US173647A - Improvement in dental molds - Google Patents

Description

UNITED STATES PATENT OEEIcE.

ABRAM T. -KEIGHTLEY, OF GREENGASTLE, INDIANA.

.IMPROVEMENT IN DENTALl MOLDS.

Specification forming part of Letters Patent No. 173,641?, dated February 1.5, 1876; application filed December 31, 1875.

To all whom it may concern.-

Beit known that I, ABRAM T. KEIGHTLEY, of Greencastle, in the 'county of Putnam and State of Indiana, have invented a new and valuable Improvement in Stamping Teeth on Celluloid Plates; and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the 4same, reference being had to the annexed drawings, making a part of this specification, and to the letters and figures of reference 'marked thereon. A Figure l of the drawings isa representation of a side view of my stirrnp, With-the mold vertically sectioned 5 and Fig. 2 is a plan view of the mold.

This invention has relation to a preparatory 'process for securing teeth on celluloid plate,

used by dentists in the manufactureof sets ofteeth for practical use.

The nature of the invention consists in so securing the plaster ,of the upper mold, when placed in the Hask, by a metal ring that expansion of the mold while under pressure is effectually prevented, as will bemhereinafter .is taken, this cast is covered with a thin plate of wax, which is made to conform properly to the surface. Uponthis the selected teeth are placed in order, banked up with wax, to imitate, as nearly as possible, the fullness of the natural gum around the teeth. -When this is completed, and while yet on the mold, a reverse cast is taken of teeth, wax, and all.

' The first mold, underneath is now. removed,

leaving wax, plate, and teeth attached to the second or uppermost mold. The wax is now melted away, leaving the-teeth clean, and embedded in this last mold in the required position for the next process, with the rivet ends,

or roots,7 projecting above the molded surface. At this point the first cast is placed in the liask and secured. A blank of celluloid is then laid over it, the second mold containing the teeth is placed exactly upon this, the flask' put in position, and all placed in the stirrup and in the heater. As the heat softens the celluloid blank, the upper mold is slowly and constantly brought down by a screw in the stirrup acting on the follower Vof the flask. This gradual pressure stamps or embeds the teeth in the celluloid so firmly that no ordinary usage can dislodge them. 1f thepressure is ,applied too rapidly or exceeds afcern tain limit, the .upper mold expands, so as to break or utterly ruin the teeth. It is this frequently-recurring mischief which my invention is designed to prevent, and it is effected in the following manner:

Referring to the letters and figures of reference, A, Fig. l, represents the lower and B the upper molds, between which the celluloid and teeth are pressed. When the Wax andl teeth are placed in position on the lower mold,

they are secured in the iask by filling in with plaster, in the usual Way. The metal ring or band a, preferably made of tin or zinc, the ends of which are usually `joined by a lapseam, is placed on, surrounding the teeth at a quarter of an inch, more or less, distant from them, and resting on the prepared surface of the mold at b, and nearly even with the lip of the lower flask c, as shown in Fig. 1. The

band, which is left embedded in the upper mold, becomes aprotection to it, and prevents any expansion or lateral displacement, that often occurs by virtue of the wedge-like formation of the entire tooth-arch, as it gradually sinks by pressure into the celluloid, which 4itself must conform to the outwardly-inclined angle of the lower mold, as shown at f. This stantialljr in the manner and for the purpose ring,T or band is applicable to the protection of specified.

"molds for lower as well as upper sets of teeth. In testimony that I claim the above I have What I claim as new, and desire to secure hereunto subscribed my name in the presence by Letters Patent, isof two Witnesses.

A metal band or ring embedded iu the plasi ABRAM TIMOTHY KEIGHTLEY. ter around the teeth, to prevent expansion of Witnesses: the same when pressure is applied in stamp- WM. HILL,

ing or setting the teeth in Celluloid plate, sub- L. E. BOSWELL.

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