US1825286A - Denture - Google Patents

Description

Patented Sept. 2 9, 1931 UNITED STATES PATENT OFFICE ELMER .ROBEBTS, OF MONTCLAIB, NEW JERSEY, ASSIGNOR TO THE NAUGATUCK CHEMICAL COMPANY, OF NAUGATUCK, CONNECTICUT, A CORPORATION OF CON- NEOTIGUT DENTURE Io Drawing.

This invention relates to a denture, more particularly to a denture made from a heat settable plastic.

In dental work many materials or compositions have been utilized for the making of artificial dentures, but up to the present time they all are objectionable in one or more respects. Dentures made of gold and other metals and alloys are objectionable because the final casting is not easily fitted and the metal is very expensive, and in addition the use of gold is sometimes objected to on account of too great thermal conductivity. One of the commonest materials used for dentures is hard rubber, but this is objectionable. since it'is impossible to properly match the color of the human gums reason of lack of translucency in the rubber, repairs and alterations, cannot be made without to some extent over-curing the orignal part of the denture, and the hard rubber is not a hygienic material. Use has also been made of phenol-aldehyde resins, such as bakelite, but it is difiicult to secure a uniform cure, the color shade is not permanent, especially in making a second cure on repairs, and the shattering strength of the material is relatively low. Various pyroxylin com ounds have also been proposed, such as celluloid, but they are unsanitary and the taste is objectionable.

An object of my invention is to, provide an improved denture closely simulating the natural color of the human gums, which is easy to repair or alter Withoutinjury to the original portion, which is sanitary and does not propagate bacteria, which is unaffected by heat, cold, moisture or dryness, which is inert tothe alkalies and acids occurring in the human mouth, and which has a good shattering strength.

For a complete disclosure of the nature and objects of the invention, reference is had to the accompanying specification and claims.

It has been known for a long time that styrol, C H .CH:CH can be polymerized to a resinous polymer, but this polymer in general is relatively brittle, is more or less colored and is of little practical value.

Application filed Febriiary 9, 1929. Serial No. 338,881.

However, it has been recently discovered that by certain methods of polymerization a pure styrol polymer can be obtained which is transparent and water white in color, and is relatively tough and hard. This material can be readily molded under heat and pressure, it can be compounded with desired filling and coloring materials, and by reason of its water white color, it is possible to exactly match difierent batches of colored material by using the same amounts of the desired coloring. One method of obtaining it is disclosed in patent to Ostromislensky, No. 1,683,402, and he has termed it alpha meta styrol.

I have found that this material is particularly adapted for use in the making of artificial dentures. In the making of such dentures the required operations are simple and 'in general similar to those previously employed. As an example an impression is taken in the ordinary way and a denture with porcelain teeth is thereafter set up and molded, the base portion of the denture being 'formed of wax with the roots of the teeth embedded therein. The wax denture is set in a two part plaster of Paris mold, the line of division between the two parts being such that the body portions of the teeth are in one section, and the root portions of the teeth and the wax denture are substantially in the other section. The line of division between the sections may be maintained dur ing casting by the use of soap or other suitable material. The plaster of Paris sections are backed up by metal in order to withstand the pressure during moldingpf the styrol. The wax is then melted out, the two plaster of Paris sections opened up, and

the cavity formerly occupied by the wax is When cold the plaster is removed and the denture oiished and finished as in the case of a har rubber denture.

By the use of the polymerized styrol the molding operation is simply and easily carried out, the styrol denture reproduces with great fidelity the contours of the mold, owing to the transparency of the. styrol the natural more or less translucent color of the human gums or mouth can be readily simulated, repairs and alterations can be very simply made and without any injury to the old portion by the re-heating, the styrol is sanitary, has the required shattering strength, and it is unaffected by any of the conditions to which it is subjected when in use.

In place of polymerized styrol any suitable1 polymer of styrol homologues may be use Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. As a new article a denture comprising a tough polymerized styrol.

2. As a new article a denture comprising tough alpha meta styrol.

3. As a new article, a denture comprising a tough polymerized styrol which is substantially free of unpolymerized styrol.

Signed at New York, county and State of New York, this 8th day of February,

ELMER ROBERTS.