US 2935791 A
Description (OCR text may contain errors)
May 10, 1960 W. J. ADAMS DENTAL PROSTHETIC DEVICE 2 Sheets-Sheet l Filed March 27, 1957 R m ms mm 2 w u J. H W 2 m F @MZJQ/M ATTORNEYS y 0, 1960 w. J. ADAMS 2,935,791
DENTAL PROSTHETIC DEVICE Filed March 27, 1957 2 Sheets-Sheet 2 FIG. 5
INVENTOR WILEY J. ADAMS ATTORNEYS This. invention relates, to artificial dentures; and, more. particul-arly toartificial.dentures having improved maxillary andmandibular, molar and bicuspid metal" teeth.
Artificialdentures, owing to the wide use of such prosthetic. devices, have been the. subject. of intensive study and development for. years. Despite the eliorts exerted in this field, 'aIIZlfiClEtL'dGIIlllIES, now in use areonly about fifteen percent. as eflicient' as natural teeth. The artificial teeth. ernployedinldentures have been, for the most part, formedofporcelaih,,though in recent years, teeth formed of. acrylic. resins have, been-utilized. Artificial teeth composed. ofj these. materials. have been incapable of cutting and grinding food. to], the. fine degree that is possible with, natural teeth. Numerous attemptshave been .made to provideartificial teeth composed either entirely of metal or offsyntheticaresinous,or other materials having metallic; inserts. in, the. oeclusa-l; surfaces. Such artificial teeth relied. solely. uponthe inherent strength of the metal to withstandv the pressures, exertedby. the jaw in use and were, not constructed'ina manner such that eflicient cutting and grinding, off food. were accomplished; Accordingly; metallic teeth or teethv having metallic elements. in the occlusal surfaces. thereof have never been. adopted commercially. v
This .inventionlis based upon the discovery that artificial dentures, aving metal. maxillary andmandibularv molars and bicuspids having sharp cusp or. cusp-like serrated elements, and, deep sulci; or sulci-like grooves in the occlusal surfaces. and which, when each maxillary bicuspid and. molar. tooth is. completely interdig itated with the correspondihglmandibular bicuspid and molar tooth, are highly efficient incutting'and grinding food. The efliciency of the artifici'alJdentures of this invention is attributable, to, theme. oflmaxillary. and mandibular bicuspids andmolars. having sharp cusp-like members in the occlusalsurfaceswhich are polyhedral in shape and which haveisharp apjcesj and adgesfat the intersection of the inclinedjsurfaces of'tlie. polyhedral elements. The bases of these polyhedral cuspsj are polygonal, having three or more sides, butitis preferred to employ tetrahedraltor pentahedfralj cusp members. Inconjunction with the. foregoing essential" structural features, the bicuspids and molars} employed'in this invention are characterized by exception-ally deep .sul'ci between the 1 spaced polyhedral elementsinltheocclusal' surfaces. The polyhedral cusplike members and'the sulci therebetween are arranged extendflupwafdl'yfrdm the horizontal plane of occlusion at an angle offrorn 20 to 45; and, preferably, at an angle o-f,fr0m1.28' to.'3'5; Whenv'artificialdentures having. correspondingfmejtal m xillary and mandibular bicuspidsand' molars completely 'interdigit-atedare occluded or articulated, the. food therebetween'is cut and sheared into'ver'y fine particles by the points and inclinedsharp gg 2,935,7hi
Patented- May to, 1960 hedral-,cusp-like members with correspondingly deep sulci v therebetween. at the. occlusal surfaces of the. teeth.
' Another object of; this invention is; to provide an artificial denture, having self cleaning, metal posterior teeth provided: with high, sharp polyhedral cusps; arranged on the-.occlusalv surfaces ofthe, bicuspids and molars in a manner such that'each maxillary molar and bicuspid is completely interdigitated with the; corresponding molar and bicuspid when the denture is in its occluded or articulated position.
It is. still another object of this invention to provide an artificialdenturehaving metallic maxillary and mandibular bicuspids and-molarsprovided; withhigh, sharp polyhedral cusps and deep sulci therebetween wherein. the inclined surfacesof the polyhedral cusps extend upwardly fromthe occlusali surfaces. at "an angle of. between. 20 and 45.";,and, preferably,.-at anangle of between 28 and 35.
further object-of thisinyention, is toprovide an artificial denture.- having metallic maxillary and. mandibular bicuspid-s andmolars.provided with polyhedral cusp-like members on theocclusal surfaces, wherein. the apices' of the" cusps and the edgesformed by the intersections of theinclined surfaces thereof are thin andsharp.
A; still, further. object of theiinvention is, to provide metalmaxillary andmandibular bicuspids and molars for a tificial dentures wherein the bicuspids and molars have rowsofpolyhedral cusps adjacentthebuccaland lingual faces of tzhe, teeth and wherein, thelowermost edge of one; inclined surface of each cusp starts at the adjacent buccal or lingualridge andthe inclined surface extends upwardly and inwardly away fromthe buccal or lingual ridgespso that the apices of, the. cusps: a e spaced from the cheek andtongue oftheusera lt is alsov an object of this. invention to. provide an artificial, denture having metalmaxillary andtmandibular bicuspids and, molarssecuredin plates of syntheticresine ous, vulcanized rubber or similar, dental base molding materials and a coating of porcelain or an; acrylic resin on, thebuccal and. lingual surfaces. of the metallic. teeth toreducethe transmission of heatfrom the teeth to the cheeks, of theuser; and, especially, to enhance the appearanee ofjthe, teeth.
The foregoing and other objects are. attained by this invention, the p-referredembodiments of. which are taught in thev following descript-ion. andv illustrated in the accompanying drawings. wherein:
Figure l is. an occlus'al surface View of the maxillary and, mandibular portions of an artificial dentureincluding mjetallic bicuspids and molars constructed in accordance with the principles of this invention;
EigureLZ is a. perspective view of the posterior portions of one side of" the. maxillary and. mandibular, dentures from the'buccal side with'the' dentures in occlusive relationship; I v
Figure 3 isanl enlarged fragmentary perspective view of the metal bicuspid and molar teeth in the mandibular denture; v
Eigure 4"is. anenlarged. fragmentary perspective view Ofthe metallic bicuspid and'molar teeth in the mandibular denture showing moreof the occlusal surface and depicting the arrangement of the cusps and'su'lci in the occlusal surface in detail;
and mandibular portions of an artificial denture including a modification of the metallic bicuspids and molars constructed in accordance with this invention;
Figure 6 is a perspective view of the posterior portions of one side of the maxillary and mandibular dentures shown in Figure 5, from the buccal side with the dentures in occlusive relationship;
Figure 7 is an enlarged fragmentary perspective view of the metal bicuspid and molar teeth in the mandibular denture shown in Figure and Figure 8 is an enlarged fragmentary perspective view of the metallic bicuspid and molar teeth in the mandibular denture shown in Figure 5 showing more of the occlusal surface and depicting the arrangement of the cusps and sulci in the occlusal surface in detail.
Referring to the drawings, the artificial denture comprising this invention is shown in Figure 1 as being composed of a synthetic resinous or other dental molding material upper plate 1 and a lower or mandibular plate 2 formed of a synthetic resinous material. The synthetic resins commonly used in the dental prosthetic field, such as, for example, the well known acrylic dental molding resins may be used in constructing the plates 1 and Z. The lower plate 2 has two molar teeth 3-3 and two bicuspids 4 4 set in the posterior regions of each side of the plate. The molar and bicuspid teeth 3-3 and 4--4 are composed of metal and may be formed by casting any of the metals of extreme hardness which are non-ferrous, non-corrosive, non-magnetic, stainless and capable of being given a high polish that are commonly used in the dental art. It is preferred to employ metals such as cobalt-chromium alloys containing 90% of cobalt and chromium. One such alloy sold under the trade name Vitallium is very desirable. This alloy has the following properties: tensile 100,000-200,000 p.s.i., yield 63,000-67,000 p.s.i., Rockwell hardness 024-38, elongation 2-6% and a modulus of elasticity in tension 30,000,- 000. Another metal alloy suitable for the purposes of this invention is sold under the trade name Duralieum which has properties comparable to Vitallium." Corresponding pairs of molar teeth 5-'5 and bicuspid teeth 6-6 are secured in the upper plate. The maxillary molar and bicuspid teeth 55 and 66 are similarly formed of a metal such as described above.
The novel feature of this invention resides in the structural features of the maxillary posterior teeth 55 and 6-6 and the mandibulary posterior teeth 3-3 and 44 at their occlusal surfaces. The molars 3-3 are provided with a plurality of polyhedral cusps, preferably three adjacent the buccal side thereof and three adjacent the lingual side of the tooth. In the form of this invention shown in Figures 1-4, inclusive, the novel cusp elements employed are shown as being in tetrahedral form. These tetrahedrally-shaped cusps are tall and each cusp 7 has a sharply pointed apex. There are three inclined fiat surfaces on each cusp 7. One inclined surface 8 of each cusp in the row thereof adjacent the buccal surface of the tooth extends upwardly and inwardly away from the buccal ridge of the tooth. There is a corresponding inclined surface 9 on each cusp 7 which is adjacent the lingual side of the tooth and this inclined surface likewise extends upwardly from and inwardly away from the lingual ridge of the tooth. In the foregoing manner the apices of the cusps 7 are spaced inwardly from the buccal and lingual surfaces of the tooth which prevents the sharp points of the cusps 7 from injuring the cheek andthe tongue of the user. Each cusp 7 has two inclined surfaces 10 that extend from the apex of the cusp downwardly to the base of the cusp; and, by spacing the cusps 7 from one another deep grooves or sulci 11 are provided in the occlusal surface of each molar tooth 3-3. The sulci 11 are interconnected and each sulci extends in a lateral or in an anterior or posterior direction to a side of the tooth as is apparent from Figure 4.
In order to obtain an eflicient cutting and grinding action with the teeth it is essential that the tetrahedral cusps be relatively high and have permanently sharp edged occlusal ridges. The inclined surfaces 8, 9, and 10 of each cusp 7 intersect to form thin sharp cutting ridges 12. The height of the cusps necessary to obtain an efiicient cutting and grinding of food is provided by maintaining an angle of inclination of the inclined surfaces 7 8, 9, and 10 with respect to the horizontal plane of occluthe tooth is not substantially increased thereby.
The bicuspid teeth 4 4 in the lower plate are provided with two tetrahedral cusps 13 which are the same in construction and arrangement as the tetrahedral cusps 7. Thus, the cusps 13 have sharp points and each has an inclined surface 14 which extends upwardly from and inwardly away from the buccal or lingual ridge of the tooth adjacent thereto. The cusps 13 also have inclined surfaces 15 which define deep sulci extending to the mesial and distal sides of the tooth. The angle of inclination of the inclined surfaces 14 and 15 of the cusps 13 is between 20 and 45 but an angle of inclination in the range of from 28 to 35 is preferred.
The upper or maxillary plate 1 is constructed in a manner such that the molar teeth 55 and the bicuspid teeth 6-6 are each vertically aligned with respective molar teeth 3-3 and bicuspid teeth 44 in the lower plate. The maxillary molar teeth 5-'-5 are constructed in the identical manner as the mandibular molars 3-'3 except for the fact that the tetrahedral cups 16 are offset with respect to the cusps 7. This arrangement permits perfect interdigitation of the cusps 7 and 16 when the artificial denture is occluded as is shown in Figure 2. The position of the inclined surfaces of the cusps. 16 and the angle of inclination thereof with respect to the horizontal plane of occlusion are identical to those of the cusps 7 so that the cusps 7 and 16 mesh perfectly. The bicuspids 66 of the upper denture each have a pair of tetrahedral cusps 17 which are identical in structure with the cusps 13 of bicuspids 44 and are likewise offset with respect to the latter so that a perfect bite may be obtained.
It will be apparent from the foregoing description that the dentures 1 and 2, when subjected to normal usage are capable of both lateral and anterior and posterior excursion or movement. The sharp points or apices of the cusps 7, 13, 16, and 17 will penetrate foodwith ease under the pressures normally exerted in the mouth.
When the dentures are moved toward an occluded position in either a lateral or an anterior-posterior direction the sharp inclined ridges of each cusp formed by the intersection of the several inclined surfaces thereof, etficiently cut the food. In addition, the cusps 16 are moved into an interdigital relationship between the cusps 7 and thus mash the out food. The latter is due to the action resulting from the movement of the tetrahedral cusp 16 into a complementary space between a pair of cusps 7-7; and, as the wedging inclined surfaces approach, high pressures are brought to bear upon the food particles therebetween. As this movement continues, and the upper and lower dentures approach an occluded position, the food is expressed laterally and in mesial-distal directions through the deep sulci from the teeth.
. A modification of the previously described embodiment of this invention is shown in Figures 5 to 8, inclusive. Theunderlying theory and operation of this modified form of the invention is the same as that ofthe embodiment thereof shown in Figures 1 to 4', inclusive and the principal structural variation between the two embodiments of the invention is that, in the form shown in Figures 5-8, inclusive, the occlusal surfaces of the teeth are provided with serrations which are cusp-like pentahedral elements. In Figure 5 there is shown a lower plate 18 having secured therein a pair of molars 19-19 and a ass-sear pair oflbicuspid's 20-20" in theposteribnregion on eachside oftlie plate. TheL-pl'ate 1'8. stormed? ofasynflietic resin such as an acrylic melding resin or other suitable dental moldingmateria-lr and the. molars, 19. and the bicuspids are formedof a suitable. metal suchas those previously mentioned: Referring to Figure 5; it will be seen that the:maxil1ar.ymolars. 19-1-9r haveaserrated-i occlusal surfaces which. provide saw-tooth liko-points which are obtained by providing a plurality of rows of pentahedral cusp-like elements 21. One such row of elements 21 extends in a mesial-distal direction adjacent the lingual side of each molar 19'and a second row extends in the same direction adjacent the buccal side of the tooth. Intermediate these two rows of cusplike elements there is a third row of such elements extending in the same mesialdistal direction. The elements 21 in each such row are aligned with the adjacent elements 21 in adjacent rows thereof to provide a plurality of rows extending laterally between the buccal and lingual sides of the molar 19. The cusp-like elements 21' in the rows adjacent the buccal and lingual surfaces of the molar 19 each have an inclined surface 22 which extends upwardly from and inwardly away from the adjacent buccal or lingual ridge of the tooth so that the apex of each element 21 in the outer rows will not injure the cheek and tongue of the user.
and lower plat'es'24 and 1'8 are closed in centric reia ti'on. The maxillaryv and mandibular molars -25 and'119-19 operatein the same manner that the molars 3-3- and 5-5 shown' in Figures 1 4; inclusive, operate. The principalvalue of the modified form of molarsshown in Figures 5 to 8, inclusive, is that teeth of thisfOr-m are more suitable 1hr use incases= having a condition known asashort or closedlbitez The metal teeth, and especially the bicuspid teeth shown in Figures l-8, inclusive, may be exposed to view during use. 'In order to enhance the appearance thereof, a facing S of porcelain or an acrylic resin on the buccal surfaces of the bicuspids may be used.
The posterior metallic teeth employed in this invention constitute a distinct departure in structure and theory from those heretofore employed. It has been recognized that the efiiciency of a denture depends upon the structure of the posterior teeth used therewith and some attempts have been made to use posterior teeth having pyramidal cusps. However, in the other tooth structures heretofore employed the cusps has been low and the angles of inclination of the inclined surfaces whether In the lower plate 20 it is preferred to employ three rows of four elements 21, thus: providing a total of twelve pentahedral elements 21. The cusp-like elements 21 are spaced from one another at the bases thereof and the inclined surfaces 23 thereofprovide' channels or deep grooves which are sulci-like and extend both laterally and in anterior and posterior directions to the sides of the tooth. The angle of inclination of the inclined surfaces 22 and 23 of the elements 21 is between 28 and about 45; and preferably is about 45 with respect to the horizontal plane of occlusion. The bicuspids 20-21 shown in Figures 5-8 do not difier in structure from the bicuspids 4-4 and 6-6 shown in Figures lto 4 of the drawings; but, if desired, may have the occlusal surfaces thereof serrated in the same manner .as are the surfaces of the molars 19-19, but a proportionately smaller number of cusp-like elements are formed on the occlusal surface of such bicuspids.
The upper plate 24 which is also formed of a suitable dental molding material has two maxillary molars 25-25 secured therein on eachside of the plate in the posterior regions thereof which are alignedwith the mandibular molars 19-19 in the lower plate 18. Two bicuspids 26-26 are also secured in each side of the upper plate 24 and are also aligned with the bicuspids 29-20 in the lower plate. The bicuspids 26-26 are shown as being identical with the bicuspids 6-6 shown in Figures 1 to 4, inclusive, but these may have serrated occlusal surfaces as described as being useful in the bicuspids 20-20. The maxillary molars 26-26 which are also formed of a suitable metal such as, for example, Duralieum or Vitallium, as previously described and are provided with a plurality of pentahedral cusp-like elements 27 having sharp pointed apices and inclined flat side surfaces 28 and 29. The inclined surfaces 28 on the outer rows of elements 27 are, like the cusp-like elements 21 on the mandibular molars 19, inclined upwardly from and inwardly from the buccal and lingual ridges adjacent thereto so that the apices of the elements 27 in these rows are spaced inwardly from these side surfaces of the teeth. The cusp-like elements 27 in the upper plate are offset with respect to the elements 21 in the corresponding aligned lower molars 19-19. The offsetting of the elements 27 and 21 in the upper and lower molars, respectively, permits such cusp-like elements to interengage in an interdigital relationship when the upper and 7 lower plates 24 and 18 are occluded. In addition, the
use of the same angles of inclination of the inclined surfaces of the cusps 27 and 21, insures a perfect meshing therebetween when these are interdigitated and the upper fiat or arcuate, have been correspondingly low; usually of the order of from 5 to 10 at the most. Cusp or cusp-like members of such a type are, primarily, capable only of grinding food and any cutting action therewith is negligible. Furthermore, posterior teeth have not, heretofore, been arranged so as to provide for complete interdigitation between corresponding upper and lower molars so as to provide complete contact between the interdigitated surfaces of the cusp or cusp-like elements. The molars and bicuspids of this invention are complete ly interdigitated when occluded and the steep inclined surfaces thereof which provide sharp points at the cusp apex and thin sharp edges not only grind but out food rapidly. The high, sharp pointed cusps with very thin edged ridges arranged to provide deep sulci cooperate to render artificial dentures more efficient in masticating food than has been possible heretofore. Whereas the efficiency of mastication with artificial dentures heretofore used has been about 15 percent, basedon the efiiciency of natural teeth, the efficiency of dentures constructed according to this invention is about 50 percent, based on the efiiciency of natural teeth.
1. A dental prosthesis comprising upper and lower dentures having upper and lower metal molar and bicuspid teeth each having a central vertically disposed longitudinal axis, each of said upper molar and bicuspid teeth having its central vertically disposed longitudinal axis fully aligned with the central vertically disposed longitudinal axis of each corresponding lower molar and bicuspid tooth when said upper and lower dentures are in a normal occluded relation to' provide full contact between the entire area of the opposing surfaces of.
sion in the range of from 28 to about 45 the apices of the cusps of each upper molar and bicuspid tooth being offset with respect to the apices of the cusps of the corresponding opposing lower molar and bicuspid teeth to provide complete interdigitation between the apices of each aligned pair of teeth of corresponding upper and lower molar and bicuspid teeth when said upper and lower dentures are in a normal occluded relation.
2. A dental prosthesis as set forth in claim 1 wherein said upper and lower molar and bicuspid teeth polyhedral .7 8 cusp members are tetrahedral and said inclined surcusp members arepentahedral and said inclined surfaces faces have an angle of inclination with respect to the have an angle of inclination with respect to the horizontal horizontal planefof occlusion of between 28 and 35. P t- 9 06911181011. et een 28 and 35 3. A dental prosthesis as set forth in claim 1 wherein said upper and lower bicuspid teeth have a non-metallic 5 References Cited m the file of this Patent facing onv the buccal surfaces thereof. UNITED STATES PATENTS 4. ,A dental prosthesis as set forth in claim 1 wherein 2,115,116 McGrane Apr. 26, 1938 said upper and lower molar and bicuspid teeth polyhedral 2,375,509 Wiechert May 8, 1945