US2070771A - Denture - Google Patents

Description

'Feb. 16, 1937. w ART'ZT 2,070,771

7 YDENTURE Filed April 26, 1935 4 Sheets-Sheet 1 M INVENTOR. By Ma/W F ATTORNEY.

Feb. 16, 1937.

W. ARTZT DENTURE 4 Sheets- Sheet 2 Filed April 26, 1.935

IN V EN TOR.

A TTORNEY.

Feb. 16,1937. w. ARTZT v ,07 ,77

DENTURE Filed April 26, 1935 4 She'ts-Sheet a Fg'I-O INVENTOR.

A TTORNE Y.

4 Sheets-Sheet 4 W61 BY ATTORNEY,

Patented Feb. 16, 1937 UNITED STATES PATENT OFFICE 7 illaims.

This invention relates to the art of constructing dentures, and is of important value in connection with both full plates and so-called partials, uppers and lowers. By the present invention there is provided not only an improved denthe invention has the following, among other,

objects:

(I) To provide a denture including a metal component of a superior type, and yet of lighter weight and consequently less gold or alloy cost than any previously known metallic component corresponding in type thereto, that is, for instance, in the sense that the two metallic components compared are palate-impinging walls or sheets (for full upper plates), or are inner-gumfacing tabs or webs (for-full lower plates).

(II) To provide not only a denture as described under (I), but also one, wherein the new metallic component is so inseparably bonded to the plate portion or portions which carry the teeth that theentire plate is in effect a single unitary integral structure, and, consequently, one of greater strength than heretofore, one of higher sanitary type than heretofore (because no cracks or crevices for the lodgement of tartar or bacteriabreeding food particles are present when the denture is completed for delivery to the wearer, and, as will be clear from the clause following, no cracks or crevices will later develop), and one of longer life than heretofore because all parts a of the denture are not only inseparably bonded as above stated but joined in such manner and with such interior interlockings and exterior smooth blending of contours that the minutest break or crack even at the superficies of the denture cannot occur.

(III) To provide a denture having the advantages aforesaid, and one which has the metallic component aforesaid extended continuously over the lingual surfaces of the gum toward and to the true ridge-line of the gum.

(IV) To provide a denture having some or all of the above mentioned advantages, wherein, when such denture is a full or substantially full upper plate, that is, when such denture is an 0 upper one including said metallic component .or a part thereof as a palate-impinging wall or sheet, such wall can be of such extreme lightness and thinness, and of such free heat conductivity, that, while exceedingly strong, not only will it cling closely and with velvety comfort to the roof of the mouth, but it will at the same time be of unusual thinness.

So far as providing a new and valuable metho of and apparatus for producing an improved denture is concerned, the invention has the following, among other, objects:

(1) .To provide a quicker, more convenient and less expensive method and apparatus than heretofore for the production of a superior kind of metal-type upper or lower plate or other denture.

(2) To provide, and this particularly has to do with lowering the cost of the method of fabrication and consequently the cost of the denture itself, a method entirely eliminating the previously deemed essential steps of making, after a plaster impression of the patients gums and/or mouth-roof is produced, and a reverse or true casting of artificial stone is obtained from the said plaster impression, the wax pattern or base for try-out in the patients mouth, and fitting such pattern.

(3) To'provide, in this last connection, a tryout pattern or base which when first placed in the patients -mouth includes said metallic component, or a stratic, laminar or other element participating in the structural entirety of said component, and with this portion of the structure so accurately modelled to the mouth interior that a perfect fit at the first trial may besaid 'to be almost inevitable. The importance of this object cannot be over-emphasized, as wax can be molded with but limited fidelity to the irregularities of any non-uniplanar molding or shaping surface. In such wax type of try-out pattern or cast,'to which the art has heretofore been limited, a dentist-has never been able to tell beforehand whether a try-out pattern will even approximately fit. That is why in fitting a dentureunder present practice a large plurality of impressions, carvings and recarvings, local moldings and remoldings, and even complete makeovers, are required. Of the dentures being fitted today, investigation shows that 35% require one .or more complete make-overs.

i) To provide a method and apparatus for the securement within a denture of a rod or barlike reinforcement and interlock, and/or a rigidifying and strengthening element in the nature of a flange bent from an edge or marginal metal portion, which is'or are so present that it or therecan never be a cracking, splitting or other. weakening element in the. denture.

(5) To provide a method and apparatus for the production of a denture having some or all ofthe advantages above listed, and one wherein the metallic component aforesaid can be laminar in character yet with its striae so interbonded that, in effect, there is but one single thickness of metal-even though, as is now preferred, the aforesaid rod-like, bar-like or equivalent reinforcements and/or interlocks are wholly or partially nested between two of such striae.

(6) To provide a method and apparatus as last above described, wherein, when advisable, said metallic component may in one portion consist of a given number of striae and in another portion consist of a greater number of striae.

(7) To provide a method and apparatus having some or all of the advantages aforesaid, and one wherein said metallic component, but preferably one of the laminae thereof referred to in (6), and in this case desirably the one thereof to be uppermost when the denture is finished, is, incident to its shaping, cut or indented along a substantially scalloped line to define a substantially saw-tooth boundary along a general line of extension which is substantially of horseshoe shape, and in such fashion that the marginal portions of the plate or of the lamina just mentioned are shaped or may be shaped to conform to and cling closely against the gum below, and between (and outwardly beyond) the lingual sides of, the teeth.

(8) To provide a method and apparatus wherein the plate includes a metallic marginal portion so shaped as to be capable of being laid to cover the gum opposite, and between (and outwardly beyond), the lingual sides of the teeth, wherein such marginal portion is of a material substantially as flexible as gold or a suitable gold alloy, and wherein a plurality of suitable reinforcing and stiffening addenda are suitably secured to the upper surface of the plate at/or adjacent to some or all of the points along said marginal portion where the latter is shaped to present preferably pointed projections for extension toward overlying the gum between contiguous pairs of teeth.

(9) To provide a method and apparatus for the production of a denture having a metallic component incorporating some at least of the advantages aforesaid, yet one wherein said component or its incorporated sheet-like elements is or are shaped or formed by pressing or squeezing dies, yet one wherein high squeezing pressures, such, for instance, as would be provided by an hydraulically actuated press, are entirely avoided.

The above and other objects and advantages of the invention will be hereinafter more fully explained, or become apparent as this specification proceeds.

The making of metallic-content dentures of a satisfactory kind and at comparatively low cost has long been the desideratum sought by mechanical dentistry. Such a metallic-content is especially valuable in connection with full uppers and lowers, and while highly advantageous in the latter, is probably of prime utility in the former. The noble metal gold, or a noble metal alloy containing gold, such as the familiar one or gold, silver and palladium, is now favored. Consequently, in aid of brevity yet clarity of exposition, but with no limitation to be taken therefrom, the present invention will be described in detail in connection with gold; and wherever gold is mentioned from this point on in this specification proper, or in the claims appended, there is meant either gold of a suitable degree of fineness, or the alloy just referred to, or some equivalent metal or metal alloy.

Before proceeding with such detailed descrip tion, it may be well to emphasize the importance in the art of the general method to the improvement of which this invention is directed. In this connection, and from this point on in this specification and until toward the termination thereof a discussion of the present invention in regard to the making of lowers is taken up, and again for brevity yet clarity of exposition, uppers only will be referred to.

In such an upper, the sheet or wall structure aforesaid has come to be referred to in the art as the plate, and such nomenclature will be herein followed. Such plate has heretofore been attempted to be formed by other methods than that just mentioned asthe general method to the improvement of which this invention is directed. Said other methods have been either a casting process, or a true swedging or hammering process. Both have heretofore been proved absolutely impracticable. As to the casting process: Gold or an alloy of the kind required has not the requisite fluidity and/ or other attributes to permit its flowing fully into all the minute and individual moldcavity formations required to give a perfect fit to the plate; that is, when molten gold or an alloy of the kind just referred to is poured into the mold it fails to penetrate fully into all the cavity extensions thereof, particularly where narrow crosssections are present and/or when taking its congelation set it fails to reproduce precisely every pecularity of all cavity portions. Furthermore, bubbles practically always form at the plate surfaces of greater area, and these must be removed and the remaining bubble-film-edges must be filed away, with the result that high hand-labor cost is entailed and yet a perfect fit is almost impossible. Indeed, attempts to use this process have practically everywhere been abandoned. As to the true swedging or hammering process: Aside from the difficulty of providing accurate male and female shaping anvils,

, the hammering or peening step itself results in intolerable distortions. The reverse side of the plate to that which is being hammered may possibly become reformed truly to correspond with the shaping portions of the anvil being employed, but gold is comparatively soft and consequently is somewhat compressible, indeed, as is Well known, is one of the most malleable of metals, and even when the great expense of providing both a male and a female anvil is incurred, one or the other of the two faces of the plate will be found to be undesirably distorted. As a matter of fact, this process, too, is seldom if ever resorted to.

The method to the improvement of which the present invention is directed is the process of fabricating the plate in shaping or forming dies, that is, by the utilization of a squeezing pressure. Before describing the present improvement further, it may be well to give a rapid rsum of the ordinary method of making an upper denture and one including a gold plate as wellas a horse-shoe shaped carrier for the teeth formed wholly of vulcanized rubber or some equivalent heat and/or pressure settable plastic material, as such method is now generally practised. The steps of this method are, sequently, substantially as follows:

(a) A plaster impression is made in situ. That is, a wet plaster packed about the upper gum and the roof of the mouth, is allowed to set and is removed.

(b) A stone model is made. This is a replica of the plaster impression, obtained by a procedure well known in the art. Such model,with the mouth roof container uppermost, is shown at c in Fig. 3 of the accompanying drawings.

(c) A Wax cast'or try-out denture is made. This is made on said stone model and handmodelled and carved thereon to a shape satisfactory to the artist-artisan at work and the teeth are set therein as shown in Fig. 3. V

The wax cast thus obtained is removed from the stone model, and tried out in the patients mouth.

(d) A zinc die for the shaping of the under surface of the gold plate is now made. .To obtain this molten zinc is poured into amolding cavity thereof, established by using the stone model as a pattern. (At this point it may be explained that this zinc die is never finely accurate, due to the fact that the cavity in the sand'cannot with perfect fidelity reproduce the contours of the stone model.) (e) A lead counter-die for the shaping of the upper surface of said gold plate is next made. This counter-die is obtained by casting molten zinc against the zinc die.

(f) The blank required to form the gold plate is provided. The gold plate is sawn or otherwise cut to the familiar shape, as shown at f in Fig.

I of the accompanying drawings.

(y) Such gold plate blank is shaped. The blank is placed over the die and under the counter-die, and these stacked parts are"swedged, or, actually, subjected to pressure in the direction of the stack. In View of the fact that a single solid plate is used, and is generally of 28 gauge thickness, the pressure required is very high; and is generally hydraulically applied, often to the extent'of tons of pressure per square inch. (At this point it may be explained that such a high pressure is fatal to accurate fitting of the plate where it is to lie tightly against the mouth-roof contours, as the high pressure having to be applied breaks down the high points of the die and counter-die before the plate is finally shaped as predetermined.)

7 (h) Mushroom anchors are. secured to the plate. Usually ten of these are used; arranged as shown at (h) in Fig. 1.

(2') The plate is secured .to the proper part of the wax cast obtained according to step' (c). This cast has up to this point been constituted as shown in full lines in Fig. 2, the teeth being indicated at t and the wax at'w. The central wax mass is cut away along the dot-and-dash line .9, leaving a horse-shoe shaped portion as shown at 10'. As shown also in Fig. 3, the finally assembled plate, mass of wax w and teeth are obtained by laying the shaped plate :0 on the stone model 0, obtained according to (0) above, and then hand-squeezing the softened wax mass 20' in place as shown, to embed the enlarged heads of the mushroom anchors h in the wax.

(7') The teeth of the denture last referred to are invested in plaster. The plaster is applied to the sides of the teeth and the undersurface of the gold plate, and the sides of the gum. After the plaster sets, and removal of the wax, a molding cavity for shaping vulcanizable rubber or the like substitute for the wax is provided. In other words, there is provided whatfmay be termed the cope'or lower half of a split horizontal mold for said rubber.

I (k) The complementary drag for the cope just abovediescrib'ed-is' prepared. This dragis made of artificial stone, cast therefrom by the aid of the cope in a manner well understood in the art.

(Z) The wax in the cope is washed ou (m) The rubber substitute for the wax is set in place and vulcanized. The drag is replaced over the cope, following packing in of the rubber material to fill the cavity formed by melting out of the wax.

The accompanying drawings, particularly so faras Fig. 4 and the higher numbered views are concerned, illustrate, but not by way of limitation, a denture embodiment of the invention as now preferred, and a now favored method of and apparatus for producing such denture.

In said drawings, wherein similar. reference characters represent similar parts throughout the several views,

Fig. 1 is abottom plan view, partially broken away, of a gold-plate incorporating denture of the kind heretofore generally made;

Fig. 2 is a view similar to Fig. 1, showing in full lines one stage in the manufacture of the denture last referred to, and showing 'in broken lines a later stage in the manufacture of said denture;

Fig. 3 is a'lateral vertical section taken through Fig. 4 is a bottom plan view, partially broken away, of a denture constituting a now preferred embodiment of the presentinvention;

Fig. 5 is a top plan view.on an enlarged scale,

of such denture; Fig. 6 is a similarly'enlarged bottom plan view of the gold plate of said denture, the positions of the teeth being indicated in dot and dash lines; Fig. 7 is a perspective view, on a still more enlarged scale, of said plate, arranged upside down relative to its normal position in the mouth, that is, showing the mouth-roof-embracing lamina or palatal sheet of the plate lowermost;

Fig. 8 is a side elevation of said plate, as seen when looking away from the observer in Fig. 7;

Fig. 9 is an enlar-geddetail in perspective;

Fig. 9a is a similar view,but even more enlarged; I

Fig. 10 is a vertical section, taken on line lill0 of Fig. 9;

Fig. 11 is a vertical sectional view, illustrating an early step in the manufacture of said denture;

Fig. 12 is a similar View, illustrating a later step-the parts shown in Fig. -11 being here shown in dot and dash;

Fig. 13 is a similar view, illustrating a still later step,-the parts shown in Fig 12 being here shown in dot and'dash; V b

Fig. 14 is a similar View, illustrating subsequent steps,-the lowermost parts shown'in Fig. 11 being here shown at the lower part of the view;

Fig. 15 is a similar view, showing alater step,- certain parts shown in full lines and in dot and dash lines in Fig. 14 being here shown in dot and dash lines;

Fig. 16 is a similar view, showing still a later step,the parts shown in full lines in Fig. 15.

Fig. is a top plan view of the completed denture last mentioned.

Referring now in detail to Figs. 4 to 10 (Figs. 1, 2 and 3 having been described hereinabove in the introduction to this specification), the embodiment of the invention which is shown includes a gum of vulcanized rubber or a suitable substitute composition, in which teeth 26 are set and anchored in any known or satisfactory way; and a metal plate the elements of which, as here shown, are a pair of main shells or sheets 27 and 28, an intermediate shell or sheet 29, a reinforcing means for said lower sheet, C-shaped pillars or strut-like spacing and bracing members 3| for sheets 21 and 28, and a plurality of anchor-devices one of which is shown at 32. I

Sheet 21 is the palatal sheet and is shaped to fit suction-tight against the roof of the mouth, and sheet 28, over its main portion conformingly shaped, is the basal sheet. This sheet 28, however, is preferably further very carefully shaped around its marginal portions which follow the gums of the patient so as accurately and completely to cover the gum portions at the lingual sides of the teeth. As a result, the sheet 28 is here shown as having a scalloped margin, presenting pointed projections like those shown in Figs. 7 and 8 for entering the spaces between the teeth. At each or most or some of these projections, the anchor-devices 32 above referred to are mounted.

In making up this plate, the gum-following edge of sheet 21 is turned up or marginally flanged, as here shown at 21a, and the reinforcing means 30 (in the present case a length of half round wire about wide at its flat ,side) having been shaped to include a plurality of suitably placed and shaped loops 30a and terminal hooks 30b, this means 30 is fitted tight on the inside of such flange 27a and soldered in place thereagainst; the parts of said flange opposite the openings of the loops being pincer-squeezed down flat as shown at 27a. Next the intermediate sheet 29, now shaped to permit that, is soldered to the sheet 21 so that the meeting faces of both sheets are cohered all over. Next the anchor-devices 32 are soldered on the sheet 28, now shaped to permit that. Finally, the sheet 28 is soldered to the already cohered sheets 21 and 29, so that the meeting faces of sheets 28 and 29 are cohered all over and so that the meeting faces of sheets 28 and 2'! (forward of the sheet 29) are cohered all over up to about the dot and dash line 33 of Fig. 5; that is, the plate is now of two laminae in one part and of three laminae in another part, and is integrated into a unitary gold structure between the rear edge of the plate (marked 34 in Fig 5), and said dot and dash line 33; but forward and to each side of said line 33 the plate carries an outwardly flaring concavity for the accommodation of vulcanized rubber or the like for the final gum.

Aside from the details just given, and in order to provide for proper shaping of the sheet elements of the plate, and particularly for the accurate shaping of sheets 27 and 28, the preferred way of carrying out the invention is to proceed as follows:

(A) A plaster impression is made exactly as described under (a) above.

(B) A stone model is made exactly as described under (22) above. But from then on the present method differs radically from prior practice,

viz:

(0) The stone model is not employed for the making of a wax pattern or cast, as explained under (0) above, but instead it is built up with artists clay to provide a flat-topped and vertically stepped extension as shown at 35 (Fig. 11).

(D) A flask 36 is placed on the model, and a suitable casting metal, preferably invar or another suitable alloy having a very low coefficient of expansion, is poured molten into the flask to provide, when set, a metal die 31 (Fig, 12).

(E) Die 31 is now turned upside down, and over the flask 36 is placed a flask 38, and a suitable casting metal, preferably the same metal referred to under (D), is poured molten into the flask as 38, to provide when set, a metal counterdie 39 (see Fig. 13).

(F)-(I) Between said die and counterdie (which, it will be understood, are to form therebetween the mouth-roof matching sheet 21 of the plate, since the stone model 0, except for the extension 35, is a replica of such roof-mouth) is placed a comparatively thin gold sheet, previously cut approximately tothe correct size. The thus stacked parts are subjected to a squeezing pressure in the direction of the stack. It is only necessary then to separate the die and counterdie and remove a perfectly and finally shaped sheet 21. Excellent results have been obtained when the sheet, including a layer of gold solder all over (such layer being shown at 21" in Fig. 9a) is of 30 gauge thickness. Hydraulic pressure is not used, but merely such hand pressure as is given by placing the stacked parts between the platens of an ordinary old-fashioned type of ofiice letter copying press, and turning the screw fairly tight. The high points of the die and counterdie are not injured. Yet, due to the vertical inner face of extension 35, as shown in Fig. 11, the die and counterdie coact in such manner that they bend up the edge of the plate 21 as already described to form the flange as shown at 21a.--

(II) Theintermediate sheet 29 is made by first cutting the same from a 34 gauge gold sheet to approximate shape, and then placing this blank properly between the die and counterdie, and subjecting the thus stacked parts to pressure as just above described.The pressing, finishing and polishing of each of these sheets occurs at a single operation.

(G) The partially complete gold plate (now including the integrated sheets 21 and 29, the soldered-in-place reinforcing means 30, and the crimpings 21a of the flange 21a. of the plate 21) is laid on the stone model 0, and, for the first time, the wax pattern or cast is made. This pattern or cast is made on top of said partially completed plate, as shown at 40 in Fig. 14; and the teeth 28 are set in place. The resulting temporary denture is tried in the patients mouth, and, .as I have found, the same always has a perfect fit following care in the preparation of impressions and models.

Next the final sheet element, the sheet 28 is made; the procedure being preferably as follows:

(H) Said temporary denture is reset on the model 0, as in Fig. 14, and an artists clay addition is cast in situ as shown in dot and dash line at 4|--this clay being modelled upwardly to lie all over the exposed buccal sides of the teeth up to the points of maximum outward swells thereof.

(I) As soon as said clay is set, the temporary denture is removed from the stone model of Fig. 14, and, as shown in Fig. 15, said denture is used as a molding instrumentality, to provide a casting cavity in a mass of wet and plastic artificial stone 42 placed in a flask 43. Because of the artist's clay addition 4| applied according to (H) the said denture can be withdrawn easily and without injury thereto, from the molding cavity established by it in said artificial stone when said stone has set. 1

(J) As soon as said stone sets, a flask 44 is set on flask 43, and a suitable casting metal, of the kind referred to under (D), is poured molten into flask 44 'to provide, when set, a metal counterdie 45 (Fig 16).

(K) Using the stone 42 of Fig. 15. as the die for the counterdie 45, between the die and counterdie there is placed another gold blank cut to approximate size, as by hand shears, from a gold sheet of 30 gauge thickness. The thus stacked parts are subjected to the'same comparatively low squeezing pressure as described above under (F), and the sheet 28 is thereby produced; also formed, finished and polished at a single operation. Even the scalloped edge establishing the pointed projections shown in Figs. 7 and 8 are finely finished, if the die and counterdie are carefully made, and particularly if the die is present, not as a stone 42, but as an invar or similar metal replica thereof; or the outline of this scalloping is, by the pressing operation aforesaid, scribed or scored in the blank 28 incidental to its shaping, so that a hand shears trimming operation requires but a few seconds.

(L) The temporary denture made as described above under (G) is now placed again on the stone model as shown in Fig. 1'7, and is enveloped in plaster of Paris as shown in Figs. 17 and 18 to provide a cope 46. As soon as this plaster is set, the cope is sawn through as shown by the dot and dash line 41, whereupon it may be readily split in half along the dotted line 48.

(M) These cope parts, now having the teeth invested therein, are lifted off and away from the stone model 0; and the wax 40 is heated and melted out. Then, the sheet 28 having been equipped with anchor-devices 32 (Fig. 8), and having been soldered to the previously solderedtogether sheets 2'! and 29 as hereinabove described under (F), and the pillars or struts 3| having been soldered to the sheets 2! and 28, the finally completed gold plate is reset on the stone model, and vulcanizable rubber or a suitable substitute is packed into the outwardly flaring cavity presented between the plates 21 and 2B and into the space formerly occupied by the Wax 4U, incidental to reassembling the gold parts on the stone model and replacing the cope parts around said model. Heat and pressure are applied to this rubber or the like, and when the latter is vulcanized or otherwise set, the denture is completed.

It will readily be seen that a more comfortable, stronger and less expensive denture is provided than heretofore; and one, moreover, when of the type just described, where 6 to 8 pennyweight of gold is' required as against 12 to 16 pennyweight in any denture having an equivalent gold superficies.

Very many possible other embodiments of the invention could be described, but this specification would run to inordinate length.

However, one now preferred form of full lower denture, and a now favored method and apparatus for fabricating same, will be explained.

Refer in this connection to Figs. 19 and 20, the procedure being as follows:

In the usual way, a stone model is made from a plaster impression of the lower gum, thismodel being shown in Fig. 19.

Over this model, a flask' is placed as in Fig. 12, and invar or other suitable metal die is. made as described under (D) above-the counterdie to cooperate with which is said stone model.

Then a suitably shaped blank from a 34 gauge gold sheet is placed between such die and counterdie, and pressure applied as above, this giving a shell as shown at S in Fig. 19.

Said shell is, preferably after being equipped within its trough with suitable anchor-means, such, for instance, as a plurality of those shown at 32 in .Fig. 8, placedon the stone model 0'. and there is shaped thereon a wax gum and the teeth are set in such gum, all as above described and as is well understood in the art.

We now have a temporary denture for tryout in the mouth. As in the case of the full upper denture above described, I have found that this denture fits perfectly every time following care in the preparation of impressions and models.

If it is desired also to add a gold-sheet element corresponding to the scalloped marginal portion of the sheet 28 of Figs. '7 and 8, the procedure described in the remaining portion of this present paragraph is followed. The temporary denture is replaced on the stone model, and artists clay is added thereto, as and for the purposes described under (H) above. Then a stone die is made as described under (1) above. Then an invar or othermetal counterdie is made as described under (J) above. By using this die and counterdie and a blank properly cut from a 34 gauge gold sheet, said sheet is pressed into the required form, as indicated in S in Figs. 19 and 20. Suitable anchor-means, such, for in,- stance as those referred to in the third preceding paragraph are set, as by soldering, to extend from this shell toward the other.

7 Finally, steps (L) and (M) are performed as hereinabove described, to invest the teeth, and to permit the wax gum to be melted out and the final gum of vulcanized rubber or a suitable composition to be substituted therefor; where; upon the denture is completely finished and ready for the patients mouth.

It will be appreciated that the present invention can also be applied, as not herein illustrated but as will readily be understood from the fore going explanations by anyone skilled in the art, to the making of a full gold denture, that is, one wherein all the exposed surfaces are either porcelain (projected tooth portions) or gold surfacing.

Inasmuch as many changes could be made in the above constructions and apparatus and processes, and many apparently widely diiferent embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawin gs shall be interpreted as illustrative only, and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which as a matter of language, might be said to fall therebetween.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A denture including two shaped gold sheets one on the palatal side and the other on the their marginal portions to interlock such portions and thereby brace one sheet against the other.

2. The method of making a denture which when finally completed will incorporate not only a mass of gum material for anchoring the teeth of the denture but also a first metal sheet engagingsaid mass and shaped to fit against a surface within the oral cavity of the patient and a second metal sheet on the opposite side of the denture from the first sheet and shaped to engage said mass and extend over the same to the lines around the lingual sides of the teeth where they protrude from said mass; which method involves shaping said first sheet as aforesaid, then securing thereto a metal reinforcement, then adding to said shaped and reinforced sheet a fusible gum material and setting the teeth in the latter to providea temporary denture, then investing said teeth in a frangible material so that this material thickens the buccalsides of the teeth to shapesaid temporary denture for use as a pattern to be pressed into and then drawn out of a mass of plastic material to leave a molding cavity including a surface corresponding in contour and outline to the second sheet when shaped as aforesaid, then using said temporary denture asa pattern as just described to provide said molding cavity, then casting a suitable material in said cavity to provide a die for shaping the second sheet as aforesaid, then casting a suitable material against said die to make a counterdie, and then squeezing said second sheet between this die and counterdie to shape said second sheet as aforesaid.

3. The method defined in claim 2, wherein after such squeezing of said second sheet, and after removing said frangible materialfrom the denture and placing the denture again on the model, said denture is invested in a mass of frangible material completely enclosing all superficies of the teeth exposed above the model and consequently to imbed the teeth in said mass, and wherein this mass after it has set into a cope is split and the several cope parts are removed with the teeth invested therein, then said fusible gum material is melted away, then said shaped sheets are secured together to form a metal plate the parts of which are held permanently against relative shift, and then with the cope parts placed together as they were before splitting replacing the melted away gum material with a final gum material.

4. The method defined in claim 2, wherein the denture to be made is to be a full upper denture in which a third sheet of metal substantially smaller than the other two metal sheets is to which the third sheet is to be placed in all over contact as above, and these two sheets'are placed in such contact and are secured permanently together while in such contact.

5; Themethod defined in claim 2, wherein said first sheet is to have a marginal portion bentinto a flange atsubs'tantially a right angle to said sheet to stiffen the sheet in the direction of extension of the gum of the patient, and wherein said first sheet, shaped as aforesaid between a die and counterdie, and said die and counterdie are provided byshaping and setting a lesser ridge of settable plastic material on the alveolar ridge of a model of the patients mouth, then casting a die from the model while the latter carries said lesser ridge, and then casting a counterdie from said die, whereby when said sheet is squeezed between said die and counterdie to shape said sheet as aforesaid the die and counterdie wall surfaces resulting from said lesser ridge simultaneously form said flange on said sheet.

6. A full upper denture having a mass of set plastic material extending over the palate ad jacent to the alveolar ridge but mainly extended over such ridge, a first metal sheet shaped to fit tight against the palate, a second shaped metal sheet, said sheets being'also shaped to have their marginal portions flare crosswisely of said ridge to form a housing for said material, said sheets being secured together centrally of their widths and beyond said material back all the way; to the rear of the denture, one of said sheets hav ing a marginal portion bent into a flange at substantially a right angle to said sheet to stifien the same, there being an elongate reinforcing element laid on said last-mentionedsheet and against and following said flange, said element being looped away from the flange at intervals along its length, and said flange being crimped down on said element where the latter lies against said flange between loops.

'7. The denture defined in claim 6, wherein spaced metal struts extend through said mass, said struts including substantially vertical pillars having angularly 'offset feet secured to both sheets to interlock the marginal portions of said sheets on opposite sides of said material.

WALTER An'rzT.

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