US2418316A - Dental instrument - Google Patents

Description

April l947- D. REITER 2,418,316

DENTAL INSTRUMENT Filed Jan. 14, 1946 IIAOIIOIAYIIIIIIIIIIIIII Patented Apr. 1, 1947 DENTAL INSTRUMENT David Reiter, Woodside, Long Island, N. Y.

Application January 14, 1946, Serial No. 641,097

2 Claims.

The invention pertains to a dental instrument and more particularly to a sprue holder or grip and guard.

In the art of dentistry it becomes necessary, under certain well known conditions, to take an impression of a cavity previously drilled in a tooth. Such an impression is made in wax which is employed as a component similar to a pattern. This pattern is then employed to make a cavity in a plaster of Paris mold, so that the mold cavity corresponds identically with the cavity of the tooth from which the wax impression took its configuration. The wax pattern is then removed. from the plaster of Paris mold and a precious or semi-precious metal, such as gold is, in a liquefied state, poured into the mold cavity, allowed to solidify and subsequently removed from the mold. The resultant product is an inlay having such a configuration so as to fit snugly and accurately into the tooth cavity. In the process of taking the wax impression hereinabove referred to, it is necessary to initially apply heat to the wax so as to render it easily workable, that is to say, plastic in nature to insure its reaching the innermost limits of the cavity and thus make a true and accurate impression of the cavity. An implement known as a sprue-wire commonly referredto as a sprue is imbedded in the wax to remove the wax impression from the cavity. All of the preliminary steps are most usually conducted by. hand by a dentist who, after removal of the sprue impression arrangement, sets it into a support until such time the dentist wishes to continue with the process of forming th mold and take the subsequent steps above outlined.

With the above, therefore, as a background, it

,is an object of the present invention to provide an improved sprue holder or grip having means.

for positively and firmly holding a sprue.

Another object of the invention is toprovide an improved sprue holder having movably associated therewith, a guard arranged to surround the sprue in spaced relation thereto.

A further object of the invention is to provide, in a sprue holder or grip. a slidably movable support capable of maintaining a sprue in a position elevatedfrom a surface upon which the sprue holder may be placed.

The above and numerous other objects will become apparent from the succeeding description of an exemplified form of the invention illustrated in the accompanying sheetof drawings wherein:

Figure 1 is a plan view of a sprue holder or support embodying the present invention.

Figure 2 is a side elevational view of the sprue, holder illustrated in Figure 1.

Figure 3 is an end elevational view of the sprue grip of Figure l; and

Figure 4 is an enlarged horizontal or longitudinal sectional view taken along the lines 4-4 of Figure 2, looking in the direction indicated by the arrows; a central portion of the sprue holder in this view being not shown.

Referring now in detail to the drawing wherein,

throughout the several views thereof, like reference charactersindicate like, parts, the numeral l is employed to designatetin a somewhat general manner, an improved sprue grip or holder illustrative of the present invention.

The sprue grip generally comprises a barrel or tubular housing or hollow shank 2 formed in part by a predetermined section of tubing 3 having interior threads at or adjacent each end thereof. Rotatably associated with one or a rear extremity 3a of the tube is a plug or closing piece 4 having exterior threads to interlockingly engage the related interior threads'of the tubing and preferably has a portion 5 thereof of substantially the same diameter as the outside diameter of the, tubing to present a somewhat even outer surface at this location. The portion 5 is in abutting relation with the section of tubing so as to, in.

piece T and, like the closing piece, has an outer.

configuration such as to present, from all outward appearances, a forward continuation of the tubing. Extending, longitudinally, centrally or axially through the closing piece is bore a, in axial alignment with a bore 9 in the head so that both bores commnuicate with the interior of the tubing (see Figure 4).

A clamping or gripping means is associated with the housing and, as exemplary of such a means, there is disclosed a rod or link l0 being formed on a forward end thereof with a hook-like member H arranged to surround orengage or hold a sprue l2. The trailing extremity of the rod is provided with exterior threads for a predetermined extent and for the accommodation of a rotatable means or nut l3 having a knurled ex.-.-

terior as at M and arranged to abut the portion 5 of the housing or closing piece. The knurled. surface, of course, is formed on the nut to present asomewhat roughened surface for the successful manipulation of the nut.

From the above description it will be noted that the release action thereof there is incorporated in the mechanism or instrument a releasing feature and for the accomplishment of this purpose, the

rod, at a desired location intermediate its ends, has. a shoulder or abutment l5 secured thereto by any manner Or fashion. This abutment, located within the housing, is spaced a predetermined distance inwardly of the housing from a related iner surface I B of the plug. Extending. around the rod and disposed between the shoulder I5 and surface [6 so as to react longitudinally thereagainst is a resilient means or coil or helical spring l7. The coil spring has a sufficient compressive value to urge the rod toward the sprue engaging extremity of the housing upon a proper 1 manipulation of the nut I3.

It is the present intention or teaching that after a tooth cavity has been prepared for an impression and warmedwax forced'into tooth cavity and carved as desired, a sprue is then placed in a clamped position in the holder or grip.yThis sprue is heated in a flame with a guard I9 pushed back as illustrated diagrammatically in Figure l'soas not to heat the guard. The guard is then pushed back into a position approximating that as shown in full lines in Figure; 1 to guard'the hot'sprue from burning,

a patient. The hot sprue is then imbedded into the wax pattern in the tooth. The sprue is chilled and thus clings to the wax pattern enabling the operator to 'liftthe wax pattern out of the tooth. This process is preferred since thereby there will be no likelihood of'an operator,

finding the-heated sprue hot to the touch, allowing the heated sprue to fall inthe mouth of a patient. After the wax impression is cooled sufliciently to insure its maintaining a true configuration of the cavity from which it was extracted and the heated sprue wire imbedded into thewax, is also chilled, the assemblage is moved in such a manner as to afford its removal from the mouth of a patient. It will be here noted that the housing presents a suitablehandle and sufficient leverage for an easy, positive and accurate removal of the wax impression from the cavity, thus eliminating the necessity of moving the sprue crosswise of the cavity; which latter movement would destroy an otherwise true and accurate impression.

When the wax impression is first removed from a cavity with the sprue imbedded-in it, it is cooled with a spray of cold water to allow it to become solidified thoroughly. The guard then protects thewax pattern from coming in contact. with any object,- such as the hand of a dentist or a supporting surface upon which it might be laid. Great care must be experienced in handling the sprue-impression assembly until such time as the wax has been placed into a standard holder for investment. In order to eliminate any possible defacing of the wax imp'ression, support means has been incorporated in the implement to maintain the sprue and particularly the wax impression 'in an elevated posi- 4 tion. Toward the accomplishment of this purpose, as well as another to be hereinafter set forth, a rest or guard I9 is associated with the barrel and comprises a collar I9a arranged to surround the barrel and slide with respect thereto. The collar may be split or formed as a continuous rin just so long as it presents a snug or sliding fit with the barrel. Extending from the collar in an inclined direction away from the'barrel is a connectingbar or link which vmay be an integral part of the collar or, as illustrated, be formed separately and secured by any manner to the collar. An extremity of band or substantially semi-circular, hoop-like member 2| which extends partially around or through the horizontal extended limits of the barrel as shown most clearly in Figure 3 of the drawing. After an impression has been taken the rest may be rotated about the axisof the barrel thereby placing the impression within the protective limits of the rest and the implement may then be set upon a supportingsurface as indicated diagrammatically in Figure 3 only of the drawing by the reference character 22. It willhere be noted that the impression, indicated diagrammatically as at 23 is supported out of contact with any other object to prevent breakage'or injury to the pattern and the hooplike member presents transversely spaced, curved, sturdy legs 24. If one desires, the sides of the wax pattern is still protected. I v

Another feature is attributed to the rest or guard andthat is, it will function as a' means for holding a patients cheek or tongue out of the way, while-the process of inserting a hot sprue into an impression is being performed, preventing burning of -a patient. It will also be noted that this novel sprue grip is used to place the free end of the sprue wire into-a wax portion of the standard holder. Then the nut I3 is turned to release-the sprue and wax pat- .tern in the holder over which a casting ring is placed and into which-"ring the investment is poured.

From the above it will be noted that various changes and alterations may be made to the illustrated and described construction without departing from within the spirit of the invention and scope of the appended claims. I claim: l 1. In a sprue holder, the combination of, a tubular barrel provided at one end with ahead piece and at another end with a plug, a rod extending through said barrel, head piece and plug, hook-like means formed integrally on' oneend of said rodbeyond said headpiece and-arranged to clamp a sprue to said head piece,- a nut rotatably mounted on said 'rod and in'bearing relation with said plug for drawing said hook-like means toward said headpiece, an abutment formed onsaid rod intermediate the ends'thereof, coil spring means within said barrel and acting a'gainst said abutment for urging said hook-likemeans away from said head piece upon a proper manipulation of said nut, and guard means s'lidably movable on said barrel and having sp'a'ced legs for maintaining said sprue'in elevatedposition; l

2. In a sprue holder, "he combination of, a tubular barrel having at one end a. head piece and at another end a plug, a rod extending through said barrel, head piece and mg'and freely movable relative thereto, :a, bent extremity formed'on one end of-s'aid rod beyondfsaid head guard can rest on a supporting surface and the piece and arranged to clamp a sprue to said head piece, a nut .threadedly mounted on said rod and in bearing relation with said plug for drawing said bent extremity toward said head piece, an abutment formed integrally on said rod intermediate said head piece and plug, a coil spring within said barrel and acting against said abutment and plug for urging said bent extremity away from said head piece upon a proper manipulation of said nut, and guard means slidably mounted on said barrel; said guard means having an arcuate intermediate portion terminating in spaced legs the latter of which are arranged as a support for maintaining said sprue in an elevated position.

DAVID REITER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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