US2608760A - Preformed dental arch - Google Patents

Description

Sept. 2, 1952 E. H. ZAHN PREFORMED DENTAL ARCH Filed April 25, 1949 FIG.. I

(Ittornegs important that, despite the flexing of the sections inwardly or outwardly in the occlusal plane, each arch must be relatively inflexible upward or down. For this latter reason, I have found that the use of a hinge bar that is symmetrical in both its major and minor axes and has a uniform crosssection along its length is most desirable and efficacious.

Referring particularly to Figures 1 and 2 of the drawings, I show a dental arch having a multi-toothed anterior block [0 and the multitoothed posterior blocks I2, 02. The teeth of each block are preferably joined securely together in the proximal region to make the blocks substantially inflexible between their ends. Such blocks, I have found, are most effectively produced by precision casting methods and the use of synthetic or plastic polymerizable materials whereby life-like reproductions can most conveniently be made. In such casting operations,-..through"the use of a withdrawable core member, I form mortises or sockets M, which are'accurately located and preferably enter the body of the end tooth of a block in the proximal contact region The posterior teeth blocks 42 need only have 4 bending of the bar is not interfered with by the adjacent tooth material which usually curves away from the point of contact. Because of the relative inflexibility of the bars 20 out of the plane of bending, such an operator will not normally by manual pressure distort one section upward relative the other.

In the case of a pair of matched dental arches having proper, predetermined occulsion therebetween, accurate adjustment is'entirely possible and quite easy of attainment. The operator moves, let us say, the lower posterior blocks outa mortise M on the forward end in the first bicuspid tooth it, whereas the anterior block H) has a mortise H5 at the ends in each cuspid tooth l8.

=The dowel-like hinge bar 29 of Figure 5, which is; rectangular in cross-section, fits into the mortises M of teeth l6 and i8 as when a posterior block i2 is brought into abutment with the anterior block IE3. The hinge bar 26 closely fits the mortises to eliminate-looseness and prevent racki g of the blocks relative to each other. The hinge bars may be secured in themortises cementitiously, on occasion, although I have found that insuring a close flt between bar and opening is usually sufficient.

'Itwill be seen in Figure 5 that the bar 20 is symmetrical in its major axis A-A, its minor axis-B-B, and its longitudinal axis CC. This characteristic is important because it insures that when the bar 29 has its. longitudinal axis C 'C bent in the plane of axis 3-13, the bend will not tend to distort the bar out of that plane. In other words, the bend should be in a substantially flat plane corresponding generally to the occlusal plane and bending out of that plane is resisted by forming the bar so that its width is greater than its horizontal thickness.

Such a bar 20 is placed between the blocks l0 and I2 so the width is upright and the thickness is substantially horizontal. The ends of the bar are embedded in the cuspid and first bicuspid teeth of the abutting sections and the bar spans between such teeth at the proximal contact region where it is eifectively concealed and is not exposed to view.

Bar 20 is most eifective when formed of a metallic material that is rust-proof and has a ductility that permits manual flexing in the horizontal plane but is practically inflexible out of that plane by normal manual pressure.

An operator starting to produce a denture and having the assembly of Figure 2, determines the jaw. breadth that this arch is to accommodate. He adjusts the dental arch by manually flexing or bending the hinge bars 20 inward or outward to move the posterior sections relative the anterior section in the occlusal plane. mally the abutment between an anterior and a posterior section is not broad or substantial, the

Since nor ward a desired amount and then moves the upper posterior blocks a like amount, retaining the previously had occlusion between the arches.

Bar 24 of Figure 6 is an alternative form of the shape of a fully symmetrical oval. Bar 26 seen in Figure 7 is I-shaped by reason of flanges 21 and is likewise symmetrical in the sense employed herein. The further alternative form of hinge bar' 23. of Figure 8 is similar to the rectangular bar 29, except that its edges are beaded. I

at 38. The bars of Figures '7 and 8 are some;

what more stiff than bar 23 but are so formedas to nevertheless be manually flexible inthe plane 3-3 and relatively inflexible to' manual pressure out of that plane. It. will be understood that the use of bars 2.4, 26 or 28 will necessitate the formation of mortises that are shaped to receive such bars. v

I have found that this invention produces many advantages that are material in the production of artificial dentures. By .the use of arches having my invention incorporated easy accommodation of a wide range of sizes inthe human mandible and maxillae can behad with I a single standard arch. This means that the stock of arches that must be maintained in a laboratory is relatively small and expense of large inventories is avoided. The setting-up of teeth can be accomplished with help of materially less skill than in the case of the present conventional methods and in considerably less time by such unskilled technicians. The use of preform'ed anterior blocks permit the selection and trying-on of the block to the patient'for size,

color and tooth arrangement without elaboratelaboratory work having to be done beforehand,

thus eliminating at least-one visit of the patient. The esthetics of supplying artificial dentures is materially enhanced and patient satisfaction is more easily attained. Another advantage that I have noted to' be of importance is that the laboratory worker is precluded from changing the vertical dimensions and altering occlusion during processing of the teeth-in other Words, he can follow a bite register furnished and does not risk changing the bite between matched upper and lower arches. Balanced occlusion can beobtained oncein a master set and then can be reproduced time after time in the preformed arches having such balanced-occlusion and maintained despite alterations of the archwidth and with the avoidance of spot grinding and milling 7. which are'time-consuming and expensive operations at present. w 7

Having thus fully described and explained my invention, I claim:

1. A dental arch, comprising: three end-abut ting inflexible blocks of artificial teeth, the teeth of each block being securely fused to its neighbors in the interproximal-region, each block forming an integral, self-supporting assembly inde-li pendently of gum denture structur wa flrstoi. -saidblocks being composed of the posterior teeth on one side from a point in the cuspld-bicuspid area rearward, a second of said blocks being composed of the posterior teeth on the other side from a point in the cuspid-biscuspid area rearward, and the third of said blocks being composed of the; anterior teeth between said first and second blocks, said blocks having openings in their adjacent abutting ends; and, means joining said first block to said third block and said second block to said third block, said means comprising an elongated, transversely and longitudinally.

symmmetrical metal hinge bar embedded at its ends in said openings in said blocks contiguous to the interproximal region on each side of the line of abutment, said hinge bar having larger transverse dimensions vertically than horizontally and being manually flexible in a substantially horizontal plane and relatively inflexible out of said plane by normal manual pressure.

2. The invention according to claim 1 in which the hinge bar is a transversely oblong rectangular bar positioned so that its greatest transverse dimension is upright. 1

3. The invention according to claim 1 in which the hinge bar is a bar having beaded edges throughout its length and so positioned that its width is upright.

4. The invention according to claim 1 in which the hinge bar is a bar having an I-shape in crosssection throughout its length and so positioned that its width is upright.

- ERIC H. ZAHN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,302,499 Bennett May 6, 1919 1,449,631 Stern Mar. 27, 1923 1,461,305 Brookes et a1 July 10, 1923 1,947,026 Wharton Feb. 13, 1934 2,350,196 Safllr May 30, 1944

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