US 3161956 A
Description (OCR text may contain errors)
1964 c. P. VAN COURT ETAL 3,161,956
METHOD AND APPARATUS FOR ADAPTING DENTURES Filed May 2, 1960 R m m M N E W 2 m 0 W Lm R A 6 AA H I Y B Wf/ QO ATTORNEY5 United States Patent 3,151,956 NETHQD AND APPARATUS FUR ADAPTlNG BENTURES Carl P. Van Court, Canoga Park, and Harold E. Kinsman,
Southgate, Caliii, assignors to Air-Balance Corporation,
a corporation of California Filed May 2, 1969, Ser. No. 26,109 3 Claims. (Cl. 32-19) This invention relates to the fabrication of artificial dentures and more particularly to an improved method and apparatus for establishing angular mandibular-maxillary relationships to the end that superior adaptability and comfort of finished dentures may be achieved.
This invention constitutes an improvement over the method and apparatus for adapting dentures set forth in our United States Patent Number 2,773,308, issued December 11, 1956. In this latter-mentioned patent, the extreme importance of having functional stresses and occlusal pressures between the mandibular and maxillary dentures equalized and maintained is set forth. Unequal and incorrect pressures not only result in shifting of the completed denture bases on the alveolar ridges producing occlusal disharmonies, soreness, and possibly much pain, but can cause the more serious result of bone dystrophies; that is, the osseous foundations change and eventually tend to render the original dentures out of harmony.
All or" the various objects and advantages of our prior United States Patent 2,773,308 are achieved by the improved method and apparatus of this invention, and the subject matter of said patent is accordingly hereby incorporated in this application by reference.
in the method set forth in our prior United States patent, proper angular relationship between the mandibular and maxillary trays or bite blocks in a lateral direction as well as in an anterior-posterior direction is achieved by employing a flexible iluid chamber disposed between the opposing bite rims of the trays and inflated to a pressure substantially equal to the physiologic pressure corresponding to the diastolic cardiovascular pressure characteristic of the patient. This particular presstu'e is determined by measuring the actual fluid pressure in the chamber after instructing the patient to close his mouth sufficiently to cause an anterior pin structure on the maxillary tray to touch lightly a cooperating plate secured to the mandibular tray.
With the pressure recorded, it is then possible to subsequently hold the mandibular and maxillary bite blocks in a proper angular relationship while applying quick setting material to distal support plates secured to the ends of the mandibular block. Hardening of this material while holding proper pressure in the chamber thus fixes the mandibular and maxillary blocks in proper relationship to each other notwithstanding possible tiring of the patients muscles resulting in loss of muscle tonus which would normally chan e the desired relationship. In other words, the fluid chamber itself serves as a substitute for the natural physiologic pressure of the particular patient so that extremely accurate relationships between the opposing blocks can be achieved.
While this prior method will enable the fabrication of properly fitting dentures, its success is dependent to a large extent on the proficiency of the particular dentist in carrying out the method steps.
With the above in mind, it is a general object of tie present invention to provide an improved method and apparatus for adapting artificial dentures involving fewer steps than have heretofore been deemed necessary and yet providing accurate mandibular-maxillary relationships to enable the fabrication of dentures of equal or even superior quality to those provided by prior methods.
More particularly, it is an object to provide an improved method and apparatus for establishing lateral and anterior-posterior angular mandibular-maxillary relationships in cooperation with a conventional centric anteriorposterior and vertical indexing pin to the end that dentures may be created in which the physiological forces are related to the vascular pressures and the sensory nerve endings of the alveolar ridges of the patient to establish maximum comfort for the patient.
In accordance with the improved method of this invention, rather than fixing the mandibular and maxillary bite blocks or trays in a set relationship with each other by means of quick setting material at the distal ends of the trays in cooperation with an anterior pin and plate structure as described in our above-mentioned United States patent, a quick setting material in fluid form is pumped directly into a fluid chamber disposed between the opposing bite rims of the bite blocks. The pressure of this quick setting material while in fluid form is maintained at a value substantially equal to the physiologic pressure corresponding to the physiologic pressure characteristic of the patient until the quick setting material has hardened. Thus, the angular relationship of the mandibular and maxillary bite blocks are eilectively fixed by hardening of the quick setting material within the entire fluid chamber rather than by hardening of quick setting material at the distal points.
There is thus eliminated the need for a modified anterior indexing pin and plate structure in cooperation with specially designed blocks as well as corrugated support plates at the distal ends of the blocks. Further, the steps of first recording a physiologic pressure characteristic of the patient and then re-infiating a flexible tubular chamber to such pressure for subsequently establishing the desired angular relationships of the blocks are eliminated. As a consequence, the entire method includes less steps and is thus more readily learned and capable of being more effectively practiced by the dentist.
A better understanding of applicants improved method and apparatus will be had by now referring to the accompanying drawings, in which:
FIGURE 1 is an exploded plan view of the mandible and maxilla with associated bite blocks and centric assembly;
FTGURE 2 is a plan view of the mandibular bite block with a flexible fluid chamber in position; and,
FIGURE 3 is a cross-section of the mandible and maxilla with associated bite blocks, centric assembly, and inflatable fluid chamber in a patients mouth, the various referred-to portions being shown looking in the general direction of the arrows 3-3 in the respective diagrams of FIGURES 1 and 2.
Referring first to FIGURE 1, there is illustrated in plan view the mandible 10 and maxilla 11 of a patients month including the generally arch shaped alveolar ridges 12 and 13 respectively. As shown, suitable mandibular and maxillary bite blocks 14 and 15 are fitted over the alveolar ridges in such a manner as to properly register when the patients mouth is closed in a normal comfortable position.
A conventional centric assembly is provided for maintaining proper anterior-posterior and vertical spacing. This assembly includes a mandibular plate 16 irnbedded in a position co-planar with the plane of the arch shaped mandibular bite block 14. Plate 16 includes a slide plate 17 provided with a centric pin receiving opening 18 and suitable means, such as a screw 15?, for positioning slide plate 17 in a desired set position with respect to the mandibular plate 16. The maxillary bite block in turn is provided with a maxillary plate 20 including a projecting pin 21 receivable within the opening 18 when proper anterior-posterior and vertical relationships have been established between the respective bite blocks.
In accordance with one feature of the present invention, the mandibular plate 16 is modified from the conventional mandibular centric plate by the provision of three fastening openings 22, 23, and 24 disposed adjacent the inside periphery of the mandibular bite block 14. These openings define the vertices of a triangle. Their purpose will become clearer as the description proceeds.
Referring now to FIGURE 2, there is: shown the mandibular bite block 14 with its arch shaped upper bite rim substantially covered over its entire area by a flexible fluid chamber 25. As shown, the chamber 25 includes an elongated neck 26 protruding from its front central portion and terminating in a quick connect and disconnect coupling 27. The inner peripheral sides of the arch shaped flexible fluid chamber 25 include flattened tab portions 22, 23', and 24, provided with openings positioned to register with the fastening openings 22, 23, and 2 on the mandibular centric plate of FEGURE 1. By thisarrangement, suitable securing means may be passed through the registered openings for securing the inflatable fluid chamber 25 in position. Alternatively or additionally, further tabs about the outer peripheral side of the flexible fluid chamber 25 as at 28 and 29 may be provided. These in turn are secured to the outer surface of the mandibular bite block by any suitable pin means.
The relationship of the above-described components in FIGURES l and 2 will be better understood by referring to FIGURE 3 showing the mandibular and maxillary bite blocks in position over the corresponding alveolar ridges 12 and of a patients mouth. Also shown in cross section is the fluid chamber 25 inflated with a quick setting material 39. The actual bite rims of the mandibular and maxillary bite blocks 14 and 15, themselves, are preferably provided with V-shaped grooves 31 and 32, respectively. When the flexible fluid chamber 25 is infla-ted, its engaging portions will conform to these V-shaped grooves as shown.
With reference now to all of the'figures, the general method of establishing the desired mandibular-maxillary relationships for enabling the fabrication of properly fitting dentures including the novel steps of the instant invention will be described. In initially making up the mandibular and maxillary bite blocks 14 and 15, snap impressions are first made of the patients alveolar ridges in a conventional manner. From these impressions, plaster models of the month are created and custom-fitted trays formed. These custom-fitted trays in turn are employed to make master impressions. In making these master impressions, certain of the method steps set forth in our above referred-to US. patent are preferably employed. Thus, a suitable fluid chamber is filled with air or other fluid for applying a pressure between the opposing trays themselves to urge the trays and impressiontaki-ng material therein into engagement with the alveolar ridges at a pressure corresponding to the diastolic cardiovascular pressure characteristic of the patient.
From these latter impressions, master models are made of hard stone and positioned on a suitable articulator. From these master models, the bite blocks 14 and 15 are formed, and a primary bite is obtained from the bite blocks by actually fitting the same within the patients mouth.
After the primary bite has been obtained, the bite blocks are returned to the master models and these master models then re-positioned on the articulator to insure proper anterior-posterior and vertical relationships between the bite blocks. l/hen properly adjusted, the pin 21 of FIGURE 1 is caused to register in the centric pin receiving opening 18 or" the mandibular slide plate 17 by suitably sliding this plate to the proper position and tightening the screw 1?. The centric plates and accompanying assembly thus fix the desired anterior-posterior relationship as well as the vertical spacing of the bite blocks.
All of the foregoing is normal operating procedure.
In accordance with further conventional or prior art steps in the method, the bite blocks are then IC-POSlllOIlC-d in the patients mouth and with the patient holding the pin 21 in the pin receiving hole 18, suitable plaster of Paris matrices are applied to the lateral sides of the bite blocks While the patient holds the centric. The hardened plaster of Paris will then fix the bite blocks in a relationship with respect to each other which will be correct with respect to anterior-posterior and vertical spacing. However, there is no assurance of correct lateral or anteriorposterior ang lar balance or relationship.
The above will become clearer by reference to applicants FIGURE 3, wherein it will be evident that in the absence of the fluid chamber 25, the patient must eflectively balance the bite blocks about the centric pin 21. Unless this pin is geometrically located at the exact center of pressure exerted by the patient in bringing his mandible up towards his maxilla, there is no assurance that the lateral and/ or anterior-posterior relationships of the mandibular and maxillary blocks will be proper. In other words, it is possible that the mandibular bite block 14- may cant or tilt slightly from a normal axis AA towards an inclined axis A'-A' or about axes extending in anterior-posterior directions. If such occurs and the plaster of Paris matrices on the two lateral sides of the mouth set, the resulting bite blocks will not be properly angularly oriented with respect to lateral and anterior-posterior balance although the bite blocks will be properly oriented with respect to those anterior-posterior and vertical positions fixed by the centric assembly.
. The resulting dentures fabricated from possible incorrectly established angular relationships of the bite blocks can result in unequal pressures on sides of the mouth when the dentures are worn. The result is unequal pressure on the alveolar ridges which produce the aforementioned occlusal disharmonies and soreness, as well as pain. Moreover, such unequal pressures can result in the more serious problem of bone dystrophies. Thus, the osseous foundations change and rather than adjust to the particular pressure, are often prone to atrophy more than necessary so that the unequal pressure distribution is shifted from one side of the mouth to the other. The original dentures are thus rendered completely out of harmony with the patients alveolar ridges after a short period of use.
It is believed the foregoing is the primary cause for repeated calls back to a dentists ofiice for refitting of dentures.
The particular problem of angular unbalance which is the basic cause of the improperly fitted dentures is overcome, as mentioned by applicants prior method as set forth in our prior United States patent. That is, the quick setting material at the distal ends of the mandibular and maxillary bite blocks is only applied and caused to set with the presence of the inflatable fluid chamber between the bite blocks inflated to the proper pressure to insure balanced or equal pressures on all areas of the mouth.
The same effective results are achieved in accordance with the method of the present invention by employing the particular inflatable fluid chamber 25 depicted in FIGURES 2 and 3. Thus, rather than applying quick setting plaster of Paris or other quick setting material to the distal ends of the bite blocks, the fluid chamber 25 itself is inflated with quick setting material 30 in fluid form to a pressure which is absolutely uniform and equal about the entire engaging areas of the opposed bite block rims. This uniform pressure is carefully controlled to a value at which the centric pin 21 will lightly engage the centric pin receiving opening 18. In effect, the flexible fluid chamber seats the pin 18 in the opening and in cooperation with the patient, the seating pressure corresponds to the diastolic cardio-vascular pressure characteristic of the patient himself.
The quick setting material 36 itself is of a nature that it will harden in from 20 to 40 seconds so that exact angular balance is fixed in a period of time considerably shorter than is the case when plaster of Paris matrices are employed.
With correct angular balance achieved, the doctor may then remove the bite blocks and replace them on the master stone models. These master stone models are then re-positioned on the articulator in accordance with their pro-established relationship. The entire fluid chamber together with the hardened quick setting material therein is maintained between the bite blocks when the master stone models are repositioned on the articulator. The V- shaped grooves in the bite rims enable exact re-positioning of the bite blocks and the fluid chamber to correspond to their positions when in the pat-ients mouth.
The dentures can then be fabricated by conventional subsequent processing.
By employing the above described improved method, the fixed relationships between the mandible and maxilla can be consistently repeated with a degree of accuracy never heretofore achieved by the old conventional methods of employing plaster of Paris or other quick setting material at the distal ends of the bite blocks and relying on the patient to hold a fixed angular balance.
It is evident that the improved method of this invention greatly simplifies the steps of insuring angular balance of the bite blocks. The resulting dentures are substantially perfectly adapted to the patients mouth, particularly with respect to angular balance, and the aforementioned problems of bone dystrophies and unequal pressures are avoided.
It should be understood that the method can also be employed in re-adapting dentures already manufactured by positioning the fluid chamber between the mandibular and maxillary dentures themselves rather than the bite blocks.
In the following claims, the phrase physiologic pressure corresponding to the diastolic cardio-vascular pressure characteristic of the patient includes that pressure which is correlated to the sensory receptor nerve endings of the alveolar ridges of the particular patient, and which is controlled by the neuro-muscular system of the patient. This pressure in practice is always adjusted to take into consideration the condition of the supporting surface. The physiologic pressure for the individual is thus es ablished, assuming the necessary control to prevent distortion or displacement and at the same time utilize the maximum pressure necessary to establish muscular tonus in the seating of the mandible in the glenoid fossa.
Further, the term bite block is meant to include bite blocks employed in adapting partial or complete dentures and bridges, and re-adapting the partial or completed dentures themselves respectively. The term bite blocks as used in the method claimed is also meant to include equivalent members such as trays or already completed dentures which fit the alveolar ridges to enable the desired mandibular-maxillary angular relationships to be established.
What is claimed is:
1. An improved method of establishing angular man dibular-maxillary relationship in cooperation with a cendexing pin in previously established anterior-posteriorvertical position; positioning fluid receiving means in collapsed condition over the rim area only of said mandibular-bite block; pumping a quick setting material in fluid form into said fluid receiving means to provide a uniform pressure between the opposed bite rims of said bite blocks having a value substantially equal to the physiologic pressure corresponding to the diastolic cardio-vascular pressure characteristic of the patient; maintaining said pressure until said quick setting material has hardened whereby said hardened material will together with said centric pin enable re-establishment of the angular relationship of the mandible and maxillary in the subsequent fabrication of dentures; and thereafter transferring the assembly of bite blocks and fluid receiving means with the hardened material therein to an articulator for further processing.
2. An improved apparatus for establishing angular mandibular-maxillary relationships for adapting dentures comprising, in combination: arch shaped mandibular and maxillary bite blocks adapted to fit over the corresponding alveolar ridges of a patient, said bite blocks having opposed V-shaped grooves in their rims; a flexible fluid chamber of generally arch shaped configuration corresponding to the arch shape of the bite rim of said mandibular bite block disposed between said bite blocks in alignment with said V-shaped grooves; means forming a part of said fluid chamber securing said chamber over substantially the entire area of said mandibular bite rim; a quick setting material in a hardened state located in said fluid chamber and forcing said fluid chamber into said opposing V-shaped grooves to apply a uniform pressure between the opposing rims of said bite blocks; and means for introducing said quick setting material in fluid state into said fluid chamber; said hardened material providing means for subsequently reestablishing the angular relationship of said mandibular and maxillary bite blocks to enable subsequent fabrication of said dentures.
3. An apparatus according to claim 2, including a centric assembly secured to said bite blocks, said centric assembly including a mandibular centric plate lying in the plane of the arch of said mandibular bite block and secured thereto, said plate including an auxiliary slide plate having a centric pin receiving openings; means for adjusting the position of said slide plate with respect to said mandibular plate and for securing said slide plate to said mandibular plate in a set position; and a maxillary centric plate secured to said maxillary bite block and including a centric pin extending substantially normally to said mandibular centric plate and received in said centric pin receiving opening when the anterior-posterior and vertical relationships of said bite blocks have been established, whereby said uniform pressure may be determined by that pressure exerted by said patient through the medium of said bite blocks to said fluid chamber just sufficient to effect contact of said centric pin with the bottom of said centric pin receiving opening, said pressure being substantially equal to the physiologic pressure corresponding to the diastolic cardio-vascular pressure characteristic of said patient.
References Cited in the file of this patent UNITED STATES PATENTS 2,562,106 Leathers July 24, 1951 2,773,308 Van Court et a1 Dec. 11, 1952 2,937,443 Skinner May 24, 1960