US2521599A

US2521599A - Articulator

Info

Publication number: US2521599A
Application number: US558920A
Authority: US
Inventors: Neil Ewell
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-10-16
Filing date: 1944-10-16
Publication date: 1950-09-05
Anticipated expiration: 1967-09-05

Description

Sept. 5, 1950 E. NE1L 2,521,599

IN VEN TOR.

. 206% Nal,

www lgllu ra/uu Sept. 5,1950 E. NE1L 2,521,599

ARTICULATOR Filed oct. 1e, 1944 s sheets-sheet 2 Sept. 5, 1950 E. NE1L v 2,521,599

v ARTICULATOR 5 Sheets-Sheet 5 Filed Oct. 16, 1944 g l, I? ffm.

IN V EN TOR.

I BY, Emea/VSM,

Patented Sept. 5, 1950 UNITED STATES PATENT OFFICE 13 Claims.

This invention relates to articulators for use in the making and iitting of dentures, both full and partial.

It is generally recognized that the vertical dimension of the lower third of the patients face is the biggest factor in denture esthetics. When the upper and lower ridges of the jaws are separated a distance corresponding to the correct vertical dimension, and the patient is relaxed, the condyle head is in its functional centric position relative to the meniscus and glenoid fossi, which is not its more retruded position, and all of the tissues of the joint of the lower jaw are in their natural and unstrained condition. Due to excessive wear of the teeth, loss of some of the teeth and resultant displacement of others, or loss of all of the teeth, and analogous causes, the original vertical distance between the ridges is reduced, the ridges move closer together, and the condyle moves into a more retruded position, establishing for the patient an acquired centric relation. That not only detracts from a persons appearance, but also results in malocclusion, so that the teeth do not function with maximum eiiiciency in masticating, and the jaw muscles and tissues are displaced and strained, causing discomfort, which in some cases may be serious. The dentists problem is not only to restore the correct vertical dimension of the patients face for esthetic reasons, but also involves accomplishing such restoration in a manner assuring that the condyles will be returned to their original functional centric position while also assuring accurate occlusal contact, in order that the patient may masticate properly and will not be subject to discomfort while masticating or at other times.

The retrusive movement of the lower jaw or mandible diners, and may be appreciably greater or less in the case of one person than in another. That is an important factor, particularly in constructing and tting partial dentures, which must be taken into consideration in opening the bite to restore the proper vertical dimension, in order to attain satisfactory results. My invention is directed to an articulator whereby the dental technician can readily make dentures to provide any desired vertical distance between the ridges, in accordance with the dentists instructions, and in so doing properly takes into account the retrusive movement of the mandible of the patient for whom the denture is being made. More specifically, I provide an articulator in which the member carrying the upper cast is hinged on an axis bearing a denite relation to the alveolar ridge, or the distal surface of the cutting edge of the upper central incisor, and the occlusal plane, and the mounting plate for the lower cast may be adjusted toward and away from the upper cast along an inclined plane such as to impart to the lower cast the proper retrusive movement for the particular case. Further objects and advantages of my invention will appear from the detail description.

In the drawings:

Figure 1 is a plan View of an articulator em' bodying my invention, with casts mounted thereon carrying bite rims;

Figure 2 is a side view of the articulator of Figure 1;

Figure 3 is a sectional view taken substantiallyl on line 3-3 of Figure 1, certain parts being shown in elevation;

Figure 4 is an underneath view of the mounting plate for the lower cast;

Figure 5 is a plan'view of the base of the artculator, with parts broken away and the mounting plate for the lower cast removed;

Figure 6 is an underneath view of the lower mounting plate adjusting ring assembly and assoi ciated parts;

Figure 7 is a plan view of the base of the arinvention. It comprises a base I0 having twol rear'arms Il and a forwardly extending arm I2, which arms are integrally united at their inner ends by a hub portion I3 on the upper face of l which and of arm I2 is secured a base plate Il. y

An upright l5 is mounted in the outer end of each arm I I for adjustment about a vertical axis, for a purpose and by means which form no part of my instant invention and need not be further de` scribed here. Each upright l5 is provided at its upper end with condyle adjusting means I6 which,

as such, constitutes no part of my instant invention and requires no further description here. Adjusting means I1 is also provided at the forward end of arm I2 and, as such, constitutes no l part of .my present invention and, accordingly,`

need not be further described here.

Each of the condyle adjusting means includes a ball I8 which is axially bored for reception 0i a shaft I5 rockably mounted in the two balls il. l

This shaft I9 passes through a sleeve 20 at the rearward end of an upper arm 2| extending forwardly from the shaft in overlying relation to base I0, sleeve 20 being xed to shaft I 9 in any,

suitable manner, conveniently by means oiset screws, one of which is shown at 22. A mounting frame 23, of known construction, is removably secured to arm 2| at the underface thereof, by means of 'a screw 24 rotatably mounted through arm 2i and threading into frame 2l, the

latter being provided at its rearward portion with, a groove 25 extending forwardly from its rear-, ward edge, this groove receiving a stud 26 xed in arm 2| and effective for restraining frame 23 against turning movement. Arm 2| is provided, at its forward end, with a downwardly extending sleeve 21,. this sleeve and the forward end of the arm being bored for reception of a supporting rod 28 slidable therein and secured in adjustment by a set screw 29. At its lower end rod 28 contacts a stop 30 of the adjusting means I1., for restraining arm 2| against downward movement, the upper portion of rod 28 being graduated in millimeters and fractions thereof., at 3|. It will be seen that the forward end of arm 2| may be adjusted at any desired height, within limits, by means of the rod 28 and associated members.

A plate 32 of substantially semi-circular shape is secured upon the plate I4, by means of a bolt 33 passing through hub I3 and base plate I4 and plate 32, and a nut34 screwing on the upper end ofthe bolt. A screw .35, passing through the plates 32 and I4, threads into hub I0 and restrains-plate 32 against turningl movement about the bolt 33. An interiorly threaded collar 36- is secured upon the upper face of lplate 32. and is exteriorly graduated to indicate vertical adjustment in millimeters and fractions thereof, Aas will appear more fully presently. An exteriorly threaded adjusting ring 3'I-screws into collar 32, thisring. being provided with an outwardly projecting .circumferential flange 38, the outer face of which is roughened or knurled, as shown, the upper portion of the ring 31 being reducedin wall thickness to. provide a circular flange 39 projecting upward an appreciable distance above ange 38.. The latter flange is providedV with a depending pointer .40 movable over the scale on the collar 32. pointer, vindicates the vertical adjustment of ring 31 in collar 35,. by threading the ring in-to` or out of the collar as conditions require;

AThe upper face or edge of flange 39 is disposed in .a plane normal .to the axis. of ring 31, that is, in a horizontal plane.

A mounting plate 4I., for a lower cast, seats upon. the upper edge of flange 39 of ring 31.. This plate 4|. is provided witha .plurality of threaded studs .42 secured therein and projecting thereabove to provide anchorage for a cast mounted upon the upper face of plate 4|. At its under face plate .4| is provided with two depending spaced ears 43 fixed thereto in a suitable, manner, as by welding, between which is pivoted a bar 44 carrying, adjacent each end, a .rod 45 .secured atits upper end to. the. bar 44.

Hub I 3 and base plate I4 of base I0 are provided -with two upwardly opening grooves 46 communicating `attheir rearward .ends with opening 41 .through hub I3. These grooves receive two mountinglugs 48 welded or .otherwise suitably secured to plate 32 and projecting rearward beyond opening. 4B therein. The lugsA 48 receive between thema hub 50, which is pivoted between the. lugs, of 'a substantially .U -shaped yoke 5I `extending upward through opening 49; The yoke 5I iSV provided, at each end thereof, with a tubular arm 52, and these arms. slidably receive the rods 45, wh ich ymay be termed retrusion. rods. A recording arm 53 is fixed at its upper end to hub 5U and extends downward therefrom at one face of an angle bracket 54 which is suitably secured, conveniently by means of screws 55, to hub I3 of base I 9. The lower end portion .of arm 53 is formed to provide an indicator point 56 which is movable over a scale '51 on bracket 54, graduated to indicate the angle of inclination of the arms This scale, in cooperation with the- 52` ofyolgei to the horizontal. A 'locking screw 15 i meter.

-., material, in a known manuel'.

58 passes through a slot 59 in arm 53 and through bracket 54, this screw threading into a nut 60 xed to bracket 54 at the face thereof opposite to arm 53.

From what has been said it will be seen that the upper arm 2| of the articulator is ingedly mounted for adjustment about a horizontal axis, and that the forward end vof this arm may be adjusted toward and away from the base I0 by means of the supporting rod 28. It will also be seen that the mounting plate 4I for the lower cast may be adjusted vertically by means of the adjusting ring 3l, and that in the adjustment of this plate with the ringlit moves backward o1' forward relative thereto a distance .determined by the amount of vertical adjustment and by Vthe angle of the yoke 5I to the horizontal, the retrusion rods 45 sliding through the arms 52 of yoke 5I during such adjustment. By proper admore fully presently. As a result of extensive ind 'estigation and the taking of accurate measurements in more than one thousand cases, I have been able to establish cer-tain rules applicable to the construction of dentures, either full or partial, the observance of which is essential to accuracy, and the articulator of my invention is particularly `suitable for practicing such rules. In the average person, the distance from the incisal or cutting edge of the upper central incisor to a line passing laterally .across the distal surfaces of the upper second molar teeth, taken perpendicular to that line, is two inches. In `opening the jaws the ratio between these two points is l to .7; that is, for one millimeter of vertical movement of the lower central incisor the corresponding lower molar moves. vertically .7 of a milli- That ratio has been shown by tests in more than 1000 cases to be the actual relativel movement, and may be accepted as a standard or constant in dealing with natural teeth. In cases where no natural teeth are present, the alveolar ridge is taken as the central anterior point and a point two inches distal from that ridge is taken as the posterior point, the ratio between these two points taken as l to .7 as before.

In describing the use of the articulator of my invention, I will first consider the case of openinf,T the bite for full dentures. The dentist rst takes impressions of the upper and lower jaws, from which he makes casts, and on the casts lie constructs bite rims of wax or other suitable The bite rims. which may be of any height deemed appropriate by the dentist, are then placed in the patients mouth and are trimmed so as to secure accurate occlusal contact between them. Suitable horizontal marks are then placed upon the bite rims at the anterior labial surfaces thereof and the vertical distance between those marks in the Vertical plane of the alveolar ridge is accurately measured and recorded. The casts and the bite rims, together with the vertical measurement referred to and instructions to open the bite a definite amount, are forwarded by the dentist to the dental laboratory technician. The extent to which the bite is to be opened will depend upon circumstances and the dentists judgment. In theory, it is desirable that the original natural vertical dimension be restored, with the oondyles in their original or natural functional centric position. This position may e determined by accurately traced gothic arches,

fession, it being known that the mandible has its greatest freedom of lateral movement or excursion at the correct or original natural vertical dimension, at which the condyles are in their original or natural functional centric position. In general, however, it is not desirable to restore the natural vertical height at one operation, though that may be done in certain cases, and the bite usually is opened to an extent less than that required to restore the original o r natural vertical dimension.

Upon receipt of the casts and the bit rims, together with the vertical measurement and instructions from the dentist as to the extent to which the bite is to be opened, the technician mounts the upper cast upon frame 23 in such manner that, when this frame and the cast are mounted upon arm 2|, the distance from the alveolar ridge to the axis of shaft I9, which is the hinge axis of arm 2|, is 21/2 inches posterior to the center of the gum papilla of the upper alveolar ridge, taken on a line perpendicular to a line extending between two points two inches distal to that ridge. The lower .cast is mounted on plate 4| in proper relation to the upper cast, the casts being so disposed that, with the bite rims thereon, the occlusal plane is horizontal and spaced 1% inches below the hinge axis of arm 2 I. In the case of whole dentures, the arm 53 is locked in such position that the retrusion rods 45 are disposed at an angle of 50 to the horizontal, which has been shown to be the proper angle by my investigations. The casts are so adjusted that, when the bite rims thereof are in accurate occlusal contact, the vertical distance between the maries on the anterior labial surfaces of the rims is the same as the distance between those marks when the rims were in the patients mouth With the casts mounted and accurately positioned in the manner stated, the technician then proceeds to open the bite to the desired extent.

With a 21/2 inch radius of movement of the arm 2|, and the occlusal plane 1%, inches below the hinge axis of varm 2|l the ratio of opening of the articulator at the center of the anterior gum papilla of the alveolar ridge to opening at the point corresponding to the distal cusp of the sec-1 ond molar is 1 to .4. That is to say, for every millimeter of opening at the anterior gum papilla of the alveolar ridge by upward swinging movement of arm 2|, the bite rims will be opened .4 of a, millimeter at points corresponding to the distal cusps of the second molars. Under the conditions stated, the rule for opening the bite is to open one-half the desired distance by moving the lower cast downward, and then open the other half of the desired distance by swinging the arm 2| and the cast carried thereby upward. Referring to Figure 2, I have .shown upper and lower casts 6| and 62, respectively, mounted on frame 23 and on plate 4|, these casts carrying upper and lower bite rims 63 and 54 mounted thereon with the casts adjusted so that the bite rims are in accurate occlusal contact. Assuming thatit is desired to open the bite millimeters, the adjusting ring 31 is screwed into collar 36 a sucient distance to lower the mounting plate 4|, and with it the lower cast 62, 5 millimeters. During this lowering operation the retrusion rods 45 Slide rearward and downward through the tubular arms 52 of yoke 5|, and the mounting plate 4| is thereby moved a slight distance rearward upon the upper face of ange 39 of ring 31, thus imparting to the lower cast 62 proper retrusive movement. That opens the bite 5 millimeters at both the posterior and the anterior areas of the bite rims. The set screw 23 is then loosened and the arm 2| is swung upward about its hinge axis, with rod 28 resting upon the stop 30, a proper distance to move the upper cast 6|, at the gum papilla of the alveolar ridge thereof, upward a vertical distanceof 5 millimeters. In this upward movement of the upper cast, the bite is opened 5 millimeters at the incisal area of the bite rims and is opened .4 of 5 millimeters, or 2 millimeters, at the molar areas of the bite rims. Accordingly, the bite has been opened 10 millimeters at the incisal areas of the bite rims and 'l millimeters at the molar areas thereof, maintaining between such areas the proper natural ratio of 1 to .7, which my investigations have shown to be the proper ratio and to conform to the relative movements of those areas in the average person. After the bite has been opened in the manner stated, the technician mounts artiiicial teeth upon the bite rims so as to give accurate occlusal contact between the teeth, as is well understood in the dental profession, constructing models or patterns from which the ultimate dentures are made in a known manner.

So far I have considered the case of opening the bite for full dentures for persons having mouths of normal or average size. Some persons have exceptionally large mouths, and in such cases the procedure of opening the bite is somewhat different than described above. In opening the bite for persons with exceptionally large mouths, the upper cast is mounted so that the hinge axis of arm 2| isSl/g inches posterior to the alveolar ridge. The ratio of opening of the incisors to opening of the molars, in swinging the upper cast about its hinge axis, then becomes 1 to .5, and the rule for opening the bite is to lower the lower cast 40% of the total distance and raise the upper cast 60% of the total distance about its hinge axis. For example, to open the bite 10 millimeters, the lower 'cast is lowered 4 millimeters, opening both the incisors and the molars 4 millimenters and the upper cast is swung upward 6 millimeters at the incisal area, thus opening the molars a further distance of 6 .5, or 3 millimeters, giving a total opening of 10 millimeters at the incisors and 7 millimenters at the molars, the ratio of opening at the incisors to opening at the molars being 1 to .7, as before.

In the case of full dentures, considered above, the retrusion rods 45 may be considered as xed at an angle of 50o to the horizontal, which angle has been found by me to be appropriate for such cases. While this 50 angle does not take into account variations in retrusion, it has been found to be suitable for all cases of full dentures, any slight inaccuracies as to retrusion being readily accommodated by slight movement of the dentures on the gum tissues and eshly parts which support them, and, for that reason, are of no significance.

When constructing partial dentures, greater precision is required with respect to retrusion than is necessary in the case of full dentures, since movement of the partial dentures to accommodate slight inaccuracies in occlusion is precluded or reduced by the natural teeth present. Accordingly, in the case of partial dentures, the

dentist makes upper and lower casts, and also takes a bite impression of the patients teeth, and turns these casts and the bite impression over to the technician with a record of the vertical distance between the upper and lower gingival margins, bothfwthout the bite impressionin the patients mouth and with the ybite impression inA the patients mouth, the bite impression being 'taken in, wax, impression compound, or other suitable `material then removed from the patients mouth and hardened .as by immersng in cold water and being then accurately replaced within the mouth, the vertical distance between the upper and lower gingival margins at the central incisors being accurately measured after the hardened bite impression has been replaced. The dentist also transmits to the technician instructions with respect to the amount to which the bite is to be opened. Upon receipt of the casts and the bite impression from the dentist, together with the vertical measurements and his instructions with respect to the extent of opening of the bite, the technician mounts the casts upon the articulator in occlusal contact, with the distal surface of the cutting edge of the upper central tooth 21/2 inches anterior to the hinge axis of arm 2l and the occlusal plane 11/4 inches below that axis as before, and with the vertical distance between the gingival margins of the central incisors the same as the vertical distance recorded by the dentist, for example, millimeters. Assuming that the vertical distance recorded by the dentist between the gngival margins at the central incisors is 15 millimeters, with the bite impression in the patients mouth the technician then opens the bite 5 millimeters by lowering the lower cast 21/2 millimeters and raising the upper cast 21/2 millimeters, in the same manner as previously described in connection with whole dentures. Having opened the bite ve millimeters, the technician then places the bite impression between the casts, in accurate cuspal register with the upper cast, and adjusts the lower cast so that it also is in accurate cuspal register with the bite impression. Prior to this adjustment of the lower cast, the locking screw 5% has been released to permit movement of yoke 5I and retrusion rods 45, the angle of the latter to the horizontal being adjusted to suit the particular case inthe adjustment ofthe lower cast, effected by adjustment of the mounting plate 4l. The retrusion rods 45 are thus adjusted at an angle which may be a few degrees more or less than to the horizontal, such angle corresponding to the retrusive movement of the mandible of the particular case. After the proper adjustment of the lower cast has been eiected, the locking screw 58 is tightened, thus locking the retrusion rods 45 at the proper angle for that case. The technician then removes the bite impression and proceeds to open the bite in accordance with the dentists instructions. Assuming that it is desired to open the bite 3 millimeters, it will be seen that in adjusting the casts to receive the bite impression the bite has been opened a distance of 5 millimeters. Accordingly in order to open the bite 3 millimeters, that distance is reduced 2 millimeters, by raising the lower cast l millimeter and swinging the upper cast downward about its hinge axis a distance of l millimeter at the central incisors. The bite has then been opened to the desired extent of 3 millimeters. In thus opening the bite the proper retrusive movement is imparted to the lower cast since, as noted, the retrusion rods 25 have been set at the proper angle for the particular case. After the bite has been opened to the proper extent, the technician may now follow those conventional laboratory procedures that are commonly used in the construction of a partial denture. whether it be cast of metal, synthetic resin, or any other known sultable material. The partial dentures are .delivered to the dentist who fits them in the patients mouth, and .the natural teeth are then built up by overlays and/or jacket crowns, as

required, to give accurate occlusion for the opened' bite. What has been said so far with respect to partial dentures, applies to persons having mouths of normal or average size. In the case of persons having exceptionally large mouths, the upper cast is hinged on an axis 31/2 inches posterior to the distal surface of the cutting edge of the central incisor and the upper cast is adjusted 60% of the desired distance, the lower cast being adjusted 40% of the desired distance, as above explained with reference to full dentures.

Literally thousands of bite registrations and impressions for full and partial dentures are sent in daily by dentists to commercial dental laboratoi-ies. In many of these cases correct and adequate instructions are sent by the dentists, to open or close the bite. In many other cases, no instructions are sent, or the instructions are incorrect or inadequate. The technician knows, from established data and published records of dental researches well as text books on dental anatomy, that the vertical measurement or inter-ridge distance for the average person should be a denite amount, approximately 21 mm. Accordingly, 'in cases where the technician receives no instructions from the dentist, or receives inadequate instructions, he may proceed in the setting and articulation of the teeth, by the use of my articulator in the manner above set forth, with the assurance that he will attain a perfect intercuspal relation. That is of importance as effecting, in such cases, a substantial saving in valuable chair time of the dentist, which is desirable for obvious reasons.

It will be understood by those familiar with dental technique that changes in construction and arrangement-l of parts of the articulator of my invention may be resorted to without departing from thel field and scope or my invention, and I intend to include all such variations, as fall within the scope of the appended claims, in this application in which the preferred form only ot my invention has been disclosed.

I claim:

l. In an articulator of the character described, a mounting arm pivoted at its rearward end on a transverse horizontal axis, means for adjusting said arm about its pivot axis, a mounting plate underlying said arm, means for adjusting said plate vertically toward and away from said arm, xed 'inclined guide members, and retrusion members pivoted to said plate telescoping said guide members cooperating therewith for imparting forward and rearward movement to said plate responsive to raising and lowering thereof.

2. In an articulator of the character described, a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at, its rearward end, an adjusting member mounted on said base for vertical adjustment toward and away from said arm, a mounting plate seating on said member for vertical adjustment therewith and free therefrom for relative translatory movement thereon, guid members on said base underlying said plate xed at an inclination extending in a direction upward and forward of said base, and retrusion members pivoted at their upper ends to said plate telescoping said guide members.

3. In an articulator of the character described, a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at its rearward end, a mounting plate on said base, means for adjusting said plate vertically toward and away from said arm, a guide member mounted on said base inclined lengthwise thereof and adjustable to vary its inclination to said base, and a retrusion member pivoted to said plate telescoping said guide member cooperating therewith for imparting forward and rearward translatory movement to said plate responsive to raising and lowering thereof.

4. In an articulator or" the character described, a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at its rearward end, a mounting plate on said base, means for adjusting said plate vertically toward and away from said a guide member mounted on said base underlying said plate inclined upward and forward of said base and adjustable to vary its inclination to said base, and a retrusion member pivoted at its upper end to said plate telesccping said guide member.

5. In an articulator oi the character described, a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at its rearward end, a mounting plate on said base, means for adjusting said plate vertically toward and away from said arm, a yoke underlying said plate pivoted on said base for adjustment about an axis parallel with the pivot axis of said arm and inclined upward and forward of said base, means for locking said yoke in adjustment, and a retrusion member pivoted at its upper end to said plate telescoping said yoke.

e', In an articulator of the character described a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at its rearward end, a collar fixed to said base, a ring having threaded engagement with said collar for vertical adjustment thereon toward and away from said arm, a mounting plate seating on and free from said ring, a yoke underlying said plate pivoted on said base for adjustment about an axis parallel with the pivot axis of said arm and inclined upward and forward of said base, means for lockingV said yoke in adjustment, and a retrusion member pivoted at its upper end to said plate telescoping said yoke.

7. In an articulator of the character described, a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at its rearward end, a plate fixed to said base, an interiorly threaded collar fixed to said plate, an exteriorly threaded ring screwing into said collar for vertical adjustment toward and away :from said arm, a mounting plate seating on and free from said ring, a yoke underlying said mounting plate pivoted on said first plate for adjustment about an axis parallel with the pivot axis of said arm and inclined upward and forward of said base, means for locking said yoke in adjustment, and a retrusion member pivoted at its upper end to said mounting plate telescoping said yoke.

8. In an articulator of the character described, a base, a mounting arm overlying said base adjustable about a transverse horizontal axis at its rearward end, a plate iixed to said base, an interiorly threaded collar fixed to said plate, an exteriorly threaded ring screwing into said collar for vertical adjustment toward and away from said arm, a mounting plate seating on and free from said ring, a yoke underlying said mounting plate pivoted on said nrst plate for adjustment about an axis parallel with the pivot of said arm, said yoke having forwardly extending arms inclined upward and forward of said base and a rearwardly extending arm, means for locking the latter arm to said base, and a retrusion member pivoted at its upper end to said mounting plate telescoping the forwardly extending arms of said yoke.

9. In an articulator of the character described, in combination, an upper mounting arm pivoted on a generally horizontal axis and adapted to support an upper cast, means for adjusting said arm about its pivot axis, guide means arranged at an angle to the horizontal, and a lower mounting member' underlying said upper mounting arm and being movably directed by said guide means and movable at an angle corresponding to the angle at which the guide means is arranged to the horizontal, whereby said lower mounting member has both vertical and horizontal components of displacement when moved in guided cooperation with said guide means, said lower mounting member being adapted to support a lower cast.

1G. An articulator according to claim 9 wherein the guide means comprises at least one rst guide member having pivotal support and arranged at an angle to the horizontal and at least one second guide member having pivotal connection with the lower mounting member and having telescopic movement relative to said rst guide member at an angle corresponding to the angle at which said first guide member is disposed.

i1. An ar ticulator according to claim 9 wherein the lower mounting member is carried by screw means operable to transmit the angular movement to said lower mounting member.

12. In an articulator of the character described, in combination, an upper mounting arm pivoted on a.. generally horizontal axis and adapted to sup-port an upper cast, means for adjusting said arm about its pivot axis, a lower mounting member underlying said arm and adapted to support a lower cast, guide means for said lower mounting member, said guide means being disposed at an angle to the horizontal, and means for moving said lower mounting member through said guide means at an angle corresponding to the angle at which said guide means is disposed to the horizontal whereby to impart both vertical and horizontal components of displacement to said lower mounting member.

13. In an articulator of the character described, in combination, guide means arranged at an angle to the horizontal, and a lower mounting member being movably directed by said guide means and movable at an angle corresponding to the angle at which the guide means is arranged to the horizontal whereby said lower mounting member has both vertical and horizontal components of displacement when moved in guided cooperation with said guide means, said lower mounting member being adapted to support a lower cast.

ENVELL NEIL.

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

UNITED STATES PATENTS Number Name Date 1,812,381 Streker June 30, 1931 1,815,956 Ralph July 28, 1931 2,200,058 Chott May '7, 1940 2,235,524 Leutz Mar. 18, 1941 gsge-Gl-