US1808102A - Dental casting post - Google Patents

Description

June 2, 1931.' D. E. vANs DENTAL CASTING POST Fileifmay 7, 1929 Patented June 2, 1931 UNITED STATES HPixrnlxli" oFFic/Ez DAVID E. EvANs, or coLUMBUs, 01110, Assreivon 'ro THE connMBUsnEN'rAL MAN'U- i rAo'runINe COMPANY, or ooLUMBUs, onro, A coRPoRA'rIoN DEN'L'AL CASTING rosr Application filed May 7, 1929. SeraIN'o. 361,022.

I am aware that casting posts have been used heretofore in dentistry, in association With artificial teeth and especially interchangeable artificial teeth. Their purpose and function are well understood by those skilled in the art.

The casting post usually is composed of a precious metal alloy. The post is so shaped and formed that only a portion engages, or

` coacts, with an artificial tooth. The remaining portion of the casting post proj ects above the artificial tooth so that Wax may be formed about the post to make a base, or |hacking member. The Wax and castingpost are next K5 removed silpnultaneouslyi fro-m the tooth.

. Then through the well-known dental casting technic vthe Wax is replaced with metal, the latter usually composed o-f a stable precious metal alloy.

Casting posts have been madeand sold by dental manufacturers to dentists, to be used in the way set forth and for the purpose of aiding in artificially restoring lost natural teeth. This method of restorationusually applies to what is oommonly called bridge- Work. i

What has been recited is understood and practiced generally in the art.

One object of my invention is to so construct the casting post that it has inherent retentve, or holding power when the Wax is formed about it. In the past many ofthe casting posts have separated from the wax during the construction of a dental bridge and have thus caused loss of both labor and time. This is p-a-rticularly a disadvantage to the dentist.

Another object of my invention is to so construct the casting post that it has inher- 49 ent retentve, or holding power, when the metal is cast against it. In the past it was not uncommon for the post to separate from the cast metal, the former sometimes pulling away bodily. This frequently occurred after the bridge was in service in the patients mouth. In such cases the cast gold did not attach itself strongly to the post during the process of casting. .In fact the degree of strength between the two, in repeated trials, 59 is seldom constant and poor unions are apt to occur at any time. Such fa'ilures are serious mishaps, both to the patient and dentist. Either, or both parties suffer much inconvenience and loss of time.

Another object of my invention i-s to so construct the casting post that it will beunnecessary to use hi'h fusing casting metal, Dr over heat lower fusing casting metal in an efiort to procure a rigid union between the post and casting metal. -In the past it has been common to over heat 'the lower fusing casting metals in an effort Vto getl greater strength of union with the post by sweating or alloying. This procedure has a'tendenicy to burn outsome of the lower fusing metals in the casting alloy, which may cause the alloy to 'changemateriallyi in its physical properties. Such physical property changes sometimes leads to failure during'the casting process, or may effect the tensile strengthof o a finished piece' of work. Further, the overheating. of the casting alloy often seems to' have -a deleterious effect upon the metal of the lcasting post. Breakage of the. post itself, is not an uncommon failure in -such in- 'stances The exact'cause of the breakage of the post itself is not known to me, yet it has been construed that mixing different alloys of different characteristics may upset the 'physical propertiesof both metals. In this 'instance the casting post'is an alloy possessing different 4characteristics than the casting alloy. Further, it has been construed that the 'post breaks under these conditions because i the arrangement of the molecules of the metal have been disturbed and cry-stalization has taken place. Regardless of the exact cause, breakageof the post does occur at times when this process of high heat casting is employed. i What Vhas been said above applies in spirit whenV a 'casting alloy of high fusing range is ,employed vin association with a post whose fusing range is more 'or less lower.

When my casting post is employed it is unnecessary to over heat the casting alloy or use a higher fusing casting alloy. Through the inherent retentve construction of my post, the casting alloy is retained in a mechanical way in addition to any `surface sweating union that may take place during the casting process.

Another object of my invention is to so construct the casting post that it satisfies the requirements for practical production in manufacture. i

i In the drawingsr' J i,

Figure 1 is a side elevation of a casting post embodying my invention.

post.

Figure 3 is an end elevation of the same,

The reference numeral 1 designates' the post, 2 the web which is ofless diameter than the post, and 3 the retaining member, all

formed integrally, preferably vby casting.

The retaining member, preferably, is 'wedge shape 1n one dnnenslon as shown in Figura 1,

the side edges 4 and 5 converging toward the web 2. In the edge 9 of the retaining member 3 I provide an arcuate recess or depression and form a swelled protruded, or bulbouslike extension 10, 11 on each side wall of the retention member 3 the top of which is in the plane ofthe bottom and side walls of the recess 8, said extensions 10, 11, functioning as additional anchorage for the hacking metal cast on the post. LetV it be understood that by the termpost I mean the article as a whole.

In the manufacture of my casting post, I

may choose to construct it so that the post 1 may have one' or a plur'ality of'notches 1a as shown in Figure 1. The function oflthese notchesis to serve as a mechanical retention for the post, When the latter is assembled with the artificial tooth, the two being de- 'tachably united by cement, or Vany other suitable material. i

It will readily be understood that the metal for the hacking cast to my casting post finds 'a very firm anchorage in the wedge forma;

tion of the retention member andin the bulb ous formations 10 and 11.

What I claim is: p 1. vAs a new article of manufacture,`v a casting post for the hacking for an artificial :tooth, comprising a post, a Web, and a reten tion member having a recess in its rear edge and protuberances. from two side. Walls thereof, all formed integrally.

V2. As a new article of manufacture, a casting post, for the backing ,for an artificial too'th, comprising a post, a web, and' a retention member, having a recess in its rear edge and protuberances on two side walls thereof along the bottom and side walls of the recess. In testimony whereof I `aflix my signature.

' DAVID E. S.

Figure 2 is a rear elevation of. my casting

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