US1149239A - Crown-tooth and pin therefor. - Google Patents

Description

J. L. WILLIAMS.

CROWN TOOTH AND PIN THEREFOR.

APPLICATION FILED MAR. 6. 1915.

Lm fiwm PatentedAug. 10,1915.

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JAMES LEON WILLIAMS, OF PELHAM, NEW YORK, ASSIGNOR TO THE IDENTIS'IS SUPPLY COMPANY, A CORPORATION OF NEW YORK.

CROWN-TOOTH AND PIN THEREFOR.

intense.

Specification of Letters Patent.

Patented Aug. in, 19 15;.

Application filed March 6, 1915. Serial No. 12,485.

Therefor, of which the following is specification.

This invention relates to crowns for teethand more particularly to the pin for holding the tooth crown to the root of the tooth, and my object is more especially to provide a construction in which the tooth crown shall be so supported and attached to the root that a greater strength of union is secured than in the customary practice heretofore en'iployed, and moreover to provide a con struction of pin which shall give great stability against displacement of the tooth, which displacement has heretofore been possible by the bending of the p n. D

My object is also to provide a pin in which the prong entering the root and the prong secured in the crown tooth is offset sutliciently to enable the latter prong to extend down in the direction of the biting or incisor edge of the tooth in the case of front teeth, so that a greater length of pin may be employed and be surrounded with a more substantial portion of the porcelain.

My object is also to so shape the pm at the juncture of the tooth prong and the root prong that it shall provide a rearwardly eX- I tending heel for receiving the upward thrust of the lingual portionof the tooth to prevent rotation of the tooth relatively to the root by the bending of the pin, and moreover to provide a pin structure which will effectually prevent the possible rotation of the tooth upon the pin about a vertical axis, the construction being such that the pin cannot possibly turn in the porcelain tooth structure.

lVith the above and other objects in View, the nature of which will be more fully understood from the description hereinafter, the invention consists in the novel construction of the pin and its combination in association with the tooth as hereinafter more fully described anddefined in the claims.

Referring to the drawings Figure l, is a vertical section througlia tooth-root and a I tooth crown secured by a pin einlioilyiiig my invention; Fig. 2 is a front elevation of the same; Fig. 3 is a plan view of the tooth crown showing the recess for the pin; Fig. L is a vertical section through the tooth crown on. i i of Fig. 3 and line of Fig. 1, with the pin removed; Fig. 5 is a perspective view of my improved pin; Fig.

6 is an enlarged top view of the'sanie; and Fig. 7 is a perspective view\of the tooth crown.

Heretofore in practice it has\been customary to provide the tooth crown with a pin having an extending prong fon insertion into the root of the tooth, in which the prongwas in alinement with the pin portion within the tooth structure. Furthermore; it is customary to bake the pin in the crown so that the pin is a unitary structure with the tooth crown. Where the pin is in this manner rigidly connected with the porcelain crown it is often necessary to bend the prongs to insure proper positioning of the crown in the mouth. This weakens the construction both by possible injury to the pin and to the angularity given thereto. Furthermore, in teeth as heretofore made eniploying straight pins, the location of the pin in the porcelain crown, to adapt it to the root, has caused the pin to be located objectionably far to the lingual. side of the tooth; and to secure the proper strength, it has been necessary to increase the porcelain at thisplace and thus deviate from the natuand pin 1 am enabled to overcome the above recited objections inherent in the former practice, and in accomplishing this I provide a pin structure in which the tooth prong and the root prong are definitely offset and the metal at the juncture of these prongs is widened, more particularly in the direction of the offset to provide a heel at the rear of the prongs to engage the crown to ward the lingual side, and thereby more strongly brace the crown against displacenient under hard usage, prevent any possible capacity of the porcelain crown to rotate upon the pin, and to provide full engagement between the pin and the crown without abnormal or excess iorcelain at the rear or lingual side. ll'lorcover. the metal in the pin is so thickened at the junction between the crown and the root that there is no possibility of its bending under undue stress.

Furthermore; the construction of my improved pin and crown is such that the pin .may be employed separate from the crown,

and after .being cemented into the root the crown may be cemented to the pin and inposition upon the root and adjusted to the proper. position without any necessity of bending the pin. 7

More'specifically referring to the drawings, 7 represents the root prong of the pin, which is substantially coaxial with a quasitriangular reinforcement or enlargement 8.

Projecting downwardly from the base of the. enlargement 8 is a crown prong 9, the axis. of which prong is substantially parallel to the axis of the root prong 7, and said prong 9 is located at the forward part of the base of the. substantially triangular enlargement 8, andtherefore the prongs 7 and .9;are in efi'ect'oflset with respect to each other. The I base of the enlargement 8 is also provided,

withga short downward projection 10 located at the rear part of the base and opposite to where the crown prong 9 is located. Therefore, the saidprojection 10 and prong 9 are opposite each other and .in substantially parallel planes and the said projection '10 may be said to extend from the heel of the enlargement or reinforcement 8 andwhich heel and projection actas a brace for the tooth crown against backward thrust;

The tooth crown 11, which is to be fitted with the pin, is provided with a suitable deep bore 12 adapted to receive the prong' 9, and with asubstantially trapezoidal or other suitable shallow recess 13 into which cemented in place and prevents any disfits the lower or base part of the reinforcement portion 8; This recess 13 of the crown, at the'bottom and adjacent the side opposite the deep bore 12,'is. provided with a'pocket 14 adapted to receivethe heel projection 10 of the pin. Itwill be seen from Fig. 1- that by offsetting the prong 9 from the prong 7 the bore 12 for the prong 9 in the crown 11, is formed near to the front or labial part thereof, therefore leaving more-material for the rear of the crown into" which theheel may be stepped. This is of great importance, as the maximum stress applied tothe crown is always from the rear, toward the front, and therefore the crown is greatly strengthened when the bore 9 is made nearer 'to the front than to'the rear, or contrary to what has heretofore been the general practice. By engaging theheel projection 10 at the rear of the crown pin with the pocket 14 in the crown, I further brace the crown at the rear. The reinforcement or body 8 .having its base fitting into the shallow recess 13 while its prong 9 fits down into the bore 12 and its heel projection into the pocket 14, makes a strong 'connectionwhen placement by torsional action.

Attention is called to the fact that inthe preferred form of my improvedpin the heel portion at the junction of the crown and root prongs is substantially dovetail in shape, as can be easily seen, more particularly in Figs. 2, 5 and 6. The heel reinforcement, which projects into the pocket. 11 of the cavity 15' of the crown locks the pinto the crown when the cement is made to bind the crown with the root, as best seen in Fig. 1. That'is to say, the cement 19 filling the cavity 15 and pocket 14 seals the crown pin to the crown and supplements the cementing'of the prong 9 in the bore 12 thereof. The partly engaged base of the reinforcement 8, and also the heel projection'10, prevent the turning of the crown pin in the crown.. The prongs 7 and 9, either or both, I

.may be indented or serrated asat 18, if deslredto more strongly holdin the cement within the bore 12 of the crown and bore 16' g I of the tooth root 17.

The pin may be made of any suitable metal or metal alloy or of a'plated or coated metal if so desired, as I do not restrict myself .in this regard. These pins may be cast,. forged, or stamped from sheetmetal; the ,latter with a forging action to shape the parts is preferable,'both because it pro-- duces a cheaper and stronger pin than by other methods of manufacture.

From the foregoing description, taken in connection with the accompanying drawings,

the advantage of the construction of my improved pin and crown, separately and combined, will be readily understood by'those skilled in the art to which the. invention pertains; and it will be appreciated that the advantage of this improvement is that it effects a more widely distributed and better balanced hold of'the pin on the porcelain crown, and gives afar stronger and substantially triangular reinforcement portion coaxialwith the rootprongiand having its lower end extending both to the front and to the rear of the root prong, said ,reinforcern'ent portion having at the rear of its base a short heel projection, and

more secure attachmentlto the natural root 7 at the forward end of its base a crown 2 prong having its axis substantially parallel to the axis ofrthe root prong but out of axial alinement therewith.

heel projection arranged rearwardly from the junction of the said crown and root prongs, allpf the pin except the heel projection being of substantially uniform thickness and the heel projection being of 5 greater thickness at its lower part.

4. A tooth crown having its end which comes next to the root provided with a deep bore and a rear pocket of greater width and greatly less depth than the bore and 20 connected therewith by a shallow recess.

In testimony of which invention, I hereunto set my hand.

v JAMES LEON WILLIAMS.

v Witnesses:

' J. R. SHEPPARD,

L ROY FRANTZ.

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