US2141487A - Artificial denture - Google Patents

Description

Dec. 27, 1938. M. A. PLEASURE ARTIFICIAL DENTUHE Filed Oct. 30, 1935 V///rv INVENTOR M ATTORNEYJ' Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE ARTIFICIAL DENTURE Max A. Pleasure, Elmliurst', Flushing, N. *2.

Application October 30, 1935, Serial No. 47,341

Claims.

My invention relates to artificial dentures and, more particularly, the invention has reference to novel posterior teeth forming a part of fullupper and lower dentures.

' In general, my invention has reference to novel occlusal surface arrangements for the posterior teeth of upper and lower dentures whereby the stability of the lower denture on its base is maintained in an eflicient and satisfactory manner.

Further objects, advantages, and characteristics of my invention will become apparent from the following detailed description.

My invention resides in the coacting artificial dentures, arrangements and features of the character hereinafter described and claimed. I

For an understanding of my invention and for an illustration of one of the forms thereof, reference is to be had to the accompanying drawing, in which:

Figure 1 is a view of the upper denture as it appears when looking upwardly at the bottom thereof;

Fig. 2 is a perspective view of the lower denture;

Fig. 3 is a vertical sectional view, partly in elevation, this view being taken transversely through the first molars of the upper and lower dentures;

Fig. 4 is a vertical sectional view, partly in elevation, this view being taken transversely through the second molars of the upper and lower denture; and v Fig. 5 is a perspective view showing the first and second molars on one side of the lower denture.

As shown on the drawing, U represents an upper denture and L a lower denture, the upper denture U comprising a suitable base I which supports the incisor teeth 2, the canine teeth 3, 3, and the upper posterior teeth comprising the first premolars 4, 4, the second premolars 5, 5, the first molars 6, G, and the second molars I, 1. Similarly, the lower denture comprises a suitable base la. which supports the incisor teeth 20., the canine teeth 3a, 3a, and the lower posterior teeth comprising the first premolars 4a, 4a, the. second premolars 5a, 5a, the first molars 6a, 6a, and the second molars la, la. The aforesaid incisor and canine teeth may be conventional and, therefore, no specific description will be included herein concerning them.

Conventional posterior teeth of the artificial type usually have their occlusal surfaces substantially at right angles to their respective longitudinal or vertical axes, and these teeth are designed to be set either upon a horizontal bite plane or on the surface of a theoreticalsphere which has its center in the region of the forehead. In accordance with the present invention, my novel posterior teeth have their respective 6 occlusal surfaces set at an angle to their vertical axes, respectively, whereby the occlusal surface of each set of teeth comprising two premolars and a first molar (all adjacent) is pitched at an angle with respect to a horizontal plane. 10

More specifically,'as shown in Figs. 1 and 3. the upper first molar 6 shown at the left has a high lingual margin 0. and a-low buccal margin b. It results, therefore, that the occlusal surface 0 of said last named upper first molar 6 is inclined or.pitched downwardly in a direction extending from right to left, Fig. 3. Similarly, as indicated in Fig. 1, the occlusal surfaces 0 of the first and second- premolars 4 and 5 shown at the left are inclined in the same general direction as the occlusal surface 0 of the above named first molar 6. Accordingly, it follows that the occlusal surfaces of the teeth 4, 5 and 6 shown at the left ,of Fig. 1 are disposed in substantially a single plane and that this plane is inclined approximately as indicated by the occlusal surface 0 of Fig. 3.

In a manner generally the same as described above, the teeth 4, 5 and 6 shown at the right of Fig. 1 have their occlusal surfaces included in substantially a single plane and this plane is pitched downwardly in a direction extending from left to right, Fig. 3, as. exemplified by the occlusal surface 0 of the first molar 6 at the right of said Fig. 3.

In accordance with the invention, the occlusal surfaces of the sets of lower teeth, corresponding with those discussed immediately above, are disposed substantially fiush or in substantially parallel relation with respect'to the occlusal surfacesof the respective sets of upper teeth. This arrangement is exemplified in Figs. 2 and 3 wherein the lower first molar 6a. shown at the left has a high lingual margin al and a low buccal margin bl. It results, therefore, that the occlusal surface cl of said last named lower first molar 6a is inclined or pitched downwardly in a direction extending from right to left, Fig. 3. Similarly, as clearly appears from a consideration of Fig. 2, the occlusal surfaces cl of the lower first and second premolars 4a. and 50. at the leftare shown as inclined in the same general direction as the occlusal surface of the above named lower first molar 6a. Accordingly, it follows that the u occlusal surfaces of the teeth'la, 6a, and is shown at the left of Fig.2 are disposed in substantially a single plane, and that this plane is inclined substantially as indicated by the occlusal surface cl shown at the left of Fig. 3. It follows.

therefore. that the planes of the respective sets of occlusal surfaces 0, cl at the left of Fig. 3

extending from left to right, Fig. 3, as exemplified by the occlusal surface cl of the first molar 60. shown at the right of said Fig. 3. Therefore, as shown, the planes of the respective sets of occlusal surfaces c, cl at the right .of Fig. 3 maintain the same parallel, flush relation as described above in connection with thesets of occlusal surfaces at the left of said Fig. 3.

In accordance with an important feature of the invention, the occlusal surface of each of the hereinbefore described second molars is pitched or inclined in a reverse direction as regards the adjacent set of first molar occlusal surfaces c or cl as the case may be. Thus, as shown in Figs. 2 and 4, the second molar I at the left has a low lingual margin a2 and a high buccal margin 112. It results, therefore, that the occlusal surface c2 of said last named second molar I is inclined or pitched downwardly in a, direction extending from left to right, Fig. 4, and this occlusal surface 02, then, defines a plane which may be inclined, in accordance with the present preferred practice, approximately as indicated in Figs. 4 and 5. In a. manner generally the same as just described, the second molar 1 shown at the right of Fig. 4 has its occlusal surface 02 defined by a plane which, in a corresponding manner, is

pitched downwardly in a direction extending from right to left, Fig. 4.

In correspondence with the foregoing, the oc-' clusal surface of the second molar 1a shown at the left of Fig. 4 is disposed substantially flush or in substantially parallel relation as regards the adjacent, upper second molar occlusal surface 02. This arrangment is illustrated in Fig. 4

wherein the second molar la shown at the left has a low lingual margin a3 and a high buccal margin b3 whereby it results that the occlusal surface c3 of said last named second molar la is inclined or pitched downwardly in a direction extending from left to right, Fig. 4. In substantially the same manner as just described, the second molar la shown at the right of Fig. 4 has its occlusal surface 03 defined by a plane which is disposed substantially flush or substantially parallel with respect to the adjacent, upper second molar surface 02.

In accordance with present preferred practice, it is desirable, for purposes of proper food mastication, that the posterior teeth of my invention be provided" occlusally with non-interlocking grooves or channels and, further, it is desirable that such grooves or channels of the upper denture teeth be disposed transversely or in a desired crossing relation with respect to the grooves or channels of the lower denture teeth. However, the invention is not to be thus limited.

This phase of the invention is clearly illustrated in Fig. 2 wherein the occlusal surfaces of the posterior teeth (premolars and molars) are shown as formed with the generally transverse grooves 8 which form transverse ridges and peripheral cutting edges as illustrated. For the purpose of more closely simulating the appearance of natural teeth, the aforesaid grooves 8 may be notched as indicated at 9 if desired.

With an arrangement of the character just described, the occlusal surfaces of the upper denture posterior teeth. (premolars and molars) may be provided with the grooves l0. As shown, these grooves "I are disposed generally in end-to-end relation and, -as clearly appears, they are arranged so as to be crosswise with respect to the grooves 8 of the lower denture teeth.

It shall be distinctly understood that my invention is not to be limited to a grooved arrangement such as shown in Fig. 1.- Thus, if desired, the grooves Ill of the upper denture teeth may be so arranged that the end-to-end relation of Fig. 1 is departed from although, to a desired degree, the crosswise relation of the two sets of grooves should be adhered to. Therefore, in lieu of the grooved arrangements described above.

it shall be understood that other suitable patterns and arrangements of grooves for the occlusal surfaces of both upper and lower denture teeth may be used as desired.

As appears from a consideration of Fig. 5, the longitudinal axes of my novel posterior teeth are disposed, normally, in substantially a vertical direction. This is advantageous because the teeth are thereby caused to take a natural position with consequent decrease in the formation of unnatural food pockets, little or no change in the ,area to be occupied by the tongue, etc.

- The inclination of the various planes defining the occlusal surfaces of the sets of teeth as hereinbefore described may vary within rather wide limits. At present, it is believed that these planes should be tilted with respect to a true horizontal plane by an angle of about 15 degrees, more or, less.

However, it will be understood that my invention is not to be thus limited since, for example, the aforesaid angle may be varied between approximately 5 degrees to 25 degrees, more or less, as desired.

While the pitch of the occlusal surfaces of the second molars differs to a marked extent in di rection from the pitch of the premolars and first molar, it should be noted that the change of pitch is gradual and not sudden, the transition occurring in the posterior portion of the first molar and the anterior portion of the second molar, i. e., in the regions adjacent to the contact between the first and second molars.

The teeth of my invention, normally, are set so that the upper teeth are more prominent buccally than the lower teeth to thereby prevent cheek-biting; however, this arrangement may be reversed where required, as in so-called crossbite cases, without impairing the advantages inherent in my construction.

The advantages of a denture arrangement as constructed in accordance with my invention are numerous and of importance since, by the invention, the dentures are stabilized on their respective bases and so arranged as to increase the comfort and efiiciency of mastication. The configuration imparted occlusally to the artificial teeth of my invention is based on the conception that the temporomandibular joint (that between the lower jaw and the skull) is distinguished for the great variety and freedom of movement which -restrict movements, as has been maintained.

it permits, and not for its capacity to guide or For this reason the teeth of my invention are constructed to allow correspondingly free and varied movements of the lower jaw relative to the upper jaw when the dentures are in position.

'O'cclusal prominences which intercept the path of jaw movements normally used in chewing are rigidly avoided. While the occlusal modelling is primarily directed toward mechanical efficiency, an effort has been made to depart as inconspicuously as possible from teeth, especially as regards the teeth of the lower denture.

The two premolars and the first molar constitute the area of most effective chewing. The pitch of the occlusal surfaces causes the biting pressure to generate resultants at right angles to the occlusal surfaces, 1. e., downward and inward toward the tongue. These resultant forces are of great effect in maintaining the stability of the lower denture upon its base. This phase of the invention is well illustrated in Fig. 3 which contains a graphical representation of the vertical closing pressure and the stabilizing resultant forces. These,as shown,are directed lingually and theypass inward of the gum ridge upon which the denture saddle rests. These resultant forces, then, are between the two gum ridges. Necessarily, therefore, they tend to and do seat the lower denture upon its base.

The reverse pitch of the sets of second molars 1, 1a, 1, 1a, which is posterior to the main chewing area, is intended to provide for contact and mutual support of the upper and lower dentures on the so-called balancing side-the side not actually engaged in chewing. Thus, when the lower jaw moves laterally while applying pressure upwardly, the posterior teeth (upperand lower) on one side have the morsel of food therebetween. The upper and lower posterior teeth (excepting the upper and lower second molars) at the other side separate during this lateral excursion of the lower jaw. However, engagement is maintained between the inclined occlusal surfaces of the upper and lower second molars last named to thereby prevent tipping of the lower denture. In this manner, unseating of the lower denture is prevented during lateral excursion of the lower jaw. This, obviously, is a marked advantage of my invention.

The upper and lower teeth of my construction are not required to stand in such precise relationship to each other that the introduction of a morsel of food immediately upsets the calculated relations required for chewing efiiciency. My teeth maintain chewing efficiency in any relation which the jaws may assume during normal mastication and, at the same time, help to stabilize the dentures by the pitch of the occlusal surfaces of the premolars and the first molar together with the altered pitch in the second molar area. The cross-bite arrangement, where required, does not disturb stability or efliciency.

The present forms of artificial teeth are efiective mainly by virtue of the crushing. force applied to them by movement of the lower jaw vertically. They oppose each other through the morsel of food, which is thereby compressed and more or less crushed and pierced. The teeth of my invention reduce opposition between the upper and lower teeth and increase efiiciency and sharpness by permitting a lateral component to enter into the chewing movement. This gives the occlusal ridges of the lower teeth a linear slidthe character of natural ing mode of approach toward. the uppers which increases cutting efilciency. This lateral element in jaw movements is present in normal mastication with natural teeth but has been banished f In full dentures (prohibited to denture wearers because it has tended heretofore to increase the tendency of the lower denture to shift or tilt. The peculiar pitch of the occlusal surfaces of my novel artificial teeth in combination with the character of the occlusal modelling serves positively to stabilize the lower denture upon its base despite the lateral elements in normal jaw movements.

The artificial teeth of my invention afford the lower denture and jaw a definite guidance toward the centric position, which is the normal conclusion of all effective masticatory movements. The occlusal pitch of my novel teeth makes the chewing surfaces substantially parallel to the line of movement in normal mastication, and thus minimizes interference with that movement.

While the invention has been described with respect to a certain particular preferred example which gives satisfactory results, it will be understood by those skilled in the art after understand ing the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new and desired to be secured by Letters Patent is:

1. In combination, coacting upper and lower dentures having sets of premolars and molars respectively, the occlusal surfaces of the premolars and the first molar at one side of the lower denture being pitched downwardly from a high lingual margin to a low buccal margin, and the occlusal surface of the second molar at the same side of said lower denture being pitched downwardly from a high buccal margin to a low lingual margin.

2. In combination, coacting upper and lower dentures having sets of premolars and molars respectively, the occlusal surfaces of the preturc being pitched downwardly from a high buccal margin to a low lingual margin, and the occlusal surface of the second molar at'each side of the upper denture being pitched downwardly from a high buccal margin to a low lingual margin, the respective occlusal surfaces defining single planes approximately.

3. In combination, coacting upper and lower dentures having sets of noninterlocking premolars andmolars, respectively, and said premolars and molars being so positioned that their respective longitudinal axes extend substantially vertically, the occlusal surfaces of the premolars and the first molar at each side of the lower denture being pitched downwardly from a high lingual margin to a low buccal margin, the occlusal surfaces of the premolars and the first molar at each side of the upper denture being pitched downwardly from 'a high lingual margin to a margin to a low lingual margin, the occlusal surface of the second-molar at each side of the upper denture being pitched downwardly from a high buccal margin to a low lingual margin, and the occlusal surfaces of the premolar and molar teeth being provided with grooves and the grooves on corresponding upper and lower teeth being arranged transversely with respect to each other, respectively.

4. In combination, coacting upper and lower dentures having sets of premolars and molars, respectively, the occlusal surfaces of the premolars and the first molar at each side of the lower denture being pitched downwardly from a high lingual margin to a low buccal margin, the occlusal surfaces of the premolars and the first molar at each side of the upper denture being pitched downwardly from a high lingual margin to a low buccal margin, the occlusal surface of the second molar at each side of the lower denture being pitched downwardly from a high buccal margin to a low lingual margin, and the occlusal surface of the second molar at each side of the upper denture being pitched downwardly from a high buccal margin to a low lingual margin, the respective occlusal surfaces defining single planes approximately, the change in pitch between the occlusal surface of each first molar and the occlusal surface of each adjacent second molar being gradual as defined by a relatively smooth transition curve.

5. In combination, coacting upper and lower dentures having sets of posterior teeth respectively, the occlusal surfaces of a plurality of ad-- jacent posterior teeth at one side of the lower denture being pitched downwardly from a high lingual margin to a low buccal margin, and the occlusal surface of a posterior tooth at the same side of said lower denture and at the rear of said plurality of adjacent posterior teeth being pitched downwardly from a high buccal margin to a low lingual margin.

MAX A. PLEASURE.

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