US909696A - Process for molding tooth-crowns and the like. - Google Patents

Description

S. SHIMURA & Y. MINAGAWA.

PROCESS FOR MOLDING TOOTH OROWNS AND THE LIKE.

APPLICATION FILED DEC. 16, 1907.

909,696, Patented Ja11.12,l909.

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WITNESSES INVENTORY S. SHIMURA & Y. MINAGAWA.

PROCESS FOR MOLDING TOOTH CBOWNS AND THE LIKE.

- APPLICATION FILED DEO.16, 1907.

909,696. I Patented Jan. 12, 1909.

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SEIMARO SHIMURA AND YOSHIZO MINAGAWA, OF TOKYO, JAPAN.

PROCESS FOR MOLDING TOOTH-GROWNS AND THE LIKE.

Specification of Letters Patent.

Patented Jan. 12, 1909.

Application filed December 16, 1907. Serial No. 406,820.

T 0 all whom it may concern:

Be it known that we, SEIMARO SHIMURA and Yosnizo MINAGAWA, subjects of the Emperor of Japan, residing, respectively, at No. 20 Gofuku-cho, N ihombashi-ku, city of Tokyo, Japan, and at No. 6 Tomizawa-cho, Nihombashi-ku, city of Tokyo, Japan, have invented new and useful Improvements in Proc esses for Molding Tooth-Crowns and the Like; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object consists of obtaining a perfect occlusion, securing thereby a permanency of the cusps in crowns and bridges and also obtaining a perfect and easy fit of the gold inlays.

Figure 1 shows a perspective of one of the half boxes used as a part of a mold for carrying out our invention; Fig. 2 is a perspec tive of the other half mold; Fig. 3 is a perspective of the mold complete; Fig. 4 is a section showing the channels for facilitating the pouring of the molten metal.

In order to make gold tooth crowns provided with cusps and bridges, we proceed as follows: l/Ve first fit in the ordinary way, a gold band in the patients mouth, and place opposite this band, that is, upon the opposing jaw, a piece of softened modeling composition, and then squeeze the latter between the jaw carrying the band, and a tooth in the other jaw and opposite the band. An impression is made conveniently by closing the teeth together so as to secure an impression from the tooth opposite the band. The composition is now allowed to stand and is removed together with the band. The composition member is now trimmed and smoothed down with cuttle fish disks or other mechanical appliances, and is next separated from the band. We will designate the member thus completed, as the pattern. We next take the two-part mold (see A, B, Figs. 1 and 2) and fill the half A with a thick creamy paste consisting of one part plaster of paris and two parts oxid of lead.

The face of the paste being smooth and fiush with the upper surface of the part A, the pattern is forced partially into the paste, as shown in Fig. 4, a portion of the surface being left exposed and protruding slightly from the paste. The paste is now allowed to dry, whereupon it becomes hard. The entire surface is now given a thin coating of oil or varnish. The part B of the mold is now filled with the same kind of paste and the two members A and B of the mold are placed face to face and secured together as indicated in Fig. 3. The entire mold and its contents are now warmed and the member B carefully removed. The pattern is next taken out and the paste is out slightly so as to form channels 5, the latter registering with the semi-circular openings 0, c, in the two parts of the mold. The two parts of the mold are next placed together and are sealed all around with the mixture, the channels I) being left face to face so that there is a clear opening through the paste, this opening being substantially funnel shaped in order to facilitate pouring the molten metal into the mold. The entire mold and its contents are now dried by the aid of a gas blower, and when completely dry, molten gold is poured into the mold through the funnel shaped opening. The gold is melted in a crucible made for the purpose.

lVhat we claim is as follows:

The process herein described, of molding artificial teeth and the like, which consists in forming a model of the article to be molded, preparing a plastic mixture, filling said plastic mixture into a half box, insert-' ing said model partially into said plastic mixture, allowing said plastic mixture to harden, oiling the surface of the hardened mixture, then filling another half box with plastic composition, next placing the two half boxes together so that said model buries itself partially in the mixture held by the half box last prepared, next warming the two half boxes and their contents, next separating the two half boxes, removing the model, cutting channels from the exterior of the half boxes to the cavity formerly occupied by the model, and pouring through said channels into said cavity the materials to form the artificial teeth.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

SEIMARO SHIMURA. YOSHIZO MINAGAWA. l/Vitnesses:

J AMES B. DAVIES, LELAND HARRISON.

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