US1312141A

US1312141A - Tooth

Info

Publication number: US1312141A
Authority: US
Publication date: 1919-08-05
Anticipated expiration: 1936-08-05

Description

W. F. SLACK.

ARTIFICIAL TOOTH.

APPLICATION FILED FEB. 24. I919.

' 1,312,141. Patented Aug. 5,1919.

4 6 a:z:mmmxmmmmm\mummw I Al%rny a the toothis composed and that of theanchor.

WILLIE r. SLACK, orivmnonnsrnn, NEW niuvrrsi-nnn,

ARTIFICIAL ro m.

' ...s ecifieation ortettersratent. f Patented Aug. 5, 1919.1

' Application iiled alar e4, 1919; SeriaINo. 275,671;

To all whom Mandi concern."

Be it known that LVILLIEFI SLACK, a

citizen of the United States, and a resident of Manchester c State of New Hampshhe, have invented an Improvement in Artificial Teeth, of which.

the following description, in connection with the accompanying draw ngs,1s a spec1fication, like characters on the drawings repre senting like parts.

The invent on to be hereinafter described rlelatesto an lmprovement in artificial teeth and more particularly tothemeans for at taching such teeth to a plate,such as rubber,

celluloid, or othersuitable character.

lHeretofore it has been the common practice to form artificial teeth ofa suitable composition such, for instance, as porcelain, and to provide an anchorage betweenthe teeth and the plate to which the teeth are to be secured, such anchorage usually comprising a platinum pin. When the, artificialjteeth have been heretofore subjected to the firingj operation, the platinum pin or anchor has been embedded in the porcelain tooth and as the tooth cooled after the firing operation,

the coefficient of contraction or,converse ly, of expansion between the substance of whlch has been such as to cause or platinum pin, This is due to the the porcelain to crack.

fact that as the porcelain contracts about the embedded platinum pin, its contraction, is; g impeded by the less contractibility of the,

pin itself as the parts cool. Under these circumstances something must give way and this has been usually the material or porcelain of which the tooth iscomposed. The crack usually extends transversely of the lingual or labial surface, although this is not always the case. The crack thus formed or the line of weakness thus produced, is

usually not visible to the naked eye, but it; an extent that after the teeth exists to such have been secured to the plate and are subjected to the usual strains incident totheir use, the teeth are found to give way or break along the line of weakness produced by the differential contraction of the material of the tooth and that of the pin or anchor.

One of the objects. of the present inven tion is to provide an artificial tooth with an anchor which will not interfere with the uniform contraction of the material of the tooth as the tooth is cooled after the firing process, and will permit such relative conounty of Hillsborough, and

. traction between thematerial of the tooth and the plnor anchor,as to obviate the for mation of a line ofweakness or crack in the tooth. j

Another feature of the present invention cons sts in: providing an artificial tooth with an anchor or pin of such character that it will effectively hold the tooth to the plate into which the anchor projects. In carrying the invention into practical effect, the anchor or pin is usually and preferably formed ofa metalrod of suitable size provided on its exterior surface with barbs or projections which may be produced most readily in the form of screw threads When such form of anchor is embedded in the porcelain of the tooth when theflatter is shrunk or contracted during cooling,ma nifestly the pin becomes secured permanently and uniformly throughout the embedded portion thereof in the material of the tooth.

In order to permit the differential expan sion ofthe material of the tooth or porcelain and that of the anchor or pin, the pin; is

provided with a slot in the end thereof which projects into the material of the tooth,

uch slot permitting movement of the two or more parts of the pin toward or from eaclrother due to the contraction and expanslon of thematerial of the tooth. f I have found excellent resultsto follow from providing the pin with a single slot extending from the embedded end portion of the pin toward the inner portion ofthe tooth, but, obviously, the pin may be provided with more than a single slot and in some cases such duplication or multiplication of slots may be desirable.

In thedrawing; X l c t Figure 1 isa section view .onan enlarged scale show ng an artificial tooth securedto,

the backing. or plate in accordance with the present invention; s

Fig.2 is a perspective view showing in general outline the artificial tooth with the anchors or pins embedded therein;

Fig. 3 is a view of a slightly modified form of anchor or pin and its relation to the artificial tooth;

Fig. 4 is an enlarged view representing one of the pins in Fig. 4, the enlargement being multlplied many times in order to make clear the characteristic features thereof.

In the drawings, the artificial tooth 1 may be formed of any suitable substance such,

for instance, as porcelain, and theplate 2 to which the artificial tooth is to be secured, may be likewise formed of any suitable ma terial, such as rubber, celluloid, or the like.

In order to secure the tooth to the plate, an anchor or pin 3 is provided with a roughcried" exterior surface, preferably formed as screw threads 4, although, as will be evident,

the roughened characteristic of the outer surface of the anchor. or pin 3 may be other wise produced. It ispreferable to form the anchor or pin with the roughened or threaded' surface throughout its length for thereacient of expansion and contraction of the substance of the tooth and the substance of the pin or anchor differ, and heretofore the 7 result has been that a crack either visible 7 or invisible has usually extended across or transverse to the lingual surface of the tooth which eventually permits the tooth to collapse or break duringuse. To effectually overcome this defective condition of the artificial tooth when secured to its anchor or pin, lhave found that by slotting the pin, preferably throughout the portion embedded in the tooth, the substance of the latter, in cooling, "may contract by more or less closing the slot of the anchor or pin and thereby prevent the formation of visible or invisible cracks. i

In the present instance of the invention, the anchor or pin is provided with a slot 5 preferably extending from the end6 of the pin toa point 7 longitudinally of the anchor or pin and approximately or. preferably throughout the portion of the pin embedded inthema'terial of the artificial tooth, as indicated in Fig. 1. 7 j When the anchor or pin 3, slotted as described, is placed in the material of the tooth while they latter isin plastic or'semi-plastie condition, the slot 5, much magnifiedin the copies of this patent may be obtained for five cents each, by

permit contraction of the drawings, receives little or none of the plastic material of the tooth, the consequence being that when the material of the tooth is cooled after firing, the slot 5 furnishes a sufficient yield between the pin and the material of the tooth during contraction to permit full contraction of the latter without rupture or the formation of visible or invisible cracks.

While the single slot 5 has been indicated in the pin 3 it will, of course, be understood that several such slots may be provided at angular relation to each other and extend longitudinally of the anchor or pin.

In some casesa single anchor or pin 3 will be quite sufiicient, in view of the roughened exterior surface thereof, to hold an artificial tooth to its backing or plate, but in some instances two or even more may be employed, as indicated in Fig. 2.

The anchor or pin may take various forms, as indicated in Fig. 3 where the anchor or pin 8 is formed substantially U-shape, its end portions 9 being embedded in the substance of the artificial tooth 1 and each of said end portions being provided with the longitudinal slot and roughened exterior surface, substantially as described hereinbefore.

Claims:

1; An artificial tooth provided with an anchor or keeper comprising a pin having one end embedded in the material of the tooth and provided with a slot extending longitudinally of the anchor or keeper to tooth as it is cooled.

2. An artificial tooth having an anchor or pin embedded therein and provided with a longitudinal recess extending throughout the portion of the pin embedded in the artificial tooth to permit uniform contraction of the tooth in cooling, and having a roughened or tooth surface extending transversely to the general longitudinal dimension of the anchor or pin and about the longitudinally recessedor slotted portion.

In testimony whereof, I have signed my name to this specification.

WILLIE F. snac addressing the Commissioner 01' Patents,

Washington, I). 0.