US2391925A

US2391925A - Artificial tooth

Info

Publication number: US2391925A
Application number: US482558A
Authority: US
Inventors: Jacob A Saffir
Original assignee: Dentists Supply Company of New York
Current assignee: Dentists Supply Company of New York
Priority date: 1943-04-10
Filing date: 1943-04-10
Publication date: 1946-01-01
Anticipated expiration: 1963-01-01

Description

Jan. 1, 1946. J sAFFlR 2,391,925

ARTIFICIAL TOOTH Filed April 10, 1943 N VE TOR.

Patented Jan. 1, 1946 UNITED STATES PATENT OFFICE ARTIFICIAL TOOTH Jacob A. Saflir, Kew Gardens, N. Y., asslgnor to Dentists Supply Company of New York, New York, N. Y., a corporation of New York Application April 10, 1943, Serial No. 482,558

13 Claims.

This invention relates to theart of prosthetic dentures and particularly to the artificial teeth comprising the same, embracing within its scope features of tooth construction and adjustment.

The significance of attaining an appropriate positioning of the artificial teeth of a denture is generally acknowledged in the'art. This is especially important with respect to' the coordination of opposing teeth, whether it be between the artificial teeth of one denture, or the artificial teeth which this denture is intended to com- Dlement.

This is effectively illustrated by indications. that the lack of a suitable harmony between the occiusal or biting surfaces of artificial teeth and opposing natural teeth, such as for example,'the condition of interfering or high spots which prevent a satisfactory intercusping, may result in pyorrhea with the attendant possibility of a loss of teeth. Any expedient directed to the relief of excessive trauma on the natural teeth serves to safeguard those teeth against the danger of pyorrhca developing.

The rectification of such conditions has involved considerable difficulties, Thus where the occlusal surface of an artificial tooth has been unduly low, it has heretofore been necessary to reprocess a denture in order to raise the bite, even of a single tooth, and not infrequently this has failed to fully correct the existing condition, it being necessary to disregard one or more other teeth that are to some extent out of function because of the excessive amount oi work involved to entirely slim" ate the dimculty.

Moreover, men completed dentures were placed in the mouth, it was almost inevitably found that the occlusion oi the teeth-"that isthe relationship of thebiting' surfaces oi the upper and lower teeth had changed somewhat during processing from the positions they held when the teeth were retained in wax during the try-in in the patients mouth. Naturally this change often interferes with intercusping or height of the teeth so that in order to reestablish a greater biting surface between the antagonistic teeth, the occlusal surfaces requires adjustment as by grinding.

This treatment, which is often referred to as high spot or spot grinding, destroys some of the fine anatomy oi the occlusion which is intended -for that portion oi the tooth.

In case after case we may see many of the valuable cusps that aid in triturating completely destroyed because the teeth had to be ground in order to eliminate interfering high spots.

Many men Who realize the importance of proper anatomical carving on a tooth and are a little more particular about this important point, try to recarve some of the anatomy but they find it extremely difilcult to restore the original contour which was factory processed in a mold to ive the tooth a final polished precision structure, with calibrated inclined planes.

It is an object of this invention to obviate such diffioulties and uncertainties as hereinabove described, and to readjust artificial teeth surfaces essentially without any destruction of the fine anatomy.

An object of this invention is to obviate the necessity of grinding and generally mutilating the occlusal or labial surface anatomy of teeth involved in the proper fitting and adjustment of a denture,

Another object of this invention is to provide a tooth adapted for an adjustment of its occlusal surface by the biting or intercusping action of the patient.

An additional object of this invention is to provide a tooth adapted for readjustment or reori entation at any interval before or after installa-- tion and/or usage in a dental plate.

Still another object of this invention is to attain a tooth lowered for adjustment in order to afford normal eflectiveness wherein a surface thereof may be oriented, as by raising or lowerine for expedient adjustment in order to afiord an enhanced effectiveness of tooth function.

Other objects, advantages and features of the invention will become apparent from the following consideration and disclosure, especially when read in connection with the accompanying drawing, the elements of which are discussed hereinbelow.

In accordance with the present invention a tooth is obtainable that has a rigid gingival or lingual portion which softens by heating and a rigid occlusal or labial portion which does not soften at the-softening point of the gingival or lingual portion. Thus, the occlusal portion without being injured in any way, can be moved either up or down relative to the softened gingival portion, and similarly the labial portion of an anterior tooth may be oriented with respect to its lingual portion,

There are many materials which are soft enough at reasonable temperatures for molding and yet rigid and hard enough at mouth and food temperatures, from which to make the gingival portion of this tooth. A metal such as Dialoy has a softening range from to F. and

makes a suitable base.- Similarly, if plasticisers and temperature lowering agents are added to most of the thermoplastic resins, their softening range can be lowered so as to be within reason.- able limits for use in this capacity.

The shellac compounds are excellently hard at month temperatures and begin to soften at 150 F. Shellac holds the occlusal portion very securely and-permits moving the occlusal surface a moderate amount upon softening. Styrene is also an excellent plastic for this purpose and its low softening point is around 170 F.

Teeth made as described comprises any suitable material, such as resins, which soften at 140 F. and under can, with care, be manipulated and adjusted in the mouth. Above that point, this work should be done outside of the mouth. It should be noted that the maximum temperature which can be normally tolerated in the human mouth is approximately 135 degrees F. While there are probably instances where a slightly higher temperature has been withstoodin the oral cavity, the maximum in these exceptional cases has never been known to exceed 140 de-- srees F.

The occlusal portion of this tooth is made from any high fusing material having a high softening This seats the occlusal portion higher in the.-

tooth and forces it into a position where it will not be out of harmony with the other teeth. when the gingival portion of the tooth chills, it is again rigid and holds the occlusal portion firmly.

Corrections can also be made outside of the mouth. The dentist can place the dentures in the mouth and then transfer them onto an articulator, which .will carry with it all the error involved. Here, spots that need adjustment can be found quickly; the necessary teeth properly warmed and pressure applied toreseat the occlusal surfaces requiring adjustment.

Or, the dentist may mark the tooth that is high with carbon paper, merely remove the denture, warm the tooth and then, with a blunt instrument, reseat the portion occlusal to where he thinks it should be.

This can be repeated several times, if necessary, until the dentist finds the right spot, If an adjustment has been made that required considerable shortening of the tooth, a mass of the gingival tooth plastic may bulge on the labial and buccal, or even mesial and distal, if there is room for the gingival portion to fiow in that direction. When the tooth returns to a normal temperature, and becomes hard and rigid, any superfluous or protruding material can be ground away as is illustrated later on.

In order to more fully illustrate the invention, reference will now be made to the accompanying drawing wherein certain examples are shown by way of illustration.

Figure 1 is a section of a molar from lingual to buccal.

Figure 2 is a similar section of the same tooth showing the adjustment of the occlusal relative to the gingival portion with protruding or superfluous gingival material.

Figure 3 is the buccal view in elevation of four artificial opposing four natural teeth.

Figure 4 is a similar view to that of Fig. 3 after the four artificial teeth have been adjusted giedhappropriately harmonized with the natural Figure 5 is a cross section from lingua1 to labial of an anterior teeth Figure 6 is a similar view to Fig. 5 after the' labial and lingual portions have been relatively readjusted.

A more detailed description of these will now be given, like numerals indicating similar elements on the various figures of the drawing.

Referring now to Figure l, 3 represents the gingival portion and I the occlusal portion of an illustrative tooth. The occlusal surface 5 of the tooth has the buccal cusp i and the lingual cusp I, The numeral 8 indicates the lingual surface of the occlusal portion 4 of the tooth. I

This occlusal portion, 4, is made of a hard and rigid material such as porcelain, metal, or high fusing resin, which, when warmed to the.temperature required to soften the gingival portion 3 of the tooth, will not become soft and flow, but will remain hard and non-deformable under the necessary pressures and temperatures at which the gingival portion 3 of the tooth is moldable or will flow and yield to pressure. At 8, II and I! are junction points or areas of attachment of the respective hard occlusal portion and the comparatively softenable gingival portion. At II is the base part of the softenable gingival material, and I2 is the buccal surface thereof. The buccal surface of the relatively higher softening occlusal. portion of the tooth is designated ll. The lingual surface of the occlusal portion is designated 8, while the lingual surface of the gingival portion is represented by the numeral ll.

Figure 2 is a similar view to Fig. l, but the gingival tooth portion 3 has been heated to the softening point and pressure has been applied on the occlusal surface, from the direction of cusps 8 and I toward the gingival portion. This caused the gingival material to be displaced and the tooth to become shorter, with the resultant formation of bulges I! and II on the respective lingual and buccal surfaces. Where there are proximating teeth, thisis essentially the only direction the material can flow. Where there are no proximating teeth the now or displacement may be all directions.

After this tooth becomes the proper length, these bulges of material may be trimmed, and the contour brought back to normal as indicated at I8 and 2|. It willbe noted that there has been not the slightest changeinthe anatomy or contour of the occlusal portion 4 of the tooth, so that, although the tooth has undergone considera-ble shortening, it was not at the expense of the occlusal surface anatomy and the tooth will be able to function as originally intended.

Figure 3 illustrates a most common situation when a new denture is first tried in the mouth.

At 30 and 3| are artificial first and second upper bicuspids. Nos. 32 and 33 are artificial first and second upper molars. At It and 35 are natural first and second bicuspids. At 38 and 31 are natural first and second lower molars. As is here illustrated, the only portions of the upper teeth that articulate are the upper first molar 32, whose occlusal surface ll is striking the distal cusp 39 of the first molar, and the mesial cusp of asonoes the second molar 38. It is noted that there is a space M between the occlusal surfaces of the other teeth, due. of course, to the height of the

cusps

38 and 39.

Prior to this invention it was necessary to cut away much of the anatomical portion of the occlusal surface of tooth 32. Only by spending much time, could the dentist recarve this anat-.

omy after grinding it away, although it is doubtful if it ever could be restored as well as before the tooth was mutilated. Or, this condition shown in Figure 3 could be remedied by carving off the natural cusp-

s

38 and 39, which, of course, in most cases is undesirable.

In Figure 4 is shown how well this dimculty can be corrected pursuant to the present invention. Heat was applied to occlusal portion tit and to the gingival portion 32. The heat applied to Ml was transferred to the material directly below it so as to soften it and cause it to yield under pressure. if higher heat is desired, the tooth can be surrounded by cotton rolls, with only the'biting surface exposed, Or, heating can be done outside the mouth, where it is simple to use an instrument to depress or alter the occlusal surface.

Figure 5 illustrates the same principle on anterior teeth. At 50 is the rigid high fusing portion and 5! is the rigid softenable-by-heat material into which 50 can penetrate when an adiustment is desired. At 53 is the labial surface; at 5 3 the lingual surface.

In Figure 6 the outer, higher fusing portion has been pressed lingually, shortening the tooth. It will be noted that excess material from the lower fusing lingual portion exuded at points 55 on the lingual and ill on the labial, These, of course, should be trimmed back to points 58 on the lingual and 59 on the gingival and then polished.

Pursuant to the present invention, an artificial tooth structure is attained which inherently lends itself to the desired adjustment and/or orientation of its portions in a manner to facilitate and appropriately fit in a denture and to provide the harmonized association of artificial teeth relative to each other and to opposing teeth, whether Not to have the patient feel it,

tributable to the invention, and it will be obvlous that they may be the subject of ramification and variation without departing from the scope of the invention. While the invention has been described in accordance with desirable embodiments, many changes and modifications ma be made in the details of construction arid procedure, and in the combination and arrangement of parts, without departing from the spirit of the invention as defined in the following claims,

The term "denture as utilized herein connotes any appliance either fixedly or removably positioned in or attachable to the oral cavity.

peratures encountered in the oral cavity, at least i one of said materials having a softening temperature at which another of said materials is essentially unafiected, whereby said portions are relatively adjustable at the softening temperature of one of said materials and will retain any such relative adjustment.

2. An integral artificial tooth structure com- .prislng two portions, each portion embodying a material adapted for dental prosthesis and man they be natural or artificial. This advantageous result is possible without resort to any operation that might cause the destruction of the fine anatomy of tooth surface that is obtainable through the moulding procedure whereby the tooth is made. Moreover, in addition to its significance in the fitting of the artificial teeth, or dentures embracing these teeth, the invention is applicable to teeth or dentures which have been in use, but require readjustment because of the disalignment which may have developed, for example, through the abnormal growth of any opposing natural teeth. 1

It is accordingly apparent that the invention provides entirely novel and practicable features relating to artificial tooth and prosthetic denture construction and adjustment, substantially eliminating the difficulty and uncertainty heretofore involved in fitting and coordinating the occluding or masticatory surfaces of opposing teeth. A

significant attribute resides in the substantial obviation of the necessity for resorting to such expedients as spot grinding, or in any manner altering the predetermined occlusal or labial anatomy of a given tooth, whether it be artificial or an opposing natural tooth, in order to attain requisite compatibility between opposing teeth.

Many other features and advantages are atifesting substantial rigidity and hardness at maximum temperatures encountered in the oral cavity, one of said materials being thermoplastic relative to the other material and having a moldable softening temperature substantially differentiated from any softening temperature of the other material, whereby said portions are relatively adjustable at the-moldable softening temperature of said relatively thermoplastic material portion and will retain any such relative adjustment.

3. An artificial tooth molded in accordance with a predetermined contour surface comprising an occlusal portion and a thermoplastic gingival portion, both of said portions being prosthetic dental materials manifesting requisite rigidity and hardness at maximum temperatures encountered inthe oral cavity, said gingival portion having .a moldabl softening temperature at which said occlusal portion is essentially unaffected, whereby said occlusal portion is adapted for adjustment relative to said gingival'portion at the softening temperature of the latter and said portions will retain any such relative adjustment.

4. An artificial tooth comprising a, labial portion, and a lingual portion having a moldable softening temperature in excess of the maximum temperature encountered in the oral cavity, both portions being materials adapted for dental prosthesis and manifesting rigidity and hardness at maximum temperatures encountered in the oral cavity, the moldable softening temperature of the labial portion being relatively high and the softening temperature of the lingual portion being relatively low, whereby said labial portion may be adjusted relative to the lingual portion at the softening temperature of the latter, and said portions will retain any such relative adjustment.

5. An artificial tooth comprising a thermoor predetermined masticatory surface and comparatively rigid at the softening temperature or said gingival portion, both portions being prosthetic dental materials hard and rigid at maxi mum temperatures encountered in the oral cavity. said occlusal portion being superimposed upon said thermoplastic gingival portion in interlocked attachment, whereby said occlusal portion is adapted ior adjustment or altered orientation relative to said gingival portion, at the softening temperature of the latter and said portions will retain any such relative adjustment.

6. In a denture, at least one artificial tooth comprising in integral combination a thermoplastic gingival portion attached to said denture and an occlusal portion of predetermined masticatory surface, both portions being materials adapted for dental prosthesis and hard and rigid at maximum temperatures encountered in the.

oral cavity, said gingival portion being moldably plastic at a temperature above the maximum oral cavity temperature, said occlusal portion being relatively unaffected by heat, whereby said artificial tooth is adapted for length adjustment and realignment relative to an opposing denture at the molding temperature of said gingival portion, said portions retaining any such relative adjustment.

7. The method of adjusting a denture embodying atleast one artificial tooth having an occlusal and a thermoplastic gingival portion, said tooth being rigid at maximum temperatures encountered in the oral cavity, said gingival portion having a moldable temperature at which said occlusal portion is unaffected, which comprises supplying heat to said tooth for-rendering the gingival portion thereof moldable, adjusting the relative position of said occlusal and gingival portions at the moldable temperature of said gingival portion to correspond with the occlusal surface of an opposing denture and permitting said gingival portion to cool to its rigid state.

8. The method of adjusting artificial teeth of a denture embodying artificial teeth each having a asoneao which comprises heating the tooth to be adjusted to the moldable temperature 01 the gingival portion, forcing said occlusal portion into harmonious engagement with the corresponding tooth or teeth in the mouth by the biting action of the patient, permitting said gingival portion to become rigid by cooling, and trimming of: any resulting contour irregularities in said gingival portion.

9. In a denture at least one artificial tooth comprising in integral combination a thermoplastic lingual portion attached to said denture and a thermoset labial portion derived from a material adapted for dental prosthetics, said lingual portion being a substance adapted for dental prosthetics from the group consisting of metallic materials'and resinous materials of natural and synthetic derivation, both portions being materials adapted for dental prosthesis and hard and rigid at maximum temperatures encountered in the oral cavities, said lingual portion being mouldably plastic at a temperature above the thermoplastic gingival portion attached to said denture, and a thermoset occlusal portion in integral combination with said gingival portion, both of said portions being essentially hard and rigid at maximum temperatures encountered in the oral cavity, said gingival portion having a moldable temperature above the maximum temperature encountered in the oral cavity, said 00- clusal portion being relatively unafiected by heat,

maximum. oral cavity temperature, said labial portion being relatively unafiectedat the softening temperature 01 said lingual portion, whereby said artificial tooth is adapted for readjustment and for realignment relative to an opposing denture at the moulding temperature or said lingual portion, said portions retaining any such relative adjustment.

10. The method of adjusting a denture embodying at least one artificial tooth having a. labial and a thermoplastic lingual portion, said tooth being rigid at maximum temperatures encountered in the oral cavity, said lingual portion having a moldable temperature at which said labial portion is substantially unaffected, which comprises supplying heat to said lingual portion for rendering the same moldable, adjusting the relative position of said labial portion at the moldable temperature of said lingual portion, and permitting said lingual portion to cool to its rigid state.

11. An artificial tooth as in claim 3 wherein the occlusal. portion is a thermoset synthetic resin and the gingival portion is a thermoplastic synthetic resin.

12. An artificial tooth as in claim 3 wherein the occlusal portion is porcelain and the gingival portion is a synthetic resin.

13. An artificial tooth as in claim 4 wherein the labial portion is porcelain and the lingual portion is a synthetic resin.

JACOB A. SAFFEIR.

Certificated Correction Patent No". 2,391,925. I January 1, 1946.

JACOB A. SAFFIR 1 his hereby certified that errors appear in the printed specification of the above numbered patent requirin correction as follows: Page 1, second column, lines 28 and 29, strike out the Words owered for adjustment in order to'afford normal eifective ness; page 2, first column, line 55, for portion occlusal read occlusal portion; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice..

Signed and sealed this 21st day of May, A. D. 1946.

[SEAL] LESLIE FRAZER,

First Assistant Commissioner of Patents.