US3350782A

US3350782A - Dental apparatus and method

Info

Publication number: US3350782A
Application number: US301039A
Authority: US
Inventors: Niles F Guichet
Original assignee: Niles F Guichet
Current assignee: TDY Industries LLC
Priority date: 1963-08-09
Filing date: 1963-08-09
Publication date: 1967-11-07
Anticipated expiration: 1984-11-07

Description

N. F. GUICHET DENTAL APPARATUS AND METHOD Nov. 7, 1967 3 Sheets-Sheet 1 Filed Aug. 9, 1963 INVENTOR. M/e; A Gum/wt Y B 4&2...

ATTORNEY Filed Aug. 9, 1963 Nov. 7, 1967 GU|CHET 3,350,782

DENTAL APPARATUS AND METHOD 3 Sheets$heet 2 INVENT OR. All/e5 G-urc A9:

zQ Q/JI/W ATTORNEY N 1967 N. F. GUICHET 3,350,782

DENTAL APPARATUS AND METHOD Filed Aug. 9, 1963 3 Sheets-Sheet 3 INVENTOR. IVI/ S F gum/ref ATTORNEY United States Patent 3,350,782 DENTAL APPARATUS AND METHOD Niles F. Guichet, 320 Olympia Place, Anaheim, Calif. 92805 Filed Aug. 9, 1963, Ser. No. 301,039 Claims. (Cl. 3232) This invention relates to a method and improved apparatus for reconstructive dentistry and, in particular, relates to improvements in a dental articulator and face bow and to a method for their use.

A major disadvantage of most articulators is the absence of means to permit an immediate side shift (immediate Bennet shift) upon lateral excursion. These articulators only permit a gradual side shift (progressive side shift or timed Bennet shift) when combined with rotation of the jaw model about the hinge axis or with a lateral rotation about the left or right condyle.

Many patients, however, exhibit an immediate Bennet or side shift in their initial movement to right or left of centric. While the degree of this shift is often very slight, a study of many pantographic writings revealed that it occurs in most patients. The fact that the mandible makes an immediate side shift greatly influences tooth anatomy as any case built on an instrument which fails to provide an immediate side shift will have immediat interferences on lateral excursive mandibular movements when the case is seated in the mouth. The interference is particularly significant when the case is Waxed in the commonly advocated cusp-fossa relationship. The failure to reproduce the immediate side shift on the articulator necessitates extensive custom fitting in the patients mouth.

While a few articulators have been designed to faithfully reproduce the exact tracings of jaw movement, considerable time and effort must be expended in custom grinding mechanical stops and guides for these instruments. As a result, these instruments have generally been used for experimental studies and have not found ready acceptance by the practitioner.

Another disadvantage of many articulators is that there is no facile means for accurately mounting the face bow on the instrument when transferring between the patient and instrument. Additionally, subsequent remounts require the reassembling of the face bow and bite fork to tattooed reference points on the face of the patient.

It is an object of this invention to provide an articulator having means that permit a precise and measured side shift of the upper frame member.

It is a further object of this invention to provide means to lock the face bow into position of the hinge axis of the articulator, positively, accurately and more efliciently than any means presently available without the need of mounting stand, jack screws and fine adjustments.

It is also an object of this invention to provide a means for making subsequent transfers of the working cast to the instrument after the initial registrations without reorienting the face bow on the patient, thereby eliminating the objectionable tattoo marking of the patient.

It is also a further object of this invention to provide the auxiliary apparatus and method to utilize an anterior writing and checkbite pin system of recording jaw movements to its full advantage.

Other and related objects will be apparent from the following description of the invention.

Referring now to the figures:

FIGURE 1 illustrates a suitable tracing device and checkbite system and the improved face bow of my invention;

FIGURE 2 illustrates the lower frame of a dental articulator with the improved face bow mounting means of my invention;

FIGURE 3 illustrates the upper frame member of the articulator with the Bennet stops of my invention;

FIGURE 4 illustrates the upper frame member of an articulator also having Bennet stops according to my invention; and

FIGURE 5 illustrates how Bennet stops of my invention can be applied to a conventional articulator, specifically, that described in U.S. Patent 2,816,360.

Referring now to FIGURE 1, there is illustrated a Thompson tracing device and checkbite recording means that can be used with the improved face bow and mounting means of my invention. The tracing device employs writing styli such as 40 to record anterior gothic arch tracings on anterior pads 15a and 18a and the checkbite pins such as 45 to record centric, protrusive and right and left lateral registrations in a wax coating on surfaces 15b and 18b. The apparatus includes eight pins such as 45 that are labelled for registration of right and left centric, right and left protrusive, right and left left lateral and right and left right lateral positions. The right centric pin i shown with label CR in FIGURE 1.

Although my invention is illustrated in regard to an anterior tracing and checkbite pin system, it will be apparent from the following description that various commercially available pantographs employing vertical and horizontal posterior slide tracings and checkbite systems can also be used.

My preferred method, however, utilizes the anterior tracing and checkbite system illustrated. This device comprises a lower face bow and an upper crossbar with tracing arms. The face bow is formed by lower tubular crossbar 1 and rigid side rods 2 and 3. The side rods are attached to crossbar 1 by suitable clamping means such as

blocks

4 and 5 having two traverse bores that receiv an end of the side rod and an end of the crossbar, respectively. One side of the block is slit along the axis of each bore; see 4a and 4b; to permit the block to be compressed and thereby clamp the rods. An adjustment screw 6 is furnished that engages a threaded tap below slit 411 so that block 4 can be compressed into a clamping relationship on crossbar 1 and side rod 2. A similar screw 7 is provided in clamp 5.

At the ends of side rods 2 and 3,

opposite clamps

4 and 5, are positioned similarly constructed block clamps 8 and 9, respectively. These clamps have adjustment screws 10 and 11 to secure centering pins 12 and 13 which are used to orient to the hinge axis reference points and to mount the tracing device in the articulator as hereafter described.

Disposed along lower rod 1 are: the right anterior tracing pad 15, an axis-orbital plane support rod clamp 16, a mandibular clutch mounting clamp 17, the left anterior tracing pad 18 and a vise grip 19. Clamp 17 has a recess that engages a pin or key permanently attached to crossbar 1 at its midpoint and a screw 20 is used to secure clamp 17 to the crossbar. Mandibular clutch 23 supports the conventional intaglio impression of the lower teeth of the patient case in resin 24.

The upper frame of the tracing device comprises an upper crossbar 30 and maxillary clutch mounting clamp 31, similar in construction to clamp 17, attached thereto. Tracing arms 36 and 37 are positioned on crossbar 30 and are generally centered vertically above the right and left anterior tracing pads 15a and 18a respectively.

Screws

28 and 29 are used to secure arms 36 and 37 to rod 30. Although not shown, a similar construction is used to secure the

anterior tracing pads

15 and 18 to lower crossbar 1.

Tracing arms 36 and 37 have

sleeves

38 and 39 to receive tracing styli such as 40 shown in the right tracing arm 36 and

screws

41 and 42 to clamp the styli in the arms. Each of the tracing arms also has a second sleeve 43 and 44 to receive checkbite pins such as 45 shown in the right tracing arm 36. Screws 46 and 47 are provided in each tracing arm opposite supports 43 and 44 to tightly secure pins such as 45 to the arm. As illustrated, pin 45 has a clamp 49 adjustably attached thereto to register the vertical position of the pin within the tracing arm.

A vise grip is illustrated on the crossbar 1 and comprises a bar having traverse grooves or a suitably roughened surface that is clamped to crossbar 1 by member 19 and

screws

26 and 27 which engage threaded taps in member 25. These conventional vise grips are not used for recording jaw movements, but are used to temporarily lock crossbar 1 to crossbar in mounting the casts in the articulator, as hereafter described.

Referring now to FIGURE 2, there is illustrated the lower frame of a conventional articulator to which my improved rigid face bow and mounting technique can be applied. This articulator comprises a base 50 with support legs 51 that rest on a working surface. A conventional incisal guide is shown to comprise wings 52 and 53 pivotably mounted on lip 54. The incisal guide is mounted on base 55 which can rotate within the concave groove shown in the base. Adjustment wheel 56 clamps the incisal guide in the desired position.

A slotted plate 60, for mounting the lower east, is removably attached to base 50. At the back of the articulator base are supports 61 and 62 for crossbar 63. The opposite ends of crossbar 63 have longitudinal grooves 64 and 65 that furnish supports within which the condyle support arms 66 and 67 are slidably mounted. Adjustment wheels such as 68 are furnished to lock the support arms at the desired position as indicated on a calibrated scale marked on the back of crossbar 63.

Crossbar 63 is cut at its mid-point with recess 59 that forms a seat for a centric keying means shown removed from and behind the articulator in FIGURE 2. The centric keying means is used to center the upper frame member of the articulator in its proper medio-lateral relationship to the lower member when the Bennet stops of my invention are set to permit an immediate side shift or are otherwise disengaged. This keying means comprises a base 93 that supports knife blade 94 pivotably mounted on shaft 95 between uprights 96. A spring such as 97 can be used to bias knife blade 94 forward to bear against groove 121 of the upper frame member shown in FIGURE 3. The lower end of blade 94 is preferably rounded to permit the blade to be tipped backwards out of engagement and held there by spring 97.

The condyle tracks 91 and 92 are rotatably mounted on condyle supports arms by a shaft such as 73 that extends through a vertical bore in support arm 67. The lower end of the shaft is threaded to receive lock wheel 74. The upper end of these shafts are attached to journal rings 69 and 72 that serve as mounts for condyle supports 71 and 72. At the base of the journal rings is a calibration mark to indicate the degrees of rotation of the journal rings about their shafts, such as 73, in the support arms. The readings on these scales register the progressive side shift or timed Bennet as hereafter described.

Rectangular notches are cut in each of said condyle supports 71 and 72 and condyle tracks 91 and 92 are provided in these notches.

Grooves

75 and 76 are provided in the journal rings through which set screws 77 and 78 extend. The set screws seat in threaded taps in supports 71 and 72 to lock these condyle supports at the desired angle of inclination for the condyle tracks. A scale is provided on each of the journal rings with a calibration mark on each of the condyle supports to indicate the angle of inclination of the condyle tracks from the horizontal. Set screws 88 and 89 are used to urge a cam stop into tracks 91 and 92 to thereby lock balls 82 and 83 in centric position, when desired. Set screws 86 and 87 also urge cam stops in the condyle tracks to prevent accidental discharge of the balls from the tracks.

As previously mentioned, one feature of my invention comprises a telescoping mounting axis having mounting recesses such as 85 for engagement by centering pins 12 and 13 of the rigid face bow. The mounting axis comprises a shaft 80 that telescopes into sleeve 81. Bearing balls 82 and 83 are mounted on sleeve 81 and shaft 80, respectively, and the end of said shaft and sleeve can comprise shanks such as 84 that have countersunk recesses such as 85 on the centerline of the mounting axis to receive centering pins 12 and 13. Shaft 80 can be calibrated and used to set the proper distance between the vertical rotation centers. The proper setting is determined by using the mounting axis to measure the distance between the points of centering pins 12 and 13 when the face bow is removed from the patient. Preferably, shank 84 is sufficiently long to space the vertical rotation centers of the insturment a distance from the points of the centering pins that corresponds to the average inset of these centers from the side of the patients face.

A second element employed in my improved face bow mounting technique comprises the axis-orbital plane support rod that preferably is calibrated as shown and is secured to crossbar 1 of the face bow with clamp 16. The length of this support rod is made equal to the vertical distance from the center of countersunk recesses 85 to the working surface that supports the articulator so that a horizontal plane is thereby established through the hinge axis and the upper end of the support rod. A small diameter pin 91 extends from the upper end of support rod 90 to aid in supporting an axis-orbital plane indicator such as the Ney Axis orbital plane indicator, not shown.

Referring now to FIGURE 3, there is illustrated the upper member of the articulator adapted to fit into con-- dyle tracks 73 and 74 of the articulator base when the: mounting axis is removed and used therein to mount the maxillary cast. This member comprises an arm with an integral sleeve 101 through which extends shaft 102. Slidably mounted on shaft 102 are the Bennet shift stops 103 and 104 of my invention, hereafter described in detail, and bearing balls 105 and 106.

A slotted plate 107 for mounting the upper cast is secured to arm 100 by wheel 108. A conventional incisal pin 108 is secured to the end of arm 100 by adjustment wheel 109.

The Bennet shift stops of my invention shown at 103 and 104 comprise calibrated means for precisely adjusting the articulator to permit a predetermined or controlled immediate side shift of the upper articulator member and cast to thereby duplicate patient jaw movements. The construction of the particular Bennet shift stop illustrated in FIGURE 3 can be seen by the exploded view of the right stop 103. This stop comprises a first element, wheel 110, slidably mounted on shaft 102 with a lock means, screw 111, to firmly secure wheel 110 to shaft 102 at a desired lateral position. A second element, wheel 113, is associated with wheel 110 in a laterally adjustable relationship thereto; as shown, wheel 113 is mounted onto the threaded neck 112 that extends from wheel 110. A restraining means such as spring is used to restrain wheel 113 against unintentional movement. A scale and a calibration mark is scribed at a convenient place on wheel 110. Each division of the scale on wheel 113 can represent a suitable unit of lateral movement of wheel 113 on threaded neck 112, e.g., each unit can represent one-tenth of a millimeter of lateral movement. A bushing 114 can be used to space wheel 113 from ball 105 and thereby avoid interference during setting of the progressive side shift. After wheel 113- is threaded on neck 112, suitable means are preferably provided to limit the maximum lateral travel of wheel 113 on neck 112, e.g., a key can be inserted into bore 116 of neck 112. The key can then be used as a reference point for measuring the immediate lateral travel of the upper arm, e.g., the Bennet stop at its maximum expansion is placed with bushing 114 against ball 105. Screw 111 is then tightened to lock the stop on shaft 102 and wheel 113 is then backed off from contact with ball 105 by rotating it to advance it medially towards wheel 110 and provide a precise and measured side shift of member 100 between balls 105 and 106 that are mounted within condyle tracks 91 and 92. The degree of this lateral displacement can be read directly from the scale on wheel 113.

While my invention has been described by reference to an articulator having the condyle guides supported by arms attached to the mandibular case supporting frame, it is apparent that my means to permit a precise and measured immediate side shift can be utilized on all present articulators. The mounting axis of my invention in combination with a resilient face how such as described can also be employed to greatly simplify the setting of most dental articulators.

FIGURE 4 illustrates my invention applied to a conventional articulator that has the fossa or condyle tracks attached to the upper or maxillary frame support member. The articulator comprises an upper frame member 130 that supports a plate 131 and has a bore 132 and clamp 133 to support an incisal pin. Attached to each wing of member 130' are journal rings 134 and 135 in which are mounted condyle supports 136 and 137. The journal rings are slidably mounted on member 130 by

plates

140 and 141 thatare clamped by

screws

142 and 143. The condyle supports are rotatably mounted in the journal rings in the same manner as those described in FIGURE 2 and are similarly calibrated to indicate the horizontal inclination of the condyle tracks. The condyle supports rest on the condyle bearing balls such as 138 that are slidably mounted on support shafts such as 139. The support shafts are, in accordance with my invention, slidably mounted in sleeves such as 145 (shown at the right condyle support) which are rigidly attached to condyle

lateral support arms

146 and 147. The support shafts such as 139 extend through the lateralsupport arms and can be locked at any desired extention by lock screws such as 148. countersunk recesses such as 149 are provided at the outer ends of the support shafts to permit the face bow to be clamped to the articulator when mounting the case. The condyle

lateral support arms

146 and 147 are pivotably attached to

vertical support arms

150 and 151 and can be locked in any desired horizontal inclination by lock wheels 152 and 153. A scale, not shown is provided to indicate the angle of occlusion between the lateral and vertical support arms. The vertical support arms, in turn are rotata'bly mounted on

blocks

154 and 155 and locked thereto by

wheels

156 and 157.

Blocks

154 and 155 are, finally, mounted in tracks 64 and 65 of a lower frame member such as 50 illustrated in FIGURE 2, and clamped to the frame member by lock nuts (not shown) that engage threaded

shanks

158 and 159.

The Bennet stops of the conventional articulator comprises a pin that is supported by arm 160 between Bennet guides such as 161. Arm 160 is, of course, mounted in recess 59 of the lower frame member 50 shown in FIGURE 2. The timed Bennet shift upon lateral excursion is adjusted by rotating the Bennet guides with

wheels

162 and 163.

In accordance with my invention, however, the solid pin normally supported between the Bennet guides is replaced with sleeve 165 that is threaded on its interior surface. Hand wheels such as 164 are provided with threaded shanks that engage the threads on sleeve 165 so that rotation of the hand wheels will extend or retract the outer bearing points to or from the Bennet guides. Preferably, a scale is calibrated on the periphery of the wheels and a pointer (not shown) is mounted on arm 160 in front of the wheels as a reference point to indicate the degree of immediate side shift permitted in either direction.

Preferably, arm 160 is provided with a centric keying means such as arm 167 that is pivotably mounted in a slot at the base of the arm and a spring 168 is provided to bias the arm into a groove 1'69 centrically positioned in the upper frame member 130.

My invention can also be applied to provide an immediate side shift in articulators having Bennet guides that ride against stops which are separately mounted on the lower member of an articulator. Such a modification is illustrated in FIGURE 5 and reference is herein made to FIGURE 2 of US. Patent 2,816,360 and the number identification of elements in that figure will be used in FIGURE 5 but prefixed by 2. The Bennet guides comprise plastic blanks 286 supported by brackets 282 that are rotatably mounted to the upper frame 211 by studs 283 and locked thereto by nuts 285. In said conventional articulator, shift control balls 280 are rigidly supported on the crossbar of lower frame member 210.

In accordance with my invention, however, shift control balls 280 are eccentrically mounted to shafts 281 and said shafts are rotatably mounted in bores in said crossbar 210. A shoulder 201, washer 202 and lock nut 200 are provided to secure the shaft to the frame and, preferably, the upper surface of 201 is calibrated, as shown, to indicate the lateral retraction of balls 280 from guide plates 286.

The use of the invention in reconstructive dentistry is fairly apparent from the preceding description. The anterior tracing and check-bite system illustrated in FIG- URE 1 is used to obtain the anterior gothic arch tracings.

and to record the centric, protrusive and right and left lateral jaw positions in the wax coating on 15b and 18b. In use, the tracing pads 15a and 18a are coated with a suspension of talcum in a volatile solvent, e.g., alcohol, and the solvent permitted to evaporate and leave a talcum coating. The writing styli are inserted and the patient is instructed in jaw movements so as to register a Gothic arch on the tables. The styli are then removed and the registrations are covered with transparent tape. The writing styli are again inserted and the patient is instructed to hold steady in the various jaw positions necessary to record and the checkbite pin registrations are obtained by inserting the heated pins through the sleeve guides to melt the wax in the trays and record a recess in the wax. The clamp such as 49 is then moved down the pin until it rests on top of the sleeve and then the lock screw is tightened to preserve the proper vertical spacing of the tracing arm above the wax pad. This procedure is repeated for the centric, protrusive, and left and right lateral jaw positions.

As previously mentioned, various other pantographs can be used to obtain posterior and/or anterior tracings for setting the articulator. After the tracings are completed, the patient is returned to centric position and the vise grips are positioned and secured to crossbars 1 and 30 The telescoping mounting axis is then used to measure the distance between the hinge axis reference pins 12 and 13 on the face bow as it is removed from the patient. The upper frame member of the articulator is removed, the mounting axis inserted on the condyle tracks 91 and 92 and the support arms 66 and 67 are moved along tracks 64 and 65, respectively, to correspond with the predetermined reading on rod 80, obtained in the manner previously mentioned. The arms 66 and 67 are then locked in position and the face bow is engaged in the articulator by springing the free ends of side rods 2 and 3 apart to permit centering pins 12 and 13 to seat in the recesses of the mounting axis.

The axis-orbital plane support rod is used to support the face bow above the working surface. conventionally,

such rods are adjusted while the face bow is on the patient by resting an axis-orbital plane indicator on centering pins 12 and 13 and rod 90. The position of rod 90 is then adjusted so that the orbital pointer of the indicator is oriented to a reference point on the patient. Alternatively, rod 90 can be adjusted on the articulator to locate the clutches at a convenient level between the upper and lower members of the articulator. The mandibular clutch is then plastered to plate 60 in the conventional manner. When the checkbite system illustrated in FIGURE 1 is used, the centric checkbite pins such as 45 are clamped into

sleeves

43 and 48 by screws 46 and 47 with the clamps such as 49 of the pins resting on the sleeves. The maxillary clutch is positioned by resting it on the tripod formed by central bearing screw 57 of the mandibular clutch and the centric checkbite pins shown at 45 which are seated in their wax imprints on trays b and 1812. This correctly locates the maxillary clutch to the mandibular clutch in their centric position. Vise grips such as are then placed, two on crossbar and two on crossbar 1, so that the opposing vise grips are adjacent to each other and a quick setting cement is used to cement the adjacent grips together. Side rods 2 and 3, axis-orbital plane support rod 90 and the telescoping mounting axis 8081 can then be removed from the instrument and the upper frame member of the articulator, shown in FIGURE 3 is inserted in the instrument and centrically located with knife blade 94 of the centric keying means. The maxillary clutch is then plastered to plate 107 in the conventional manner and, after the plaster has hardened, the vise grips are removed to permit setting of the instrument. The horizontal inclination of condyle tracks 91 and 92 is then set on the instrument. To make this setting, the centric checkbite pins are replaced with the protrusive checkbite pins. The instrument is moved into protrusive position and the horizontal condyle guide set screws 77 and 78 are loosened and the condyle supports are rotated in their journal guides until the protrusive checkbite pins accurately seat in their impressions in the wax coating on trays 15b and 18b with the maxillary clutch resting on central bearing screw 57. Set screws 77 and 78 are then secured to lock condyle supports in their journal rings. It is apparent from the preceding description that the centric and the protrusive settings of the instrument with the checkbite pin registrations and the maxillary support on bearing screw 57 accurately establish the proper horizontal inclination of condyle tracks 73 and 74.

The vertical rotation centers are then set for proper lateral excursion of the instrument. To make this setting, the protrusive checkbite pins are removed and the writing styli are inserted into

sleeves

38 and 39. The side shift stops of my invention are set to Zero with wheel 113 extended against the key stop in 116 and the assembly is slid on shaft 102 until bushings 114 bear against condyle balls 105 and 106. Screws such as 111 are thereafter tightened to lock the stops on the shaft. The centric keying means is disengaged by tipping blade 94 away from groove 121. The instrument is moved in right and left lateral excursion to confirm the writing styli follow the median leg such as 99 of the Gothic arch tracings. If not, wheels 68 are loosened and the vertical rotation centers are repositioned until the median leg 99 of the Gothic arch tracings are followed by the writing styli.

Thereafter the immediate Bennet shift is set on the instrument so that the styli follow the immediate lateral tracing of the Gothic arch. This side shift can be seen in the lateral leg of the Gothic arch tracings, where at the beginning of the lateral movement there is a straight lateral tracing 21 of the styli before the lateral are 22 about the opposite rotational center occurs. The immediate side shift is adjusted on the instrument by rotating

wheels

113 and 119 of the Bennett shift stops of my invention to back bushings 114 and 122 away from contact with balls 105 and 106. This adjustment is made until the upper member of the articulator shifts laterally (immediate side shift) and the styli travel along line 21. The degree of this movement can be read from the scale on the Bennet shift stops and recorded with the other settings of the instrument for repeated settings of the instrument. The timed Bennet shift is then set on the instrument by loosening wheels 74 and 75 and moving the instrument into right and left lateral excursions while rotating members 69 and 70 until the writing styli follow the lateral leg or are 22 of the tracing. The writing styli are then removed and the lateral checkbite pins are inserted and the instrument is set for these positions in the conventional manner as previously described in setting the instrument for the protrusive position.

The writing device is then removed from the clutches and the articulator is keyed into the centric position with the centric keying means. The clutches are then cemented together with resin or similar material to form a bite fork that can be used for making subsequent transfers of the working casts to the instrument.

The mounting stone is then removed from the maxillary clutch, the upper member of the articulator is removed, and the telescoping mounting axis -81 is placed in the articulator. Clamp 16 is slid onto crossbar 30 and side rods 2 and 3 are also looked on the crossbar 30 by

clamps

4 and 5 and adjusted thereon so that centering pins 12 and 13 are engaged in recesses of the mounting axis 80-81. The axis orbital plane support rod is placed in clamp 16 and secured with the base of the rod resting on the working surface. The face bow assembly is then removed from the maxillary clutch for use in subsequent mounting of the bite fork in the articulator.

The teeth of the patient are then prepared, one quadrant of the upper arch at a time, and the area of the prepared teeth is perfected in the bite fork by painting in a minimal amount of softened low fusing compound, seating the bite fork on the lower teeth, and then instructing the patient to close in centric on the unaltered teeth. The perfected bite fork is locked into the aforementioned face bow assembly and the assembly is then used to accurately position the working model into the instrument. In this manner, repeated reference to tattoo marks on the patient is not necessary and this objectionable marking of permanent reference points on the patients face is obviated.

It will be obvious to those skilled in the art that various changes can be made without departing from the spirit of the invention and, therefore, the invention is not limited to what is shown in the drawings and described in the specification, but only as indicated by the steps and elements, and their obvious equivalents, set forth in the following claims.

I claim:

1. In a dental articulator useful for the reproduction of jaw movements and having upper and lower frame members adjustably hinged together along a hinge axis, the improvement comprising means permitting an immediate side shift of said members in a direction parallel to said hinge axis without protrusive movement and a stop to limit said immediate side shift, said means having adjustment means to set and precisely reset, in repeated remountings, the degree of said immediate side shift and means to register said degree of immediate side shift.

2,. The articulator of claim 1 wherein said adjustment means is controllable to i0.l millimeter.

3. The articulator of claim 1 also having a centric keying means on one of said frame members to hold the other of said frame members in a centric position.

4. The articulator of claim 1 wherein said stop means comprises a first stop means to generally limit said side shift, locking means to secure said first means in a predetermined position and adjustment means mounted on said first stop means to permit a precise adjustment of said immediate side shift.

5. The articulator of claim 1 wherein said upper frame member is mounted on a shaft passing through said hinge axis and wherein said stop means comprises a first stop member slidably mounted on said shaft, a sleeve threaded on its outer surface and attached to said first stop memher, a precise adjustment means engaged with the threaded surface of said sleeve, means to limit the maximum lateral extension of said precise adjustment means on said threaded sleeve and a scale on said stop means to indicate the expansion of said stop means.

6. In a dental articulator useful for the reproduction of jaw movements and having upper and lower frame members adjustably hinged together along a hinge axis, the improvement comprising means permitting an immediate side shift of said members in a direction parallel to said hinge axis, stop means adjustable to limit said side shift and a scale associated wtih said stop means to indicate the degree of said immediate side shift.

7. The combination of a face bow transfer means and one of the frame members of a dental articulator having first and second frame members hinged together along a hinge axis; said one of said frame members comprising a base with a cast mounting plate and support arms, mounting means supported on said hinge axis by said support arms at a fixed distance above a reference surface, said mounting means comprising a shaft removably mounted in said one of said frame members and having telescoping first and second sections, condyle bearing balls mounted on each of said first and second sections; countersunk recesses on the outboard ends of each of said sections; said face bow transfer means comprising a crossbar, cast support, and two sidearms attached thereto, each of said sidearm having one end clamped to opposite ends of said. crossbar, hinge axis centering pins clamped to said sidearms at the ends opposite said crossbar, said centering pins extending into said recesses to support said face bow on said frame member and a support rod clamped to said crossbar with its lower end resting on said reference surface and supporting said cast support at a predetermined height above said cast mounting plate.

8. The combination of claim 7 wherein said shaft has a scale calibrated to indicate the spacing between said condyle balls.

9. The combination of claim '7 wherein said support rod has a length equal to the fixed distance of said hinge axis above said reference surface.

10. The combination of claim 9 wherein said support rod is calibrated with degree of said predetermined height.

References Cited UNITED STATES PATENTS 1,666,022 4/1928 Phillips 32-32 1,703,105 2/1929 Hawksworth 32-20 1,733,507 10/1929 McCollum 3232 1,815,956 7/1931 Ralph 3232 2,235,524 3/1941 Lenty 32-32 2,262,574 11/1941 Chott 3232 2,334,643 11/1943 Moore 3232 2,814,876 12/1957 Stuart 32l9 2,816,360 12/1957 Stuart 32-32 3,052,030 9/1962 Spence 32-32 FOREIGN PATENTS 77,257 8/ 1948 Czechoslovakia.

RICHARD A. GAUDET, Primary Examiner.

J. W. HINEY, Assistant Examiner.