US1813583A - Method for the production of dentures - Google Patents

Description

july?, 1931. W. s'. RICE n,s13,5s3

METHOD FOR THE PRODUCTION 0FV DENTURES Filed May 28, 1928 E u QW?? ///4.

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/M/ENTOR' l Patented '.uly 7, 193i PATENT oFFI'cE -WILLIAJJILVS. "RICE, F WASHNGTON, DISTRICT OF COLUMBIA.v

METHOD Fon THE PRODUCTION or nnNTtrnns Application inea May 28,1928. serial No. 281,278.

(GRANTED UNDER THE AcToE MARCH a, 1883,`As AMENDED APRIL so, 192s; 37o o. e. 757) This invention described herein may -be manufactured and used by orfor the Government for governmental purposes, without the vested and the denture, which replaces it, vul-` canized or otherwise treated and thus by the elimination of expansion and warping, pro- !zo ducing a den-ture which will conform to the contour of the gums and hard palate to the minutest details.

v Another object of this invention is to provide means. for embedding the teeth in metal in the investment flask thus holding themsolidly in position for packing and vulcanization, curing or otherwise hardening the base plate material.

Other objects of this invention are to materially 'lessen both time and labor in the production of `dentures and otherl restorative forms by effecting a reduction in the amount 4of grinding and polishing necessary for fini.shing and to provide metallic separating layers between the upper and lower sections of the flask. With these and other objects in viewthis invention consists in certain novel details of construction, combination and arrangement of' parts to be more set forth and claimed. f

Brieflystated, this invention consists in an improved method for producing models, dentures, inlays, etc., lby the use of metallically surfaced models or metallically lined molds between the hard smooth surfaces of which the plastic mbdel is invested and the plastic denture vulcanized or cured to form the 1inished denture or other artificial restoration.

Referring' more particularly to the accomparticularly hereinafter` panying drawings in which corresponding parts are indicated by similar reference L 'characters F igl. 1 is a sectionized isometric'view of an impression tray with wax or plaster impression contained therein.

Fig. 2 is a sectionized isometric view of an impression tray and impression material contained therein, the impressionV cavity being coated with a metallic lining.

Fig. 3 is a partially sectionized elevation of an upper and lower full denture mounted on an articulator. v

Fig. 4 is a partially sectionized perspective View of upper model shown in Fig. 3, mounted in the lower section of (an investment flask.

Fig.' 5 is a partially sectionized perspective -view showing the upper mold coated with metal and mounted in the investment flask.

Fig. 6 -is a sectionized elevation showing the upper model invested in a closed flask for vulcanizing, curing, molding or casting. y

The customaryl method of making vulcanite dentures involves the paramount features toy wit: taking the impression, pouring the plasnter casts, mounting casts on the articulator, `building the wax models, investing, packing L. i

and then vulcanizing.

In the usual meth od the plaster cast is made by pouring plaster-directly into the limpression'. This givesa plaster model, or cast of the patients gums on which the wax model denture is built. This model denture is nvested entirely in plaster, immersed in warm Water and afterthe evacuation of the Wax, rubber is packed in the plaster mold and vuli canized.

The porosity of the plaster causes adhesion of the vulcanite and the'compressibility of the ,plaster and uneven expansion thereofl .causes expansionand warping of the denture.

The result is rough vulcanite dentures which do not' follow the exact contour of the patients gums and hard palate, and which require considerable grinding and polishing to, approximate a fit and to make the exterior of the denture resemble in smoothness the gums.

yIt is therefore the aim and purpose of this invent-ionto provide a method to eliminateI the deleterious results caused by investing the It will be noted that for the sake of brevity and clearness the materials which are used most commonly in prosthetic dentistry are( referred to throughout the following description, namely, wax for the construction of the base plate of the model, plaster for the molds, and rubber for vulcanization in the production of the finished denture or other restorative part. However, it is to be understood that in the application of my process it is not necessary to adhere to these materials as any suitable substitutes may replace them with not only equal, but in some cases, superior results.

For example, bakelite may be used instead of rubber, cement instead of plaster, etc. IVhcn bakelite is used for dentures, plaster cannot be used for molds in the ordinary dental processes, since it would be detrimental to the finished product to permit contact of surfaces of bakelite against those of plaster. In my improved process plaster molds may be used for bakelite dentures as there is an intervening layer of metal between the plaster and the bakelite.

In 'the illustrated embodiment characterizing this invention, the numeral (1) Fig. l represents an impression tray and (2) the impression material, either wax, composition or plaster. The valley or groove (3) represents the impression made therein by the gums of an edentulous patient.

In Fig. 2 is shown the impression tray,

impression material and impression as shown in Fig. l, but it will be noted that covering lthe entire surface uf the impression is a metallic coating or. layer (4) This metallic layer \(4) has been sprayed onto the surface by a metallic air brush similarv to those used in blowing minute particles of metal on the hulls of vessels until a. protective coating of sufficient thickness is deposited.

The metal as it is blown on adheres to either the hull or to the surface already laid down and the thickness of the metallic layer is determined by the period of the operation and the character of spray. Preparatory to spraying the impression surface a suitable separator may be applied, then after a metallic layer of suflicient thickness has been deposited, said impression surface with its metal coating is covered with plaster and the latter built up to provide the requisite base (5). I/Vhen the plaster has hardened to the desired extent and become aiixed to the metallic coating, the impression material (2) is removed and the metallically coated cast is now ready for mounting on the articulator.

A complementary cast for the lower jaw having a plaster base (5') and as above outlined, a metallic coating (4') is built, and with the aid of a bite plate (not shown) both are mounted in their proper relative positions on an articulator (6) as clearly shown in Fig. 3 of the drawings.

Upon these upper and lower metallically covered casts are developed the wax dentures (7) and (7 by the ordinary process of first laying a base plate then building up the ridge and finally placing the teeth (18) in position. At the completion of the attachment of the teeth and after the usual adjustments for occlusion and articulation have been made the models are removed from the articulator and placed in the fiask.

In the asking operation, the models embodying the cast with its metallic coating, plaster base (5) and wax denture (7) are placed in the lower section (8) of investment as defined the entire surface (11) of the plas` ter and of the wax model denture (7) including the teeth (18) may be covered with a thin application of a separator and coated with a metallic layer The upper section 14) of the investment flask (9) is placed on top of the lower section (8) as shown in Fig. 5, and filled with plaster, after which the flask is closed and immersed in warm water. On completion of investment and elimination of the wax the sections are separated, the molds may be coated with a separator and packed with dental rubber, whereupon the flask is again closed and placed in the vulcanizer.

After vulcanization, the denture is removed from the flask, ground and polished in the usual manner, but since the vulcanization of the rubber has taken place between hard smooth metallic surfaces, grinding and polishing is necessary only to remove the ridges which mightpbe formed at the line union of the flask surfaces, or small sections of metal adhering to the surface of the denture. A

For making partial plates the same procedure is followed as in the case of full plates. For single plates, or single partial plates and bridge work the occluding model may be metallically coated. This provides a more solid occluding surface for manipulation on the articulator.

For inlay work an impression of the preparedcavi-ty and either a portion of the tooth which is immediately adjacent the cavity, or the whole tooth isObtained. This impression is then coated or lled with metal, as previ- -ously described, until thecoating is of sufii-4 cient thickness to be removed from the impression or mold without breaking.

If desired the cast which is made inthis Way may be backed with a plaster base as When making plate casts. This cast is an eX- act model of the tooth or that portion of the tooth containing the cavity. With a model of this sort the dentist has an exact metallic representation of the patients tooth to Work'on in the laboratory, ,which manifestly facilitates handling in the subsequent laboratory operations. f

In inlay work the wax model o`f the .cavity may be coated entirely with metal except for `thesmall opening for the pin' which provides for a sprue hole. -The metallic cast thus formed may be invested.

. In making castings for inlay Work, metallic base plates, bridge Work, etc., the plastic model may be entirelyv coated with metal except Where it is necessaryv for feed and vent sprues. The metal used for this purpose Will necessarily be one having a high melting point. A cast thusformed may then be filled with molten metal in the usual manner, that is, by either centrifugal vforce or by creation of a vacuum' at the vent sprues.

Dies and counter-dies for sWaging metallic base plates may be constructed by spraying an appropriate metal l on the impression and model and either building up the dies or counter-dies'by continuing the spraying procon the metallically lined molds. Which are'I used, and the ease With Which they are built.

ess or by mounting the surfaces on metallic or'other suitable bases.

In conclusion it will be noted that the superiority of my improved4 method is dependent Tin, which `at present seems to be-the most desirable metal, is extremely inexpensive, and any lslight eXtra cost lwhich might be in- -curred in the use of this m'ethod is however amply offset by the reduction bethtime and labor" incidental to rinding and polishing for `finishing the den ure.

` Although in the foregoingcertain elements have been described as best adapted to perform the functions allotted? them, nevertheless it is to`be understood that various ini-nor changes mayT be resorted to within the scope ,of the appended claims Without departing from or -sacrificing any of the princlples of f I-Iaving described my invention, what I claim as new and Wish to secure by Letters Patent is: l 1. "Aprocess for producing artificial restorations of the oral cavity, consistingin producing a metal surfaced cast, developing a model upon said cast, metallizing the exterior surface of the model, embeddingcthe modeland castinacementitioussubstance,evacuatingthe modelling material to provide a cavity Whose .internaldimensions conform to the dimensional requirements of the desired restoration and perfecting the latter within said cavity.

2. A process for producing artificial restorations of the oral cavity, consisting in promensions conform to the dimensional re" quirements of the desired restoration and then perfecting said restoration Within the cavity.

3. A process for producing artificial restorations of the oralcavity, consisting in forming a model With metallized exterior and interior surfaces, embedding the metal in a cementitious substance, evacuating the modelling material to define arnet-al Walled cavity in the cementitious substance, the internal dimensions of Which'conform to the dimensional requirements ofthe desired restoration and completing said restoration Within said cavity. 4. A process for producing artificial restorations of the oral cavity, consisting in forming a model with metallized exterior and interior surfaces, embedding the model in a cementitious substance, evacuating the modelling material to define a metal Walled cav- ,ity the diinensions of -Which conform to the dimensional requirements of the finished restoration, filling said cavity with a restoration producing material and subjectin the latter to the temperature requisite to t e finished product. t

5. A process for producing artificial restorations of the oral cavity, consisting in forming a Wax model denture with metallized exterior andinterior surfaces, embedding the model denture in' a cementitioiis substance, evacuating the Wax modelling material .to produce a metal Walled cavity having the dimensiona equirements of the finished restoration' and filling the cavity With a restoration producing material and then subjecting the latter `to temperatures 4requisite to the finish-ed product.

6. A process for producing artificial res- .torationsof the oral cavity, 'consisting in metal spraying'an impression surface, forming la model cast therefrom, developing a model upon the: cast,l metal spraying the model surface upon the exterior surface, embedding the model and cast in a cementitious substance, effecting evacuation of the model- .ling material to produce a metal Walled cavity, the dimensionsof Which correspond `to those of the finished restoration and perfecting said restoration Within said cavit p i 7. A process for producing-artificlal trestorations ofthe oral cavity, consisting inr "15 metallic shell conforming to the lingual side Wax model denture upon the cast, metal desired artificial denture, filling the said spraying the exterior surface of the model matrix With suitable denture material, and denture, embedding said denture in a cehardening the material to form the finished mentitious substance, effecting evacuation denture.

5 of the Wax modelling material to produce a WILLIAM S. RICE. 70

metal Walled cavity, the dimensions of which correspond to those of the finished restoration and then completing Vsaid restoration Within the cavity. c

8. A process for producing artificial resto- 'v rations of the oral cavity, consisting in metal spraying an impression surface previously formed in molding material, treating'said metallized surface with a plastic substance,

removing the molding material to provide a 90 metal cast, developing a Wax model denture upon the cast, spraying a metal surface upon the exterior of the model denture, effecting evacuation of the Wax of the denture to produce a metal Walled cavity, the dimensions 85 of which correspond to those of the finished restoration and perfecting said restoration Within said cavity.

9. A process for producing artificial restorations of the oral cavity, consisting in V 0 forming an impression surface in modelling material, imparting a metal surface to the first mentioned surface, transferring the metal surface to a cementitious substance, re-

moving the molding material to provide a 95 metal cast, developing a Wax model denture upon the cast, metallizing the exterior of the denture, embedding the denture in a cementitious substance, effecting evacuation of the Wax material of the model denture to provide 100 a metal Wall cavity the dimensions of which correspond to those of the finished restoration forming material and subjecting such material to temperatures requisite to obtaining the finished restoration.

10. The method of producing an artificial denture involving the production of a metal Wall Which method comprises forming a trial denture with teeth in place, forming a rigid 110 of the trial denture and teeth, forming a mold including the shell as a Wall thereof,

v removing the trial denture leaving the teeth and shell in place, filling the mold with suitable denture material, and hardening the material to form the finished denture.

11. The method of producing an artificial denture involving the production of a metal mold which method comprises making a rigid 100 metallic shell conforming exactly t0 the surk face of the mouth, forming a trial denture With teeth in place, forming a rigid metallic shell conforming to the lingual side of the 4 trial denture and incasing said teeth, remov- 125 ing the trial denture leaving the teeth rigidly held by the latter shell, placing the two shells together in matrix forming relation to pro-A videa cavity 'Whose internal dimensions conf il form to the dimensional requirements of the

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