Dental mold posts

June 14, 1966

3,255,992

D. D. KERSTEN

DENTAL MOLD POSTS

Filed April 20, 1965

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INVENTOR.

Damzee D. Kersten

BY

Ed ward D. O'Sr/an Atto/mey

United States Patent Office

3,255,992

Patented June 14, 1966

The mold post illustrated in the accompanying drawing is a presently preferred embodiment or form of this invention. Those skilled in the dental laboratory field will realize that a number of minor modifications may be made in this precise mold post without departing from the essential features of the 'present invention as are set forth in the appended claims.

As an aid to understanding this invention it can be stated in essentially summary form that it concerns dental mold posts, each of which is formed so as to include: a tapered post having a large end and a small end; holding means for securing the post to a castable composition attached to the large end of the post so as to extend therefrom; and at least two legs attached or connected to the small end of the post, so as to be movable with respect to the post, each of said legs extending outwardly from said small end generally along the length of said post.

The actual details of the present invention are best more fully described by referring directly to the accompanying drawings. Here there is shown a dental mold post 10 of the present invention including a post 12 having a large end 14 and a small end 16. This post 12 preferably has the shape of a frustum of a right circular cone having a flat side 13 so as to facilitate its use as hereinafter described. Thus, the post 12 may be considered as having a non-round cross-sectional configuration. At the large end 14 of the post 12 there is located a small cylindrical extension 18 which extends axially with the post. This extension 18 is provided with a plurality of small grooves 20 extending around this axis. If desired another related irregular surface configuration such as a knurled surface can be used in place of the grooves 20.

At the small end 16 in the post 12 a comparatively short, wire like cross bar 22 is connected to the post 12 by an area 23 of the post of reduced cross-sectional configuration. The cross bar 22 extends at right angles to the axis of the post 12. This cross bar carries adjacent to, but spaced a short distance from its ends 24 wire like legs 26 which extend from it generally outwardly from the post 12 and generally in the same direction as the post 12. These legs 26 are connected to the cross bar 22 by comparatively thin flat sections 27 of the legs 26 which, in the preferred embodiment illustrated, are sufficiently thin and flexible or deformable so as to serve essentially as hinges. In the embodiment of the invention shown the legs 26 lie within the same plane as the axis of the post 12. The legs 26 preferably have relatively pointed ends 28 and one or more barbs 30 located adjacent these ends. In order to facilitate handling the barbs 30 are preferably directed so as to extend away from the legs 26 toward the post 12.

This complete post 10 may be easily and conveniently manufactured out of any one of a number of common polymer materials, such as polycarbonate polymers, which, when present in comparatively thin cross sections possess an amount of resiliency or deformability corresponding to the resilient of common thin wires, but which when present in comparatively thick cross sections are relatively flexible. The complete post 10 can also be manufactured out of various known metals such as various types of brasses or the like, as a unitary body. It is also considered possible to separately manufacture the various parts of the post 10 described, and to secure them together by welding or other related techniques, but this is not considered at present to be practical.

When the post 10 is manufactured as shown out of various materials as indicated in the preceding, this post 10 can be utilized in a manner as indicated in FIG. 2 of the drawing. Here there is shown a body of impression material 32 having a cavity 34 located in it. The post 10 can be utilized by engaging -the legs 26 in the area of the ends 24 so as to cause these legs 26 to move

255 992 DENTAL MOLD POSTS

Daniel D. Kersten, Dallas, Tex., assignor to O’Brian and Dicke, Anaheim, Calif., a partnership

Filed Apr. 20, 1965, Ser. No. 449,552 5

Claims. (Cl. 249—205)

This invention relates to new and improved dental mold posts.

., In the manufacture of dentures and other items used ₁₀in connection with the dental field it is conventional to first have an impression taken of an interior of a patient’s mouth using what is referred to as an “impression material.” A number of different impression materials such as alginates and various types of synthetic rubbers are 15 well known. The impression from, a patient’s mouth is then conventionally positioned so that a first liquid composition capable of becoming rigid upon hardening can be cast into it. Before any such composition is cast, however, usually a mold post is located so as to extend into 20 the region where the composition is to be cast so that the composition will engage or otherwise bond with the mold post as it becomes hard.

. The location of such mold posts is regarded as relatively important. Although at least theoretically these 25 posts can be located in the initial composition while it is still in liquid or fluid condition after it is in place within an impression it is normally preferred to locate a mold post prior to such a first composition being cast into the impression. It is common to use pins attached 30 to the impression material and to a mold post through the use of wax or the like in order to hold the mold post in place, in an impression. Various other related expedients serving the same purpose are known. It is normally desired that the position of the mold post with 35 respect to this first composition remain relatively fixed, even if the impression and liquid composition together ‘are vibrated so as to remove air bubbles or the like in the liquid composition.

After what has been referred to as the first liquid com- 40 position has become hard normally a second related composition is cast in the impression material in contact with the first composition and the mold post, and is also allowed to harden. After these two compositions have been created in contact with one another they are removed 45 from the impression material and they are normally separated. In the manufacture of dentures or the like a plurality of such mold posts are used, and the first composition is cut so that each of the mold posts and a part of the first composition can be separately removed from 50 the second composition.

An object of the present invention is to provide new and improved dental mold posts for use in processes of the general category described in the preceding. A more specific object of this invention is to provide dental mold 55 posts which may be easily and conveniently attached to an impression material “mold,” and which when so attached will remain in position during various operations as are indicated in the preceding discussion. A further object of this invention is to provide dental mold posts 60 of the type herein described which may be easily and conveniently manufactured at a comparatively nominal cost.

These and various other objects of this invention as well as many advantages of it will be more fully apparent 65 from a detailed consideration of the remainder of this specification, the appended claims and the accompanying drawing in which:

FIG. 1 is a front elevational view of a dental mold post of this invention; and 70

FIG. 2 is a diagrammatic type view illustrating the use of this mold post.

3,255,992 to any precise angle desired with respect to the post 12. The relative positions of the legs 26 in the cross bar 28 as shown are considered to facilitate this operation. The legs 26 may be inserted within the body 32 by a simple pushing movement so as to position the extension 5 18 in a desired area within the cavity 34.

At this point a first composition 36 capable of becoming hard after a period of time may be cast into the cavity 34 so as to cover and engage the extension 18. Immediately following this casting operation the entire jq body 32 may be vibrated or otherwise treated so as to remove bubbles or the like from the composition 36. The barbs 30 are considered to facilitate the post 10 in place during these steps.

After the composition 36 has become hard the post 15 12 can easily be separated from the cross bar 22 by a simple cutting instrument applied to the area 23. Then the legs 26 and the cross bar 22 can be removed from the impression material 32. At this time the “structure” consisting of the material 32, the post 12 and the com- 20 position 36 may be further processed in accordance with conventional practice.

Because of the nature of the present invention it is to be considered as being limited solely by the appended claims forming a part of this disclosure.