US2075556A

US2075556A - Artificial teeth

Info

Publication number: US2075556A
Application number: US727209A
Authority: US
Inventors: Merrill G Swenson
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-05-24
Filing date: 1934-05-24
Publication date: 1937-03-30
Anticipated expiration: 1954-03-30

Description

March 30, 1937. w o 2,075,556

, ARTIFICIAL TEETH Filed May 24, 1934 11v VENTOR I j A TTORN Y$ Patented Mar. 30, 1937 UNITED STATES PATENT OFFICE- ARTIFICIAL TEETH Merrill G. Swenson, New York, N. Y.

Application May 24, 1934, Serial No. 727,209

4 Claims.

This invention relates to artificial teeth and has for an object to provide posterior teeth for tact during mating of the upper and lower jaws is reduced, and the tendency to lateral or longitudinal interlocking, setting or wedging effects is practically eliminated.

Another object consists in providing said teeth in which the occlusal surfaces consist substantially of two planes lying at a very obtuse angle to each other, and with the junction of the said planes preferably substantially in line with the longitudinal central axis of the jaw portion in which they are set.

Another object consists in providing said teeth in which the occlusal surfaces of the four teeth in line on either side of either jaw have the plane surfaces just described so arranged that the meet- 5 ing angle of the planes becomes progressively more obtuse from the rearmost molar to the forward bicuspid.

Another object consists in providing such teeth in which the occlusal surfaces are fashioned with depressions or recesses which substantially reduce the contact area and, in effect, present ridges on the occlusal surfaces to aid in the mastication or trituration of food.

Another object consists in providing such teeth in which the occlusal surfaces, particularly of the molars, are formed with grooves or the like constituting escapements or vents from the said depressions or recesses.

A further object consists in providing certain improvements in the form, construction, and arrangement of the teeth whereby the above named and other objects may effectively be attained.

A practical embodiment of the invention is represented in the accompanying drawing in which;

Fig. 1 represents a detail side elevation of the lower and upper posterior teeth on one side of the jaw, in mating or masticating relation.

Fig. 2 represents a section taken in the plane of the line IIII of Fig. 1, looking in the direction 50 of the arrows.

Fig. 3 represents a section taken in the plane of the line IIIIII of Fig. 1, looking in the direction of the arrows.

Fig. 4 represents a longitudinal vertical central 55 section through the parts shown in-Fig. 1.

Fig. 5 represents a plan view of the occlusal surfaces of the upper posterior teeth;

Fig. 6 represents a similar view of the lower posterior teeth; and

Fig. '7 represents an enlarged diagrammatic view showing the contact areas of the upper and lower sets of posterior teeth in one position.

The upper teeth may, for convenience, be marked l, 2, 3, 4, starting with the rearmost molar and the lower teeth be marked 5, 6, I, 8, also starting from the rear.

By reference to the several views, it will be observed that the occlusal or contact surfaces of the teeth, instead of being provided with cusps or individual projections fitted to mate with complementary depressions .inthe surfaces of the opposing teeth, are formed so as substantially to consist of two planes meeting in substantially the center of the tooth at a very obtuse angle, the said line of meeting being depressed below the occlusal surfaces at the inner and outer, or lingual and buccal, sides of the tooth. The said plane surfaces of the lower rear molar 5 are denoted by 9, l0, and the corresponding surfaces of the upper molarl byl I, I2. The form just described is well shown in Fig. 2 of the drawing, and it will be seen that it enables the upper and lower teeth to have a ridge and groove contact which facilitates masticatiomwhile the ridge and groove are so low and shallow as not to permit interlocking or to lead to objectionable lateral stresses.- Indeed, the angles formed by the plane surfaces 9, ill on the-one hand and H, l2 on the other, are so obtuse as to enable the upper and lower teeth to slide upon each other slightly, in both longitudinal and lateral directions, so as to greatly ,promote trituration of food.

The meeting angle of the planes forming the occlusal surfaces of the teeth preferably is slightly more obtuse in the teeth marked 2, 6 than in the teeth marked I, 5; while the said angle in the teeth marked 3, I is slightly more obtuse than in the teeth marked 2, 6; and the angle in the teeth marked 4, 8 is still more obtuse. This brings about a formation such that, when the said four teeth are set in a denture, the combined occlusal surfaces consist of two planes meeting at a depressed angle along the central axis of the jaw member, with the meeting angle becoming gradually more pronounced or acute toward the rear. This formation substantially promotes bi-lateral balance andharmony of jaw articulation and movement while enabling thorough mastication withan elimination or, at least, great reduction of, lateral interference and stresses.

In addition to the slight angular graduation in .the plane surfaces of the sets of four teeth, as hereinabove described, the longitudinal engagement of the upper and lower sets is caused to 5 take place on a slightly curved longitudinal plane by so regulating the slope of the occlusal surfaces and the setting and height of the several teeth as to impart a slightly convex longitudinal surface to the set of four upper teeth, and a corresponding concave longitudinal surface to the set of lower teeth. This is represented in Fig. 4 and is also indicated in Fig. 1.

The occlusal surfaces of the teeth are formed with a number of depressions or recesses which are denoted by the numbers I3, l4, l5, l6, l1, l8, I9, 20, in the upper set of posterior teeth shown in Fig. 5, and by 2|, 22, 23, 24, 25, 26, 21, 28, 29, 30, in the lower set shown in Fig. 6. The exact formation, size, location and arrangement of these several depressions are not matters of prime importance, the intention being to fashion the surfaces into depressions and ridges while still leaving the occlusal surfaces in the form of the angularly disposed planes hereinbefore described. In other words, the depressions and ridges are not formed so as to act in any respect the same as cusp interdigitation, but merely to facilitate mastication or trituration accomplished by the sliding and grinding action of the meeting plane surfaces.

The ridges formed by the depressions or recesses are well shown in Figs. 4, 5 and 6. They may be indicated generally by the numerals ii, 32, 33 and 34 in respect to the upper teeth shown 35 in Fig. 5; and by the

numerals

35, 38, 31 and 33 in the lower teeth shown in Fig. 6.

It will be observed that the ridges on the set of upper teeth, shown in Fig. 5, have a different angular disposition from those on the lower'teeth 40 shown in Fig. 6 so that, when the said sets of teeth are brought into mating engagement, the ridges cross each other to a certain extent and thereby prevent any interlocking while promoting trituration-.. This angular disposition of the ridges and their effective contact areas are diagrammatically shown in Fig. 7 of the drawing in which the ridges on the lower set of posterior teeth are denoted by A; the ridges on the upper set of posteriorteeth by B; and the contact areas.

which. are shaded in the figure, by C.

The ridges, particularly on the molars I, 2, I, 8, are broken away at one or more points, preferably on the lingual and buccal sides, to form escapements or drains for the recesses. These escapements are indicated by 33, 40, 4|, 42, in the molars shown in Fig. 5; and by 43, 44, 45, 46, 41 and 48 in the molars shown in Fig. 6. These escapements assist in the mastication of food by way of facilitating the emptying of the recesses and preventing them from becoming clogged with packed food particles so as to tend to reduce the benefit of the recesses by lessening the grinding and cutting action of the ridges intermediate the recesses.

Reference to the drawing, particularly Figs. 2

and 3, will show that the buccal surfaces of the maxillary or upper teeth, and the lingual surfaces of the mandibular or lower teeth are substantially straight or flat, or very slightly curved, as contrasted with the bulging form of these parts of previous artificial teeth. This formation serves not only to improve the general efficiency of the teeth, but it makes the adjacent edges sharper and thereby specifically enhances to a substantial '75 extent the ease and thoroughness with which they penetrate the food that is being masticated. Likewise, this improvement tends to reduce the size and weight of the teeth.

Certain features of advantage inherent in the subject matter of this invention may be summarized as follows:

The teeth will balance and harmonize with law movement but without cuspinterdigitation. They will balance by means of planes instead of by means of cusps. They will glide over each other as though there were no openings or recesses in the plane surfaces although the rea of the recesses is greater than the remaining area of the occlusal surfaces. In spite of the fact that they work in co-operation as plane surfaces, there is really less porcelain contact than with the cusp form of teeth. 'The recesses or depressions which reduce occlusal contact are out of the contact line of the planes. The slight but gradual rearwardly increasing angle of the plane surfaces serves materially to reduce lateral interference while maintaining balance and harmony of jaw movement. The ridges formed by the recesses or depressions are disposed so as to lie in angular relationship in the upper teeth as compared with the lower teeth, which prevents setting or interlocking of the teeth and also promotes trituration.

the teeth embedded in the gum or jaw material,

marked 49 and 50, is not intended to be significant or accurate in detail; because the shape of this portion of the teeth and the manner of their mounting in the denture constitutes no part of my invention. Any well known or preferred form and manner may be adopted in this connection. It will be understood ,that various changes may be resorted to in the form, construction, arrangement and materials, without departing from the spirit and scope of my invention; and hence I do not intend to be limited to the details herein shown and described, except as they are included in the claims.

What I claim is: 1. In a denture, sets of upper and lower posterior teeth, each set havlngtheir occlusal contact surfaces formed substantially in two planes angularly disposed with respect to each other and meeting at a point intermediate and below the lingual and buccal sides of the occlusal surfaces, the meeting angle of said planes growing gradually more acute from the front tooth of a set to the rear tooth of a set, and said plane surfaces being provided with recesses forming depressions in said surfaces with intermediate ridges, the ridges on each set being arranged in angular relationship to the ridges onthe other set.

2. In a denture, sets of upper and lower posterior teeth, each set having their occlusal contact surfaces formed substantially in two planes angularly disposed with respect to each other and meeting at a point intermediate and below the lingual and buccal sides oftheocclusal surfaces, the meeting angle of said planes "growing gradually more acute from the front tooth of a set to the rear tooth of a set, the occlusal surfaces of one set as a whole being slightly convex in a longitudinal direction and the occlusal surfaces of the other set being slightly concave in a longitudinal direction.

3. In a denture, sets of upper and lower posterior teeth, each set having their occlusal contact surfaces formed substantially in two planes angularly disposed with respect to each other and meeting at a point intermediate and below the lingual and buccal sides of the occlusal surfaces, the meeting angle of said planes growing gradually more acute from the front tooth of a set to the rear tooth of a set, and said plane surfaces being provided with recesses forming depressions in said surfaces with intermediate ridges, the ridges on each set being arranged in angular relationship to the ridges on the other set, the occlusal surfaces of one set as a whole being slightly convex in a longitudinal direction and the occlusal surfaces of the other set being slightly concave in a longitudinal direction.

4. In a denture, sets of upper and lower posterior teeth, each set having their occlusal contact surfaces formed substantially in two planes angularly disposed with respect to each other and meeting at a point intermediate and below the lingual and buccal sides of the occlusal surfaces, the meeting angle of said planes growing gradually more acute from the front tooth of a set to the rear tooth of a set, and said plane surfaces being provided with recesses forming depressions in said surfaces with intermediate ridges, the ridges on each set being arranged in angular relationship to the ridges on the other set, said recesses being freely open at a side to provide for escapment and prevent material from lodging therein, the occlusal surfaces of one set as a whole being slightly convex in a longitudinal direction and the occlusal surfaces of the other set being slightly concave in a longitudinal direction.

MERRILL G. SWENSON.