US2849794A - Artificial molar - Google Patents

Description

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I ARTIFICIAL MOLAR Filed Feb. 21, 1955 Y INVENTOR. Cay-Karel TF/VZER BY I United States Patent ARTIFICIAL MOLAR Gerhard Tanzer, Dresden-Weisser Hirsch, Germany, assignor to VEB Keradentawerk, Railfeisenweg, Radcberg, Germany Applicafion February 21, 1955, Serial No. 489,563

Claims. (Cl. 32-8) My invention relates to improvements in artificial molar teeth for dentures, for example plates.

It is an object of the invention to improve the shape ofartificial molars such as to considerably diminish the tilting of molars liable to originate by the movements of chewing, whilst nevertheless holding the food well and breaking it into small pieces.

Other objects and structural details of the invention will be apparent from the following description when read in conjunction with the accompanying drawing forming part of this specification, in which is schematically shown by way of example a view, partly in section, of a molar in accordance with my invention.

The tooth 1 may be made of any suitable artificial material, for example of a mineral substance, of an artificial product of condensation as a polymer, or of a mixture of such substances. The tooth is provided at its lower side with an opening 2 which is wider towards the center of the tooth. This opening serves for securing the tooth to the plate of the denture. The ledge shaped, raised, undulatory rim 3 surrounding the grinding surface rises and falls, making an angle a of about 1820 with the horizontal plane. This inclination of the rim 3 extends in sagittal direction relative to the horizontal plane. In transverse direction, the inclination is about 3-5. Within the rim 3 the tooth is provided with ridgeforrning protuberances 5, the side faces 4 of which make an angle 3 of about 30-45 with the horizontal plane. The sharp crests 6 of these ridges are lower as much as A than the ledge shaped rim 3.

By arranging the crests 6 of the protuberances below the rim 3 the molars are able to move in a circumscribed path without being hindered by the protuberances such that parts of the food diificult to be attacked are worn down by the lower but steeper protuberances without removing the denture from its place.

Whilst the sides 4 of the protuberances 5 are shown to be plane faces and the crests 6 between two neighboured side faces to be horizontal straight lines, the protuberances may be shaped otherwise, for example they may have irregular forms. The molars for the lower denture may be made narrower than it is usual, in order to allow more liberty to move for the tongue than it has been the case with former artificial molars.

If desired the molar according to my invention may comprise parts made of different materials, for example it may comprise an inner part made of another material than the outer part.

2,849,794 Patented Sept. 2, 1958 surface of artificial molars, on the one hand for improving the chewing force of the person wearing the denture, and on the other hand for diminishing the wobbling especially of total dentures. All artificial teeth hitherto in use have drawbacks which mainly arise from the fact, that flat molars require higher chewing forces than teeth provided with high cusps or ridges. Cusps or ridges which sometimes make an angle up to 32 with the horizontal plane are liable to press the denture away from the jaw during the chewing process. the last phase of the bite the lower denture is moved back to its normal position by the coacting upper teeth, various thrusts arise causing a considerable damage to the tissues under the denture. Infiammations and even deformations of the jaws arise, which again cause defective chewing ability requiring a new denture. By the improved tooth according to my invention these drawbacks are eliminated.

I have described preferred embodiments of my invention, but it is understood that this disclosure is for the purpose of illustration and that various changes in shape, proportion and arrangements of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim is:

I. In an artificial molar having a grinding surface,

the combination of a ledge-shaped raised rim surrounding the grinding surface in wave-like fashion, and edge-forming protuberances on said surface, said protuberances having inclined side faces, the crests of said protuberances 'being situated below said rim, and said waves and said side faces including difierent angles with the horizontal plane.

2. In an artificial molar as claimed in claim 1, wherein said waves include a smaller angle with the horizontal plane than the side faces of said protuberances.

3. In an artificial molar having a grinding surface, the combination of a ledge-shaped raised rim surrounding the grinding surface, and edge-forming protuberances on said surface, the highest points of said protuberances being situated below said rim, and said rim being inclined in sagittal direction relative to the horizontal plane.

4. In an artificial molar as claimed in claim 3, wherein the inclination of said rim is about 18-20.

5. In an artificial molar having a grinding surface, the combination of a ledge-shaped raised rim surrounding the grinding surface, and edge-forming protuberances on said surface, the highest points of said protuberances being situated below said rim, and said rim being inclined in transverse direction relative to the horizontal plane to an extent of about between 3 and 5.

References Cited in the file of this patent UNITED STATES PATENTS 2,104,459 Gysi Jan. 4, 1938 2,417,965 Beresin Mar. 25, 1947 2,598,769 Donavan June 3, 1952 Even when during

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