US3395454A - Artificial teeth - Google Patents

Description

Au g. 6, p FRUSH ARTIFICIAL TEETH Original Filed June 2 1964 Un te ta es Paten 729 3,395,454 ARTIFICIAL TEETH John P. Frush, Los Augeles, Calif. (704 Highland Drive, Pasadena, Calif. 91103) Continuation of application Ser. No. 378,895, June 29,

1964, which is a continuation-in-part'of application Ser.

No. 322,426, Nov. 8, 1963. This application Sept. 5,

1967, Ser. No. 667,046

' 2 Claims. (Cl. 32-2) ABSTRACT OF THE DICLOSURE An artificial denture includes four artificial teeth mounted on a base. Two of the teeth include a central body shaped like a natural central incisor with the enamel cap on the incisal edge worn away. Each central body along the central portion ofeach incisal edge appears opaque. The mesial and distal edges of each central body have an optical property which simulates the translucency of a natural tooth. The other two teeth are each shaped like lateral incisors with the natural translucent incisal edge present.

This invention relates to improved artificial teeth, and is a continuation of my copending application Ser. No. 378,895 filed June 29, 1964, and now abandoned, which was a continuation-impart of my copending application Ser. No. 322,426 filed Nov. 8, .1963 and now abandoned.

Dentists are constantly striving to provide improved artificial dentures for patients who have lost their natural teeth. In the past, artificial teeth have been objectionable because they do not appear natural, particularly for mature patients.

When a permanent central incisor erupts, i.e., comes in, the mamelon is intact on the incisal edge, and the fresh unmarred qualities of the teeth are essentially sealed in by an unbroken enamel cap. Young and natural teeth, therefore, have a blue incisal (lower) edge and side edges of similar appearance due to the light diffusion through the two layers of translucent enamel which extend beyond the dentine in the central portions of the normal tooth. The main body of a young natural tooth is usually solid and opaque color, with very little or no color texture. At about thirty years of age, the enamel on the incisal edge of each central incisor becomes worn through due to physiologic wear, and the junction between the dentine and the protective enamel covering of the tooth is exposed to fluids in the mouth. As this occurs, the mature natural teeth develop hairlines, or fine cracks, which extend from the incisal edge toward the gingival portion of the tooth. When these hairline cracks are first formed, they are usually chalk white in appearance, and therefore, are lighter in color than the adjacent body of the tooth. Gradually, the older hairline cracks become stained with tobacco tar, food pigments, and the like, and are darker than the later formed hairline cracks, and soon become darker than the adjacent portion of the tooth. The lateral incisor teeth, being shorter, are substantially unchanged and retain their youthful appearance until about age sixty.

Prior to this invention, artificial teeth have failed to take into account the physiologic wearing of the natural central incisors, and thus do not appear natural in a patients mouth.

This invention provides an artificial tooth and a set of teeth which duplicate the appearance of natural mature anterior teeth.

Briefly, the artificial tooth of this invention comprises a body shaped like a natural central incisor with the enamel cap on the incisal edge worn away. A series of 3,395,454 Patented Aug. 6, 1968 generally vertical lines on thelabial surface of the body extend from the incisal edge toward the gingival portion of the body. Means are provided for coloring some of the lines so the artificial tooth simulates a natural mature tooth.

Preferably, the sides of the central incisor are given a blue color to reproduce the natural translucent blue color which occurs in the remnant enamel at the sides of a natural central incisor of a person past 30 years of age.

The preferred form of the invention includes a set of anterior teeth of two mature central incisors flanked by two lateral incisors with the enamel caps on the laterals intact. The enamel caps on the incisal edges of the central incisors are missing to simulate physologic wear, and includes the vertical lines described above to simulate natural mature teeth.

These and other aspects of the invention will be more fully understood from the following detailed description and the accompanying drawing, in which:

FIG. 1 is a sectional elevation of a natural youthful central incisor tooth; and

FIG. 2 is a front elevation of four anterior artificial teeth made in accordance with this invention.

Referring to FIG. 1, a natural tooth 10 includes a central body of dentine 11, which is usually yellowish white and opaque. The dentine is covered by a hard enamel cap 12 which provides an incisal edge 13 where the enamel is of double thickness to form an intact mamelon 14.

As shown by arrows 15, light passing through the enamel overlying the dentine is reflected or absorbed to produce a yellowish white color. Light passing through the two layers of enamel at the incisal edge is transmitted and diffused as shown by arrows 16, so that the incisal edge has a bluish appearance.

Referring to FIG. 2, a pair of central incisor teeth made in accordance with this invention each include a body 18 which preferably is vacuum fired porcelain with coloring matter disposed within it to simulate the appearance of the yellowish-white color of the dentine in a natural tooth. If the artificial central incisors were to represent natural youthful teeth, they would each include a blue incisal translucent edge 22, shown only in phantom line in FIG. 2. However, since the artificial tooth is to simulate a mature natural tooth, the body 20 is formed with the blue incisal edge absent, just as though it had been subjected to the same physiologic wear encountered by a natural tooth. Relatively narrow upright areas 23 adjacent the mesial edges 24 and distal edges 25 of the central incisors are colored blue or made translucent to simulate the translucent bluish color in the same areas of natural teeth due to the remant of enamel.

A plurality of general upright fine hairlines or streaks 26 (shown both in solid and phantom lines) are preferably provided on the labial surface of each central incisor, and extend from the incisal edge generally vertically toward the gingival portion 27 of the central incisors. The hairlines 26 shown in solid line are generally a yellowish brown, and are darker than the rest of the tooth to simulate older hairline cracks which have become stained. The hairlines shown in phantom lines are white or lighter in color than the rest of the tooth to simulate newer hairline cracks which are not yet stained. In this Way, the central incisors exactly duplicate the appearance of natural mature teeth.

The central incisors are mounted in a denture base 28, and are flanked by the usual lateral incisors 29 which include the light-reflecting dentine simulating portions 30, and the usual blue incisal edges 32, which appear in natural youthful teeth, and in older teeth which are not yet exposed to wear by physiologic loss of the incisal edge of the central incisors.

Thus, in accordance with this invention, a group of anterior teeth is provided in which the central incisors simulate physiologic wear and discoloration of natural central incisors, and are mounted with lateral incisors which have the youthful appearing blue incisal edges.

I claim:

1. An artificial denture comprising a denture base, four artificial teeth mounted on the base, two of the artificial teeth each comprising a central body shaped like a natural central incisor with the enamel cap on the incisal edge worn away, means coloring each central body along the central portion of each respective incisal edge to make it appear opaque, means coloring the mesial and distal edges of each central body blue to simulate the translucency of a natural tooth, a series of generally vertical lines on the labial surface of each body extending from the incisal edge toward the gingival portion of the body, means coloring some of the lines so the artificial tooth simulates a natural mature tooth, and the other two artificial teeth each comprising a lateral body shaped like a natural lateral incisor with the blue incisal edge present, the dentine part of each lateral body being opaque like a natural tooth, and means coloring the incisal edge of each lateral body blue to appear translucent like that of a natural tObth'. 7

2. An artifical denture comprising a denture base, four artificial teeth mounted on the base, two of the artificial teeth each comprising a central body shaped like a natural central incisor with the enamel cap on the incisal edge worn away, means imparting to each central body along the central portion of each respective incisal edge to make it appear opaque, means imparting to the mesial and distal edges of each central body an optical property which simulates the translucency of a natural tooth, and the other two artificial teeth each comprising a lateral body shaped like a natural lateral incisor with the natural translucent incisal edge present, the dentine part of each lateral body being opaque like a natural tooth, and means imparting to the incisal edge' of each lateral body a translucencylike that of a natural tooth.

References Cited UNITED STATES PATENTS 1/1941 Myerson 32-8 XR 5/1954 Rydin 32-s XR

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