US2112713A - Porcelain-faced dentoid structure - Google Patents

Description

March 29, 1938. M. SEIFMAN 'PORCELAIN FACED DENTOID STRUCTURE Filed May 7, 1956 IN ENTQ' 2% Wk BY ATToR zY Patented Mar. 29, 1938 UNITED STATES PATENT OFFICE 2 Claims.

My present invention relates to porcelain faced dentoid structures and more specifically to a porcelain-faced tooth crown construction and aims to provide certain improvements therein.

Porcelain-faced tooth crowns and other porcelain-faced dentoid structures have been used in the human mouth for many decades. In all such structures with which I am familiar the porcelain facing or veneer is either made up as an article of manufacture in various sizes and colors to simulate natural teeth to be purchased by the dentist and subsequently ground to shape and affixed to the metallic crown or other anchorage, or are specially prepared by dental mechanics to fit each specific crown, bridge or denture, and are shaped, stained and moulded to harmonize with the anatomical form and color of the natural teeth of the patient.

Where the porcelain facings are made as articles of manufacture they must be carefully selected as to size, form and color, then ground and fitted in place on the surface of the metallic crown or other structure to which they are to be secured and then secured to such crown or other structure by soldering, or by a suitable porcelain paste and fused in situ. The composite porcelain-faced metallic crown or other structure is then cemented upon the tooth or in other ways secured in the mouth of the patient. Aside from the fact that it is thus almost impossible to provide from such manufactured -articles, facings which will truly conform'to the anatomical form of the patients natural teeth, the grinding action upon these porcelain facings sets up in them a severe strains which become manifest in due course by a crazing of the facing or veneer, a condition which is highly objectionable.

Where the porcelain facing is specially prepared for a particular crown or the like it is usually soldered to the crown toinsure accuracy of fit thereon, after which the crown must be cemented onto the patients tooth. Where such facings constitute portions of bridge work the bridge must be suitably secured in the mouth of the patient.

In all prior practice where a porcelain crown facing becomes cracked or broken and requires replacement, the crown must be removed from the patients mouth, thus subjecting the patient to unprotected filled teeth for indeterminate periods, to say nothing of the partial destruction of the crown; and where the facings form part of a bridge the patient is subjected to the temporary loss of the use of the teeth thus withdrawn from his or her mouth.

According to my present invention the foregoing objectionable characteristics of prior porcelain-faced dentoid structures is obviated. Furthermore in case of breakage, the facings can be easily and accurately duplicated and replaced 5 upon the crown or the like without the removal thereof from the mouth of the patient. Moreover the construction is such that the facing will more easily and accurately fit the crown or other anchorage and provide for the complete covering of the buccal or labial face of the crownso as to obscure the metallic backing thereof. Also as each veneer is individually prepared it can be so made that the least amount of tooth grinding will be necessary for the dentist and he can preserve the vitality of the patients own tooth and yet obtain the esthetic effect he desires. These advantageous features and others not specifically enumerated I accomplish by providing the veneer with baked-in pins which cooperate with sockets formed in the veneer-engaging surface of the crown or the like and through the medium of which pin and socket connection the veneer can be cemented and accurately held in definite seating relation on the crown. 25

The invention will be better understood from the detailed description which follows, when considered in conjunction with the accompanying drawing, wherein:

Figure 1 is a fractional front elevation of several incisors or front teeth, one of which is crowned to receive a porcelain facing.

' Fig. 2 is a front elevation of a porcelain facing intended to fit over the crown in Fig. 1.

Fig. 3 is a sectional view of a tooth with a metallic crown having a porcelain facing thereon embodying my invention.

Fig. 4 is a section taken substantially along the plane of the line 44 of Fig. 3.

Fig. 5 is a front elevation of the tooth shown in Fig. 3 with the porcelain facing removed therefrom.

Fig. 6 is a side elevation of a porcelain facing such as shown applied to the crown of Fig 3.

Referring to the drawing and particularly Figs, 3 to 6 thereof, let A indicate a tooth herein shown as a molar, B the alveolar process or jaw bone and C the gum tissue which projects above the alveolar border. It is assumed that the tooth A is partially decayed and has been filled as indicated at D and that the tooth is fitted with a metallic crown E which is usually of gold. To obscure or hide the metal of the buccal face of the crown it is covered with a porcelain facing or veneer F which is made to conform to the anatomical contour of the adjacent teeth.

According to the present invention the porcelain facing or veneer F is made of a form and secured to the crown in a manner such as will require the dentist to do a minimum amount of tooth grinding; This is rendered possible by the fact that the veneer F is separately prepared for eachindividual crown from high fusing porcelain and has embedded and baked therein a platinum orequivalent U-shaped metal pin G, the ends of which extend or project from the inner or crownengaging face of the veneeradjacent the mesial and distal edges thereof to provide anchoring pins 9. These anchoring pins g are positioned to cooperate with recesses or sockets H in the buccal face of the crown and said sockets preferably extend into the mesial and distal walls J and K respectively of the crown to assure a deflnite seating for the veneer. The veneer may be cemented onto the crownprior to or after the crown has been cemented onto the tooth.

The advantages of having the pins baked into the veneer and of, cementing the veneer onto the crown are that in case of breakage of the veneer it may be very easily replaced with a new veneer by the dentist merely taking a facial impression in compound of the crown with pins in position within the sockets therein and with the aid of said impression a new facing may be moulded and baked and thereupon cemented onto the crown without removing the same from the mouth of the patient.

The technique to be followed by the dentist in carrying out the present invention is substantially as follows He will first remove sufficient tooth structure from the occlusal and labial surfaces to provide a sufficient-thickness of porcelain for'strength andshading." A tube impression in compound or inlay waxis-then obtained of the tooth and a plaster impression of the adjacent teeth. A wax bite impression and a sample of theproper shade of the patients tooth is also obtained.- These are usually sent to a dental laboratory whereat the crown and porcelain facing or veneer are. prepared.

From the impression in compound an amalgam die is made and the die is then set into the plaster impression and a model is poured. When this model is separated it is then articulated with the wax bite to get the occlusion of the opposing teeth. The amalgam die is then removed and .a platinum matrix band is swedged in place. The pin is then placed where it is most suitable for strength of the porcelain facing to be baked, after which the porcelain is added and carved as the esthetics of the case and shade-desired require. The platinum matrix with the pin and porcelain are then placed in the furnace and heated to proper temperature. When the facing is complete it is then placed back on the amalgam die and the crown part carrying the labial, lingual, mesial, distal and occlusal faces are waxedto the facing, the facing is then removed and the waxing of the crown is invested and then cast in whatever metal one may desire to use. After the casting is made it is then finished and polished to fit the baked facing and is ready for use for either an individual restoration or as an abutment for bridgework for partial denture restoration.

In Figs. 1 and 2 I have shown the invention as applied to a front tooth or incisor which has a crown L fitted thereover, said crown having recesses or sockets M extending into the mesial and distal walls thereof. The facing or veneer N has a platinum pin 0 embedded therein with the ends of the pin projecting from the inner face of the facing in position for cooperative engagement with the recesses M. To secure the veneer N upon the crown L it is merely necessary to apply suitable cement to the buccal face of the crown L and apply the veneer N thereonto with the ends of the pins 0 engaging in the sockets or recesses M.

From the foregoing detailed description it will be appreciated that I have disclosed a simple, practicable and novel dentoid" porcelain facing or veneer which will possess the various advantageous characteristics set forth in the opening statement, and although I have shown and described but two embodiments of my invention as applied to a molar and incisor, it is to be understood that the invention is not limited to the specific constructions since they may be varied within the range of the dental mechanics skill,

without departing from the spirit of the invention as claimed.

What I claim is:

1. A dentoid structure comprising a metallic jacket tooth crown having a buccalface with shoulder portions adjacent the mesial and distal edges thereof, a previously prepared porcelain veneer having an inner surface of complemental form to the buccal'face and shoulder portions of the crown, said veneer having metallic pins projecting from its inner surface adjacent the mesial and distal edges thereof, the buccal surfaces of the shoulder portions of the crown-havin'g recesses therein extending into the mesial and distal walls of the crown at points complemental to the pins projecting from the veneer for receiving said pins, and said Veneer being cemented to the crown with the pins seating in the recesses.

2. A dentoid structure comprising a metallic jacket'tooth crown having a convex buccal face with shoulder portions adjacent the mesial and distal edges thereof, a previously prepared porcelain veneer having an inner concave surface of complemental form to the buccal face of the crown and having a U-shaped metallic pin ernrecesses.

MORRIS SEIFMAN.

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