PROSTHESIS HANDLING SYSTEM

Abstract: A prosthesis handling system and method. A handle (10) is formed with a dental prosthesis so that the handle can be used for supporting and handling the prosthesis through to final finishing, when the handle is cut off. The handle preferably has both a ring (22, 38) for supporting the structure on a post (64, 48) and a ball (24, 40) for grasping the resulting structure.

Description: PROSTHESIS HANDLING SYSTEM BACKGROUND OF THE INVENTION This invention is directed to a handling system, and particularly a system for handling the metallic ' portion of a dental prosthesis from the molding of the metal portion, through to intermediate and finishing work • on the metal structure, until the cutting off of the handle as the last step. Dental prostheses are often .partially or completely cast of metal in an investment casting lost wax molding process. These prostheses must be handled through the intermediate and finishing processes subsequent to the molding. In some cases, a metallic substructure is cast of metal, and subsequent thereto a ceramic is selectively placed thereon. When suitably positioned and configured, the ceramic is baked on the substructure. In order for the ceramic to properly adhere to the .substructure, the metallic substructure must be absolutely clean. Handling such a substructure with the fingers places skin oils thereon, which prevents proper ceramic adhesion. The handling of such a substructure even with gloves can cause contamination of the surface and subsequent poor adhesion. The ideal clean surface is the untouched surface as it comes from the investment casting mold. Cleanliness and convenience in handling are also necessary or helpful in the handling of other dental prosthetic devices. In the past, there has been no handling system by which such can be accomplished. SUMMARY OF THE INVENTION Briefly, and in general terms, the invention provides a prosthesis handling system comprising an investment cast metal dental prosthesis structure and a metal handle attached to the cast metal dental prosthesis structure for handling and supporting the cast metal dental prosthesis structure. The handle has an engagement device thereon for engagement by a support for supporting the metal dental prosthesis structure. In another aspect, the invention provides a prosthesis handling system comprising a wax master handle for attachment to a wax master prosthesis for investment. The handle has an engagement device thereon for engagement by a support for supporting the prosthesis. The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view' of several different prostheses either in wax form or i cast form showing the handle attached to the dental prostheses and also showing the handle alone, for use in the prostheses handling system of this invention. FIGURE 2 shows a special clamp hand tool used for engagino a portion of the handle, for use in handling the investment cast metal prosthesis structure. FIGURE 3 is an enlarged view, with parts broken away and parts taken in section, showing the engagement of the hand tool on a portion of the handle. FIGURE 4 shows a group of the handles in wax form, whereby one or more of the handles can be removed from the group and attached to the wax master prosthesis for use in molding. FIGURE 5 shows a firing tray with a plurality of posts thereon for- the support of prostheses in one step of the prosthesis handling system of this invention. FIGURE 6 is'an enlarged view of one of the support pins shown in FIGURE 5. ' FIGURE 7 is an enlarged view of an alternate ' support pin which can be used in conjunction with a firing tray or another tray. ' IGURE 8 is a perspective view of an instrument for manipulating the handle when it is in wax form. FIGURE 9 is an enlarged view, with parts broken away, showing the instrument of FIGURE 8 manipulating a wax handle and holding it for attachment to another wax structure, DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGURE 1, dental prostheses 12, 14 and 16 have attached thereto a handle 10 which is an essential portion of the prosthesis handling system of this invention. In the manufacture of the prosthesis, a wax master is provided, and the wax master is employed to provide a cavity in- the molding material in the investment casting lost wax molding process. After the molding material is hardened, the wax is melted out and metal is poured therein. This metal may be a substructure which will receive a ceramic coating over a portion thereof, or may be a metal structure such as a crown. During the processing of the metal structure or substructure cast in the investment mold, the handle 10 . -5- is employed' to support the metal structure during the intermediate processing from the investment casting step to the final finishing step where the handle is removed. FIGURE 4 shows a plurality of the handles 10, each identical to the other, on a common bar 18. The -entire structure in FIGURE 4 is of wax. Each handle has a neck 20, ring 22 and sphere 24. Stick 25 , see FIGURES 8 and 9, has a resilient nose piece 26 which is formed with resilient jaw opening 28. The jaw opening is engaged over the ball 22 of one of the wax handles 10 and. the stick is used to bring the wax handle 10 adjacent a wax master prosthesis 30', see FIGURE 9. The wax handle 10 is attached to the prosthesis by the application of limited heat so that it is adjoined as generally indicated in FIGURE 1. For a long prosthesis with a substantial metal structure or substructure spanning several tooth widths, -two or more' handles 10 can be attache As is seen in FIGURE- 9, the jaw opening 28 of the soft nose piece 26 grasps ball 24. Even. though ball 24 is a wax structure at this point, the jaw opening 28 can hold and control handle 10 to hold it in position for attachment as shown in FIGURE 9. The wax master of the prosthesis, including handle 10, is completed, attached to appropriate sprue and gates, and is placed in a mold for investment casting. The molding compound is poured around the wax master ' and, after the molding compound is hardened, the wax master is melted out. Next, metal is poured into the mold cavity to form a metal structure of a prosthesis or a metal substructure • of a ceramo-metal prosthesis. The prosthesis handling system of this invention is particularly useful in the handling of the metal substructure which is to become a part of a ceramo-metal prosthesis. The surface of the substructure must be clean for the ceramic to bond to the investment cast metallic substructure. This precludes handling of the metallic substructure, even handling by gloves. If conventional tools are used in handling such a substructure, the serrated jaws of the conventional tools can cause damage to critical surfaces. However, in accordance with this invention, the investment cast metal structure carries thereon the handle 10 in metallic form. It has been investment cast into metal, along with the rest of the metal structure. ' FIGURES 2 and 3 illustrate prosthesis 32, which is. an investment cast metallic prosthesis or prosthesis substructure and compares with the wax master prosthesis 30 shown in FIGURE 9. The metal prosthesis substructure 32 carries thereon metal handle 34, which is the same as handle 10. ' Metal handle 34 has a neck 36, ring 38 and ball 40. As is seen in FIGURE 3, the ball 40 is substantially spherical- and is grasped within the cavities 42 and 44 respectively in jaws 46 and 48 in instrument 50. Instrument 50 is similar in structure to the conventional surgical clamp, but instead of having serrated jaws, has the cavities 42 and 44 adjacent the tip thereof. The cavities 42 and 44 are preferably shaped so that they are part of the surface of the sphere of the same diameter as ball 40. Thus, the ball 40 can be clamped therein. When clamped in that manner, the instrument 50 can be used as a manual support for the handle 34 and the metal prosthesis structure 32 which is cast with the handle. Thus, the metal prosthesis can be engaged, supported, positioned and moved through the manual control of instrument 50 without touching any of the surfaces on the metal structure 32 which will require work prior to finishing. Thus, the other surfaces of the metal prosthesis are unmarked and uncontaminated by touching. It is. particularly important to note that the jaws of instrument 50 do not extend past the ring 38. In this way, the entire opening in the ring is available ' when the substructure is being handled by instrument 50 so that the ring may be placed over support pins of the type shown in FIGURES 5, 6 and 7. In this way, a prosthesis can be handled without manual or instrument engagement on the prosthesis metal structure or substructure from the moment it is divested from the mold to the final removal of the handle. Particularly in the case of a metal substructure of a ceramo-metal prosthesis, the- substructure must be supported during the placement thereon of the ceramic ' material and must be supported during firing of the ceramic material- FIGURE 5 shows firing tray 52, preferably of ceramic structure and capable of withstanding firing heat. Firing tray ' 52 has a plurality of openings 54 therein with th β openings extending generally upright with respect to the plane of the firing tray. Supporting pins 56 and 58, • respectively shown in FIGURES 6 and 7, can be inserted into selected openings 54 to carry thereon the substructure for firing. Pin 56 has a body 60 which carries a stop 62 i- the form of a circular ring. The lower part of the body inserts into the opening 54 and stop 62 engages against the top surface of tray 52. Tapered pin 64 ends in shoulder 66 which is the top of body 60. The entire structure is of a suitable material to withstand firing temperatures. Tapered pin 64 and shoulder 66 are dimensioned so that ring 38 can be received thereover, with the ring engaging against shoulder 66. In this way, the metal substructure, carrying its ceramic coat, can be positioned upon the tray, as shown in FIGURE 5. The entire tray carrying several of such substructures is placed in the furnace for firing of the ceramic. To aid in spacing of the various substructures on tray 52, the support pin 58 is provided. Support pin 58 is the same as support pin 56 except that tapered pin 68 and shoulder 70 are offset from the lower part of the body 72 so that the support pin can be offset from the opening ' s 54 in the firing tray. In this way, infinite adjustment between adjacent tapered pins 68 is possible. This is particularly useful when there are two handles 34 on a metallic substructure which is to be fired. After firing, the ceramic is hard and, if no further ceramic work is contemplated, the ceramo-metallic prosthesis can be handled by gloves. As part of the final finishing of the prosthesis, the handle 34 is cut off and the place where the neck 38 was attached is polished. This invention has been described in its presently contemplated best mode, and it is clear that it is susceptible to numerous modifications, modes arid embodiments within the ability of those skilled in the art and without the exercise of the inventive faculty. Accordingly, the scope of this invention is defined by the scope of the following claims.

Claims: WHAT IS CLAIMED IS: 1. A prosthesis handling system comprising: an investment cast metal dental prosthesis structure; metal handle means attached to said cast metal dental prosthesis structure for handling and supporting said cast metal dental prosthesis structure, said handle having engagement means thereon for engagement by a support for supporting the metal dental prosthesis structure. 2. A prosthesis handling system comprising: a wax master handle for attachment to a wax master prosthesis for investment, said handle having engagement means thereon for engagement by a support for supporting the prosthesis. 3. The prosthesis handling system of Claims 1 or 2 wherein said engagement means is a ball of substantially spherical configuration on said handle. 4. The prosthesis handling system of Claim 3 further including a manually operable instrument associated with said ball for engaging on said ball for supporting and positioning said prosthesis. 5. The prosthesis handling system of Claim 4 wherein said instrument has a resilient nose piece having a jaw opening therein for engagement on said ball. 6. The prosthesis handling system of Claim 3 wherein there is a ring on said support means in addition to said ball. 7. The prosthesis handling system of Claim 6 wherein said ring is attached adjacent said prosthesis and said ball is attached to said ring. 8. The prosthesis handling system of Claim 7 wherein said ball is positioned sufficiently away from said ring so that a manually operable instrument having jaws with cavities therein can engage on said ball for handling said prosthesis without covering the opening in said ring. 9. The prosthesis handling system of Claim 7 wherein said ball is mounted on said ring and said ring is mounted on a neck which connects to the prosthesis. 10. The prosthesis handling system of Claims 1 or 2 wherein said engagement means is a ring on said handle and having an opening therethrough for positioning over a support pin. 11. A firing tray having a plurality of openings in the top thereof, a plurality of pins, each of said pins having a body having a lower end sized to fit into said openings in said tray so that said pins are supported by said tray and are forwardly directed with respect to said tray, said pins having an upward facing shoulder thereon, said pins and said firing tray being made of material which withstands ceramic firing temperature; a dental prosthesis having a handle thereon, said handle having a ring therein, said ring being engaged over one of said pins in said tray so that said dental prosthesis is supported for firing. 12. The firing tray of Claim 11 wherein said handle also has a ball thereon adjacent said ring so that said ball can be engaged by a manual instrument for placement and removal of said dental prosthesis from said firing tray without contact with said dental prosthesis. 13. The method of handling a dental prosthesis comprising the steps of: attaching a wax handle to a wax master of a dental prosthesis; investing the wax handle and wax master dental prosthesis in an investment compound; pouring metal into the cavity produced by the wax handle and wax master dental prosthesis to form a metallic dental prosthesis with a handle integrally molded thereon; divesting the metal dental prosthesis with its metal handle; and acting upon the dental prosthesis while holding the dental prosthesis by means of its handle. 14. The method of Claim 13 wherein the holding step comprises holding the handle by means of an instrument which grasps a convex portion on the handle. 15. The method of Claim 13 wherein the dental prosthesis is held by mounting the handle on a post which extends through an opening in the handle. 16. The method of Claim 15 wherein the handle is moved with its opening with respect to the pin by the step of engaging a convex portion of the handle away from the opening by means of an instrument so that the instrument can move the dental prosthesis to and away from support on the pin without touching the dental prosthesis.

Inventors: BERGER ROBERT P, BERGER, ROBERT, P.
Applicants: BERGER ROBERT P, BERGER, ROBERT, P.
Application year: 1985
Main classification: A61C3
IPC codes: A61C3, A61C13, A61C19