on said exposed parts, electro-depositing a layer of chromium bearing metal on said nickel bearing metal layer, stripping the base layer from the article, and electro-depositing a chromium bearing metal layer throughout the entire surface of the article for obtaining a close fit at the areas which have been stripped.

2. The process of making artificial dentures by electro-deposition of metals including the steps of providing a cast of the mouth, applying a thin layer of electric conducting material to all surfaces of said cast, electro-depositing a thin layer of base metal of low electric resistivity to said first named layer, masking the cast to leave the parts corresponding to the affected parts of the mouth exposed, electro-depositing a heavy layer of a nickel bearing metal on said exposed parts thus forming both wearing and fitted surfaces of said denture, said wearing surfaces being exposed and said fitted surfaces being next to the cast, electro-depositing a further layer of a different metal on said exposed wearing surfaces, stripping said base metal layer from the article, and electro-depositing a still further metal layer on both wearing and fitted surfaces of the stripped denture, said last named deposit being made thicker than the thickness of said stripped base metal thus obtaining a close fit at the stripped areas.

CHARLES A. J. LANDRY.