Note: Descriptions are shown in the official language in which they were submitted.
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TI~L~: D~'~TTAL ARTIC[JL~TOR AND METHOD
~ACI~r,ROIJ~lD o~ T~IE I~ .N~
, This invention relates ~enerally to a dental articulator, and
~ more rarticularly to im~rovements in the counling portions of the
articulator and to a metho~ for ac'nie~tin~ said i~prover.ents.
Attempts to develo~ useful instrumentation to follow man~i-
¦ bular move~ents througl~ 211 its nositions and excursions aremanifold. ~he ~ovements of the mandihle are three dimensional
with riglt and left articular elements ~erformin~ similar or
dissimilar movements depenclin~ on anatomical for~. and tile
functions ~erformed. ~ince the t~o joints are intercon~ected,
j movement in one ~oint will have an effect on its counter~art.
The chief determinants for rebuilding the patient's occlusion
; 15 with fidelity are the recordin~ and transferring of the motions
of the mandible from t:~e patient to the ~ental articulator used
in such re~uildin~.
Dental articulators fall into ~ive ~eneral cateqories
according to function:
a. ~~in~1e hine which opens and closes.
D. ~e~i-adjustable which hin~e.s and also ~erforms ~rotrusiv~
and lateral movements which are quided hy avera~e
setting.s.
c. Ad~ustable articulators which utili2e intra-oral ~osi-
__ _ _ _ _ _, __
tional jaw records from the patient in centric and
eccentric positions to set straiqht line ~uiding
i surfaces or cams in the articulator.
d. Adiusta~le articulator~ w h extra-o al ?anto~ anhic
tracings in which the entire tracin~.s are used to set
-30 ' the a~?pro~riate articulator.
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1 2~340Al
! e. Adjustable articulator utilizin~ intra-oral ~olded
pathway~ which are then transferred to an articula~or b~
molding condylar pathways in the articulator.
The a~orementioned earlier methods are faultv either in their
i inabilit~ to capture the three dimensional as~ects in recordin~
the data or in the ~ani~ulative difficulties with the articu-
lator s acceptance of ~he records or in the transfer of the
patient s dental ~0~21s to the articulator in pro~er three
l dimensional orientation to the records. The customized analogs
however aive a closer ap~roxiration to the action of the
natient s own mandihular joints than do the mechanicall-~ adjust-
ahle joints or those with av~ra~e settinqs.
It is accordin~ly an object of the present invention to
I ~rovide an im~roved customized analo~ for reproducin~ the action
of a dental ratient s tem~oroman~ibular joints.
It is another object of this invention to ~rovide an analo~
customized for an individual dental ~atient which may be readil~
and simnly a~se~led as a dental articulator to reproduce the
motion of the ~atient s temporomandihular ~oints.
Another ob~ect of this invention is to ~rovide an i~roved
me~hocl of for~in~ an accurate analo~ of a dental ~atient s
temnoromandibular joint.
A further object of the ~resent invention is to provide a
method and a~aratus ~or formin~ an analoq of a tem~oromandi~ular
2~ joint and accuratelv relating the ~atient s dental wor~in~ model
in the assembly of the dental articulator.
These objects and other objects and advantaqes of the
invention will he a~arent from the followin~ descri~tion.
SUMMARY OF T~iE INVENTION
The above and other beneficial ob~ects and advantages are
accomplishe~ in accordance with the present invention by a
metllod and associated apparatus which construct monolithic
three-dimensional bearing surfaces representing condylar path-
ways, and pivotably mount said surfaces upon stationary upri~ht
condyle bslls in a dental articulator.
The apparatus is comprised of: 1) a maxillary recording
assembly adapted to attach to the upper jaw, 2) a mandibular
recording as~embly adapted to attach to the lower jaw, 3) an
upper articulator member, and 4) a lower articulator member
adapte~ to pivotably engage said upper articulator member.
The maxillary recording assembly is comprised of a first
rigid U-shaped bow having a straight forward bar and two
extremities positioned at eqllal distances rearwardly of said
forward bar, box-like receptacles remova~ly attached to said
rearward extremities, and an upper bite plate (also known as a
clutch) pendantly attaclled to sai(l ~orward bar and displaced
rearwardly therefroln.
The mandibular recordlng assembly, adapted to be positioned
beneath said maxillary assembly, is comprised of a second rigi~
U-shaped bow haYing a straight forwar~ bar and extreDIities
provi~ed with po.sts perpendicularly adjustable with respect to
said bow, said posts having affixed to thelr upper extremities a
ball made of a polytetrafluoroethylene such as that sold under
the trademark "TRFLON", which ball is adapted to enter the recep-
tacles of said maxillary assembly. A lower bite plate or clutch
is attached to said forward bar in substantially coplanar relation-
ship therewith and extending rearwardly therefrom to a position of
3~ vertical alignment with said upper bite plate.
The upper articulator member is comprised of a rigid plate
having a centered aperture, equal left and right side arms
radiating away from said aperture in a straight line path, and an
arm extending forwardly of said aperture in perpendicular dis-
position to said side arms. A mounting ring is held to the
underside of the plate by a threaded bolt that penetrates said
aperture. The distal extremity of said forwardly directed arm
holds a vertically adjustable post. The distal extremities of
said side arms are provided with means which permit accurate
attachment of the aforesaid receptacles.
The lower articulator member is comprised of a horizontally
disposed floor plate, a main cross bar supported above the rear
extremity of the plate which accommodates vertically positionable
left and right Teflon balls adapted to enter the receptacles
attached to the upper articulator member, a centrally located
threadably attached mounting ring, and an incisal guide table
positioned atop the plate adjacent its forward extremity.
BRIEF DESCRIPTION OF T~IE DRAWING
For a fuller understanding of the nature and objects of the
invention, reference should be had to the Eollowing detailed
description taken in connection with the accompanying drawing
forming a part of this specification and in which similar
numerals of reference indicate corresponding parts in all the
figures of the drawing:
Figure lA is a top plan view of an embodiment of the
maxillary recording assembly of this invention.
Figure lB is a bottom view of the maxillary recording
assembly of Figure lA.
Figure lC is a front perspective view of the maxillary
recording assembly of Figure lA.
Figure 2A is a front perspective view of an embodiment of the
mandibular recording assembly of thls invention.
Figure 2B is a bottom view of the mandibular recording
assembly of Figure 2A.
Figure 2C is an enlarged top view of the lower bite plate
o~ ~
snown in Figure 2A.
Figure 2D is an enlarged fragmentary perspective view of an
¦ ex~remity of the mandibular recording assembly shown in Figure
¦ 2A.
, F~gure 3A is a side view of the interengaged maxillary
¦~ and mandibular recording assemblies illustrating the method of
their use.
Figure 3B is a front view of the interengaged recording
assemblies of Figure 3A.
ln i Figure 3C is an enlarged fragmentary bottom view of the
receptacle components of said maxillary recording assembly as
shown in Figure lB, one of said receptacles being shown con-
taining a condylar pathway, the other receptacle being shown
' containing an axis orientation pointer.
1 Figure 4A is a top perspective view of an embodiment of an
upper articulstor member of the present invention.
Figure 4B is a bottom perspective view of the articulator
member of Figure 4A.
Figure 5A is a front perspective view of an embodiment of the
I lower articulator member of this invention.
Figure 5B is a rear perspective view of the articulator
i member of Figure 5A.
¦~ Figure 5C is a fragmentary rear view of the assembled upper
and Iower articulator members showing an optional centric lock
I mechanism.
I Figure 6 is a side view showing the manner of transitory
¦ interengagement of the maxillary recording assembly with the
upper articulator member.
~ Figure 7 is a side perspective view of the assembled upper
~ and lower articulator members in association with models of the
¦ patient's teeth.
1 For convenience in description, the terms "front" and "rear",
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and words of similar import, will have reference to the right and
¦~ left extremities, respectively, of the apparatus as shown in
Figure 7. Similarly, the terms "left" and "right" will have
reference to the left and right portions, respectively, of the
component of the apparatus illustrated in Figure 4A ar.d com-
ponents suitably oriented thereto. The expression "interior" or
equivalents thereof will in general have reference to the
geometric center of the apparatus shown in Figure 7
D~SCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figures lA, lB, lC and 3A, 3B, 3C of the
¦' drawing, the maxillary recording assembly 64 is shown comprised
of a substantially U-shaped first rigid bow 5 having a straight
¦ forward bar 65, and two extremities 66 positioned equidistantly
I rearwardly of said forward bar. The bow is bounded at its top,
bottom, exterior edge and interior edge by substantially flat
surfaces 67, 68, 69 and 70, respectively. Shoulders 76 protrude
jl inwardly from interior edge 70 adjacent extremities 66.
¦l Left and right box-like receptacles 4L and 4R, respectively,
I are securely but removably fastened to the extremities of bow 5.
I Each receptacle is comprised of a flat upper surface 71, a flat
lower surface 72 surrounding a recessed molding cavity 59, flat
sidewall edges 73, and an attachment arm 74. The receptacles are
attached to bow 5 by means of cap screws 7 which penetrate holes
¦ provided in the bow and engage threaded holes 6 in attachment arm
j 74. In such position of attachment, it is to be noted that the
~, attachment arm 74 is in abutment with the interior edge 70 and
shoulder 76 of the bow. When ready for use in recording a
patient's condylar pathways, the cavity 59 of each receptacle is
' filled with a plastic non-elastic recording clay composition
i 30 capable of being hardened with minimal dimensional change.
Suitable compositions include monomers and prepolymers capable of
undergoing addi~ional-type polymerization in the presence o~
catalytic species to form solid products. Such compositions,
generally referred to as auto-polymerizing materials, may for
example contain cyanoacrylate substances polymerizable by
peroxide-type free radical catalysts. Such compositions may also
3 incorporate solid powder lubricants such as Teflon, graphite,
talc and molybdenum disulfide. In some embodiments, thin plates
23 as shown in Figure 3C, containing a circular indentation 77,
may be placed within the molding cavity, their presence being
useful as positioning guides for the subsequent recording step.
An orientation pointer 8 of threadably adjustable length may be
removably associated with the interiorly directed portion of the
sidewall edge 73 of each receptacle, said pointers being directed
toward the interior of the bow, and used to position the
¦appnratus upon the patient relative to the patients mandibular
condyles. A hardened composition having a condylar tracing or
pathway 60 is shown filling one cavity 59 in Figure 3C.
An upper bite plate 9, also known as a maxillary clutch, is
¦¦pendantly attached to forward bar 65 by a slidable fastener 11
and post lO depending therefrom. Movement of fastener ll upon
¦¦bar 65 is controlled by set screw 78.- A support bar 79 extends
connectively between the lowermost extremity of post lO and
maxillary clutch 9. Such arrangement of components allows for
positioning of the maxillary recording bow in horizontal align-
ment with the midline of the face and vertically aligned with the
Frankfort Plane (axis orbital plane). Said maxillary clutch is
upwardly and rearwardly domed. A trough 80 extends about the
front and sides of the upper surface of the clutch, said trough
being adapted to receive a material such as a paste of zinc oxide
and eugenol which forms maxillary tooth imprint 6?. The under-
side of the maxillary clutch is comprised of a forwardly disposed
upwardly curved bearing surface 57 and opposed substantially flat
side portion 58.
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¦ The mandibular recording assembly 81, as shown in Figures 2A,
¦1 2B, 2C and 2D, is comprised of second rigid U-shaped bow 12
~¦ having s~raight forward bar 82, and rearwardly disposed
¦1 extr mities 83. The bow is bounded at its top, bottom, exterior
~l edge and interior edge by substantially flat surfaces 84, 85, 85
ij and 87, respec~ively. A smooth bore circular cylindrical channel
Il 88 is perpendicularly disposed to said top and bottom surfaces
¦¦ a~jacent extremities 83. A cylindrical post 13 is adapted to
l slidably engage channel 88. The uppermost extremity of said
¦ post, located above top surface~84, i8 provided with an attached
Il ball 149 preferably fabricated of Teflon material. The posi~ion
!1 of the ball above said top surface is fixed by cap screw 16 which
penetratively engages a threaded channel communicating
I horizontally between outside surface 86 and channel 88. The
balls are spaced in a manner to enter the respective receptacles
of the overlying maxillary recording assembly.
A lower bite plate or clutch 19 is attached by extension bar
21 and slidable fastener 22 to forward bar 82 in substantially
I coplanar relationship therewith and extending rearwardly ~here-
¦¦ from to a position of vertical alignment with said upper bite
¦I plate. The underside of bite plate i9 is provided with a
U-shaped trough 100 adapted to receive an imprint paste such as
that used in upper bite plate 9. A vertically adjustable bearing
I stud 20, extending upwardly from the substantially flat upper
Ij surface 89 of said bite plate, is centered within the ~agittal
1 plane represented by dashed line 90, and is adapted to engage thè
¦I curved forward bearing surface 57 of said upper bite plate. An
¦I L-shaped guide pin 17 i9 slidably engaged by channel 91 in close
¦I parallel juxtaposition to channel 88. A threaded lock bolt 18
¦I penetrates an edge of the bow to fix the position of pin 17
¦ within its channel. The function of guide pins 17 is to aid in
¦ the proper positioning of balls 14 when the receptacles are
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filled with the recording material.
Upper articulator member 92, as shown in Figures 4A, 4B and
7, is comprised of rigid base plate 24 having flat upper and
lower surfaces 93 and 94, respectively, a boundary sidewall 95,
and a penetrating bolt 25 centered in said sagittal plane and
extending beneath lower surface 94 and perpendicular thereto.
Opposed equal right and left side arm portions 2~ and 29,
respectively, extend away from the sagittal plane in a straight
;~ line path. A forward arm portion 34 extends from said bolt in
~ centered relationship to the sagittal plane and in perpendicular
disposition to said side arm portions. A mounting ring 27 is
held tightly to lower surface 94 by bolt 25. The forwardmost or
distal extremity of arm 34 holds vertically adjustable post 2
whose position is locked by constricting collars 35 or equivalent
means.
The distal extremities of side arms 28 and 29 are provided
with penetrative threaded bolts 31 adapted to extend below lower
surface 94 and into engagement with holes 22 in upper surface 71
of attachment arm 74 of the corresponding receptacles 4L and 4R.
In some instances, a spacer block 32 may be inserted between the
lower surface of the side arm portions and the underlying
receptacle to provide adequate space for mounting the patient's
maxillary model. By virtue of the aforesaid arrangement of com-
~ ponents, the receptacles are adapted to be transposed from the
2~ maxillary recording assembly into the upper articulator member;
and during said transposition the receptacles are secured to both
the maxillary recording assembly and upper articulator
member. Base plate 24 of said upper articulator member may be
further provided with a rear extension 36, the underside of which
~ supports paired pivot pla~es 37 held by bolts 40 which extend
through channels 38 and into threaded recesses 39.
Lower articulator member 96, as shown in Figures 5~, 5B, 5C,
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and 7, is comprised of horizontally disposed floor plate 43, the
underside of which is provided with one forward and two rearward
adjustable bolt footings 55 and 56, respectively. Posts 44
support main cross bar 45 above the rear of said floor plate in
parallel relationship therewith and perpendicularly disposed to
the sagittal plane. Left and right balls 14 atop posts 13 are
vertically positionable above cross bar 45 by virtue of sliding
engagement of posts 13 within close-fitting channels 46. Set
screws 50 lock posts 13 within channels 46. Said post and ball
combinations are preferably identical to those earlier described
with respect to mandibular recording assembly 81. The lateral
and vertical positioning of the balls is such as to facilitate
engagement with condylar moulded pathways 60 within overlying
cavities 59.
A lower mounting ring 48 is held fast upon the upper surface
of floor plate 43 by centered mounting bolt 52 acting from the
underside of said floor plate, Said mounting ring facilitates
attachment of the patient's mandibular model 54 as shown in
Figure 7. A positioning stud 53, rising upwardly from said floor
plate, engages mounting ring 48 to ensure precise positioning of
the ring and model 54 mounted thereupon. An upraised platform 3
having a flat upper surface is positioned upon floor plate 43
adjacent its forward extremity. The upper surface of said
platform serves as abutment means for the lowermost extremity of
adjustable post 2 of said upper articulator, as shown in Figure
7. The upper surface of the platform may alternatively be
contoured to have angular indentations or a custom molded
configuration produced from a clay-like composition comprised of
~ autopolymerizing resin. It is to be noted that the upper
extremity of post 2 is shown to have a curvsture representing an
arc of a circle centered upon a line drawn between the centers of
balls 14. Such configuration ensures that, despite vertical
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adjustments of the post, its lowermost extremity will remain in
the same position upon said platform.
A pivot post 1 is rotatably held by bearing block 97 slide-
! ably positioned upon cross bar ~5. The rotative position of the
post is ixed by set screw 98. Movement of the bearing block
along cross bar 45 is fixed by set screws 51. The pivot post is
adapted to be embraced by pivot plates 37 pendant from the upper
articulator member.
A channel 99 penetrates said pivot post in a horizontal
direction at a height above said cross bar defined by a line
drawn between the centers of the balls. A pivot pin 42 remov-
ably extends through said pivot plates and the channel in said
pivot post. Such assembly constitutes optional means for
pivotably interengaging the upper and lower articulator members
lS so that movement of the upper member toward or away from the
lower member is restricted to motion in a vertical path. The
pivotal plates 37 are secured to plate 36 in their rearmost part
so that they may be loosened and turned out of functional use
subsequent to removal of axis pin 42.
In the method of this invention, the maxillary and mandibular
clutches 9 and 19, respectively, are fabricated either intra-
orally or on a conventional hinge type articulator. The facing
surfaces of the clutches are adjusted and polished so that
; b~aring post 20 contacts the curved forward portion of the
underside of the maxillary clutch, and the peripheral areas of
the facing surfaces have smooth simultaneous contact, thereby
preventing rocking of the clutches about the bearing post.
The bows are positioned so that balls 14 are seated within
~ the depressions 77 of plates 23 located within cavities 59. The
positions of the balls are then adjusted such that there will be
no contact with the cavity walls in all possible movements. In
such positioning adjustments pointers 8 may be used to secure
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precise orientation with the condyle axes, thereby providing
greater fidelity of the molded pathways to the actual movements
i of the patient's condyles. Plates 23 and said pointers are then
ll removed, and the cavities are filled with recording clay. The
clutches are then cem~nted to the maxillary and mandibular teeth
of the patient using a paste of zinc oxide and eugenol.
The balls are manually seated into the cavities 59 filled
with the aforesaid hardenable clay-like plastic composition until
1 the original preclay position of the Teflon balls is achieved.
Said preclay position is located using the L-shaped pins 17
located on the mandibular bow, said pins functioning as depth
gauges. The balls, now in contact with the plastic composition,
function as forming balls.
' As shown in Figures 3A and 3B, the patient begins molding the
15 I condylar pathway, starting from the most retruded mandibular
position. The patient is asked to protrude and retrude his lower
jaw and subsequently to perform right and left lateral mandibular
movements. Such action produces three-dimensional impressions of
ll' said motion. The impressions mag be added to and lubricated and
20 ¦I re-inserted for achieving the most accurate result. After finely
detailed, accurate condylar pathways 60, as shown in Figure 3C,
have been established and hardened to constitute stable solid
recordings, the maxillary and mandibular recording assemblies are
~I removed from the patient. The aforementioned procedure allows
~ for diagnostic visual observation of the reproduced condylar
1~ pathways which yields additional information about the synchrony
il or asynchrony of the condylar movements as well as the timing of
the movement in each condyle for each basic movement. These
I¦ observations allow the operator to simulate these movements
30 1l during dental fabrication procedures. This arrangement also
allows ~or three dimensional analysis of condylar pathways.
In the mounting procedure, the patient's maxillary model 61
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is qeated in the zinc oxide and eugenol paste imprints 62 in
maxillary bite plate 9. The base plate 24 of the upper
articulator member with attached mounting ring 27 is next secured
-- to the box like recepticles 4R and 4L of the maxillary recording
, apparatus. This is accomplished utilizing cap screws 31 which
penetrate spacers 32 and engage holes 22 in the upper surface 71
of the receptacles. By virtue of such procedure, the maxillary
bow is directly transformed in~o an upper articulator member.
~ The patient's maxillary model is next affixed to the mounting
ring 27 of the upper base plate 24 utilizing dental mounting
plaster. In such manner of association the teeth of the
patient's model 61 seat within the imprint 62 of the upper bite
plate 9 and is secured to upper mounting ring 27.
Cap screws 7 are then removed, a procedure which permits
~ removal of first bow 5, with attached upper bite plate which is
then set aside. This procedure ensures complete fidelity in the
orientation of the patient's maxillary model 61 to the molded
condylar pathways 60 and further ensures that the mounted models
in the articulator have the same occlusal plane inclination
relative to the Frankfort Plane as the patient's jaws have in the
head. If methods other than this direct one are used, serious
orientation errors could result. The aforesaid procedure
essentially converts the maxillary recording assembly into an
upper articulator member~ with the patient's maxillary model 61
mounted and accurately oriented to the molded condylar pathways
60. It is to be noted that the apparatus component heretofore
referred to as the upper articulator member is in actuality
merely a precursor of the completed member.
Subsequently, the upper articul`ator member with the mounted
maxillary model and condylar pathways is placed on the Teflon
balls 14 of the lower articulator member as shown in Figure 7.
Since the medio-lateral distances of the Teflon balls 14 in the
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mandibular recording apparatus and the Teflon balls in the lower
articulator member are identical, the upper condylar pathways fit
accurately to the lower Teflon articulator balls which now
function as tracing balls. Since the balls are in the most
superior position in the clay paths in the centric relation jaw
" position, the orientation of the balls to this position is very
easy and very stable. With upper and lower articulator members
in proper interengagement and held in place with elastics over
the receptacles containing the condylar pathways, the patient's
i mandibular model 54 is mounted to the lower articulator member
utilizing an interocclusal record 63, as shown in Figure 7. The
assembled articulator by virtue of its specialiæed features,
¦l requires no centric lock for patients with normal condyles. Said
Il interocculusal record is composed of a stiff wax and zinc oxide
~1 and eugenol paste and taken in centric relation position. This
1l completes the mounting of the patient's models in proper
¦ relationship to the condylar pathways. The assembled articulator
is capable of accurately reproducing condylar and mandibular
__~ ¦ motion in its entire merge as well as opening and closing,
¦I without deviation, on the same radius of the arc of closure as
the patient in the retruded condylar position.
While particular examples of the present invention have been
' shown and described, it is apparent that changes and
modifications may be made therein without departing from the
~j 25 ¦il invention in its broadest aspects. The aim of the appended
;I claims, therefore, is to cover all such changes and modifications
¦ as fall within the true spirit and scope of the invention.
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