Jaw articulator and face bow with bite-fork column

Articulator for simulating jaw movements comprising an upper and a lower part for carrying an upper-jaw and/or lower-jaw model and connected by joints permitting one or more swivelling and linear motions, in which in the joint the lower part is guided relative to the upper part in one or more directions comprising components of motion in the cranial and/or dorsal direction and corresponding to surtrusion and/or retrusion.

FIELD OF THE INVENTION 
The invention relates to a articulator for simulating jaw movements, 
comprising an upper and a lower part for carrying an upper-jaw and/or a 
lower-jaw model and connected by joints permitting one or more swivelling 
and linear motions. The invention also relates to a face bow comprising a 
curved transfer member surrounding the face and for transferring and 
fitting a model jaw in the correct spatial orientation relative to the 
skull in an aforementioned jaw articulator; the end regions of the 
transfer member are equipped with scanners for locating the pivot axis of 
the hinge of the jaw, in order to attach it to the transfer member at the 
reference points of the hinge axis. 
BACKGROUND ART 
Devices of this kind are known in dental technology (compare W. 
Hoffmann-Axthelm "Lexikon der Zahnmedizin", Quintessens-Verlags GmbH 
Berlin, 1983; "Einfuhrung in die Zahnersatzkunde", Verlag Urban und 
Schwarzenberg, 1975). 
The jaw articulator is for simulating movements of the hinge of the jaw 
when dental and jaw models are inserted, and the articulator can 
practically completely simulate the motion of the jaws relative to one 
another outside the mouth. The main problem in jaw articulation is to 
provide an average simulation of substantially all movements of the human 
lower jaw relative to the upper jaw. Articulators known for this purpose 
have very many adjustment facilities. The adjustment is made in accordance 
with a pantographic (three-dimensional) recording of the individual 
movements of the patient's lower jaw made by the dentist. The recording is 
lengthy and expensive, taking about 2 to 3 hours for obtaining the 
information from the patient. The subsequent programming of the 
articulator in accordance with the pantograph takes about 3 to 5 hours. 
In other known articulators, the slope of the joint path is adjustable in 
the sagittal direction. The motion of the condyle can also be limited, 
i.e. adjusted, in the transverse direction (Bennett angle). The parts of 
the joints in these simulators, known as Arcom articulators, are designed 
in accordance with anatomical conditions, i.e. the condyles are disposed 
on the lower part of the articulator and the condyle casing or joint box 
with the device for adjusting the Bennett angle are disposed on the upper 
part of the articulator. However, these known articulators enable the 
respective ball or condyle to move laterally only; in which case the 
straight track of the second joint box or condyle moves in the median 
direction. Furthermore the balls are tightly encapsulated in their boxes, 
and consequently do not have degrees of freedom for components of motion 
in other directions. 
SUMMARY OF THE INVENTION 
Accordingly the invention is based on the problem of constructing an 
articulator having sufficient reserves for motion of the jaw, in order to 
model a dental prosthesis which is comfortable for the patient to wear and 
is physiologically compatible. To this end, as proposed according to the 
invention in the case of an articulator having the initially-dimensioned 
features, in the joint the lower part is guided relative to the upper part 
in one or more directions comprising components of motion in the cranial 
and/or dorsal direction and corresponding to surtrusion and/or retrusion. 
This guidance of the lower part of the articulator relative to the upper 
part in the joint permits average Bennett motions backwards or retrusively 
and/or upwards or surtrusively when modelling dental prostheses. This is a 
method of eliminating errors in simulating the occlusion of the upper or 
lower jaw; such errors would otherwise necessitate careful regrinding by 
the dentist and might possibly damage or destroy the entire masticatory 
system. 
DETAILED DESCRIPTION OF PRINCIPLES OF THE INVENTION 
In an embodiment of this inventive idea, the joint is formed with one or 
more linear guides which deviate surtrusively and/or retrusively from the 
direction of a common hinge-like axis connecting the joints. Angles of 
about 13.degree.-17.degree., more particularly 15.degree., have been found 
advantageous in practice, as regards the deviation of the surtrusion 
and/or retrusion components of motion relative to the hinge axis. 
Advantageously to this end, the angle between the hinge axis and the 
linear guide for obtaining the aforementioned retrusion and/or surtrusion 
is acute and preferably about 30.degree.. 
The advantage of guiding the Bennett motions (laterotrusion) in the cranial 
(surtrusion) direction also according to the invention, more particularly 
at an angle of 15.degree. to the hinge axis, is that the occlusion in the 
side-tooth region can be designed so that the freedom of motion of the 
lower jaw is additionally ensured in this direction. If the Bennett motion 
is guided not only laterally or cranially but also and particularly at 
15.degree. to the rear (retrusion) the advantage is that the motion of the 
lower jaw is lateral, cranial and retral instead of lateral and cranial 
only. This motion facility gives retral freedom in occlusion. 
In the case of articulators comprising joint parts constructed under 
anatomical conditions with a joint box for receiving a ball of a joint, 
the construction and manufacture are simplified or reduced in expense if, 
according to another feature of the invention, one or more sliding 
surfaces are formed in the joint box for components of motion of the ball 
in the cranial and/or dorsal direction or for surtrusion and/or retrusion. 
The sliding surfaces thus form the guides or tracks for the ball to give 
it the desired freedom of motion according to the invention. In principle 
these sliding surfaces or tracks can be curved or bent, but it is 
particularly advantageous for them to be linear or straight, at least in 
parts. 
According to another feature of the invention, account is taken of research 
results, according to which the joint box has internal or concave 
curvature, the average radius of the curvature being about three-quarters 
of an inch. The motion of the lower jaw thus differs from conventional 
average-value articulators in that the sagittal condyle track has a 
three-quarter inch radius. 
In order to adapt the jaw hinge articulation even better to individual 
peculiarities of the patient's teeth or dentures, according to another 
feature of the invention a guide duct is provided and extends through the 
joint box and opens into its interior and contains an adjusting means 
which is guided in reciprocation so that it can engage the ball or condyle 
and adjust it. In this manner, the balls or condyles can deliberately be 
brought into a latero-protrusive or protrusive position, so as selectively 
to balance an existing occlusion or to restore it. 
According to another feature of the invention, based on articulators with 
Bennett bevels on the joint for displacing the condyle, the Bennett bevel 
is disposed at a fixed angle of 10.degree. to the hinge axis of the joints 
or to the median plane. This results in adaptation to the per se known 
Bennett angle of 6.degree.-7.5.degree.. With regard to Bennett bevels, 
they are advantageously made adjustable between 0 and 3 millimeters to the 
median plane, in accordance with an existing scale with 0.5 millimeter 
divisions. This is a means of individually adjusting the direct median 
displacement (=immediate side-shift) of the condyle. 
In an alternative embodiment of an articulator having the 
initially-mentioned features, the upper and/or lower jaw each extend at an 
angle of 10.degree. to the horizontal plane. Advantageously the slope is 
upwards in the dorsal direction. In other words, the two parts of the 
articulator for the upper and lower jaw are not parallel to the horizontal 
plane but, measured relative to the occlusion plane, slope upwards by 
10.degree.. This has important advantages. Three-dimensional orientation 
of the upper jaw in the cranial direction is made easier by raising the 
frame in the posterior region. The articulator frame parts are thus 
brought near the occlusion plane. The expansion of the plaster of Paris 
used in fitting the dental prosthesis is compensated in more balanced 
manner. As a result of the aforementioned 10.degree. slope of the 
articulation frame, the assembly plate of the articulator is almost 
parallel to the base of the model, so as to counteract irregularities 
caused by the assembly material (expansion of the plaster). One advantage 
in manufacture, during lining, is that when the model is taken out, the 
occlusion planes lie parallel to the horizontal plane. A model taken out 
and standing horizontally on a table can be lined by using a metal into 
which the lining material is poured. Without the 10.degree. inclination 
according to the invention, the occlusion plane would be simulated at an 
angle. Finally, owing to the angular adjustment of the lower and upper 
articulation frame (the lower and upper part), the application of force 
can also be concentrated on the occlusion plane; as a result of the 
adjustment via the aforementioned 10.degree. inclination to the occlusion 
plane, the torque applied in closing the jaw is converted exclusively into 
a component of force directed at right angles to the occlusion plane. This 
avoids splitting into other, ineffective components of force parallel to 
the occlusion plane. This method of application of force ensures reliable 
and balanced occlusion. 
When handling articulators, it is desirable to be able to lock the upper 
part and lower part at the zero point of occlusion. To this end, in the 
case of an articulator having the initially-mentioned features, where the 
parts of the joint also permit transverse or lateral components of motion 
of the bottom part transversely to the median or sagittal plane and/or in 
the direction of the hinge axis of the joints, the invention proposes a 
first and a second locking element which are disposed on the upper and the 
lower part and can be releasably brought into engagement with one another 
so as to eliminate lateral components of motion of the upper and lower 
part relative to one another. The central static position of occlusion 
(zero point of occlusion) is locked in this manner. Of course, in order to 
simulate the Bennett motion in accordance with the first-mentioned 
alternative, the centric locking must be released, by disengaging the 
first locking element from the second locking element. 
In one construction corresponding to this inventive idea, one locking 
element is in the form of a notch or gap immovably attached to the upper 
and/or the lower part, whereas the other locking element is an insertion 
or engagement means pivotable in the first locking element and adapted to 
be secured and manipulated transversely or at an angle to the lateral 
direction; the last-mentioned means is hinged to the lower part or the 
upper part. According to another constructional feature, the gap is formed 
at the rear on the lower part by two hooks, which project side by side and 
are open at the top, and the engagement means is hinged to the upper part 
at the rear; on both sides it has lateral projections so that it can fall 
into the aforementioned open hooks. The advantage is that the articulator 
can be used either in one piece or divided, both in the open and in the 
closed, centrically locked state. 
In order to adjust the articulator to individual patients (e.g. the Bennett 
angle or the intercondylar distance), the measurements must be 
individually recorded on the patient. In the case of the sagittal condylar 
inclination and the Bennett angle for example, this can be done by means 
of face bows (extra-oral recording). For the purpose of intra-oral 
determination of the sagittal condylar path inclination, the patient in 
the protruded (forwardly moved) position is requested to bite on a bite 
fork in a wax recording device. In this case the condyles are in a 
position which is typical of the respective individual inclination of the 
joint track. If the wax recording device is inserted between the rows of 
teeth in dental jaw models secured in an articulator at an adjustable 
inclination of the condyle track, and if the model jaw is inserted exactly 
into the wax recording device, the movements of the articulator will 
substantially correspond to the individual movements of the patient's jaw 
hinge. The articulator joint can therefore be adjusted in this manner to 
the individual inclination of the patient's joint track. 
To simplify the manipulation of the hinge axis reference points for a 
patient and to locate them in accordance with his individual skull 
characteristics without inconveniencing the patient, in another 
alternative version of the invention, as proposed in the case of a face 
bow having the initially-mentioned features, the scanners are movable and 
lockable in the direction of the hinge axis. 
In order symmetrically to position the transfer member of the face bow 
relative to the median or sagittal plane of the human jaw, according to 
another feature of the last-mentioned alternative, the scanners carry code 
markings disposed symmetrically on the respective carrier relative to the 
jaw median plane or a central plane transversely to the hinge axis; the 
carriers can move in the direction of the hinge axis past reference marks 
disposed in a stationary position on the transfer member. In an embodiment 
of this idea, the scanners are bolts or pins which extend through the ends 
of the transfer member so as to be capable of reciprocation in the 
direction of the hinge axis, and comprise coloured recesses and/or raised 
portions in the form of rotating rings which constitute the symmetrical 
code marks. 
Optionally according to the invention the face bow having the 
initially-mentioned features is provided with a supporting projection 
which is positioned in a central portion of the transfer member and is 
adapted to abut the glabella (the hairless region between the eyebrows). 
Particularly advantageously the projection is movable, i.e. in the 
direction towards the glabella and/or at an angle or at right angles to 
the plane spanned by the transfer member, and is lockable in the position 
corresponding to the patient. The locking means can be one or more 
milled-head screws. This avoids the previously known adjustment of the 
transfer member to a non-exact average value relative to the glabella. 
If the glabella support and the previously-explained hinge axis scanners 
are secured in three dimensions, e.g. by milled-head screws, in accordance 
with the patient's individual characteristics, the problem of transport 
arises after the bite fork has been taken out. The bite fork and its 
guiding or supporting column must be delivered to the laboratory and 
mounted on the articulator with three-dimensional adjustment corresponding 
substantially to the geometrical characteristics of the individual 
patient's skull. To this end it is known to remove the supporting-pin 
plate from the lower-jaw part of the articulator and as a substitute to 
secure the guiding and supporting column with the bite fork. 
Faulty deviations of up to 8 millimeters can occur in the process. This is 
due mainly to alignment of the bite fork at an incorrect angle to the 
median plane of the jaw, e.g. if the guiding or supporting column and the 
bite fork secured thereto are not inserted and/or mounted in the 
articulator lower-jaw part in the correct rotary position relative to the 
skull. 
Accordingly the invention is based on the problem of providing a face bow 
which is easy to manipulate and can reliably transfer the angular position 
of the bite fork relative to the median plane to the articulator exactly 
in accordance with the characteristics of the individual skull. To this 
end according to the invention, in the case of a face bow comprising a 
guide column releasably secured to the transfer member in order to carry 
an adjustable bite fork, according to the invention, the transfer member 
has an elongate centring recess on its upper or lower side and the guide 
column has an adjusting projection for positive engagement in the centring 
recess. 
When the stationary centring recess on the transfer member engages the 
stationary adjusting projection on the guide column, the guide column is 
practically prevented from rotation, together with the bite fork secured 
thereon in the correct three-dimensional orientation relative to the 
skull. If the bite fork is not moved relative to the guide column, the 
guide column, via its adjusting projection, can be brought into a position 
in a suitable centring recess on the articulator, the position 
corresponding substantially to the three-dimensional conditions recorded 
on the individual patient's skull and fixed by means of the bite fork 
and/or the previously-explained hinge axis feelers. 
Advantageously the adjusting projection is in the form of a spike 
projecting vertically from the guide column and/or the centring recess is 
a V-section groove. As a result of this cross-sectional shape, the spike 
is guided in the central longitudinal plane of the groove up to its base 
or peak, where it is substantially non-rotatably secured. 
Exact adjustment relative to the patient's skull is facilitated if the 
centring recess extends approximately at right angles to the frontal plane 
of the jaw and/or the jaw hinge axis. The same applies if the centring 
recess extends approximately in the direction of the median plane of the 
jaw and/or lies in the central transverse plane of the transfer member. 
In order to mount the aforementioned guide column, comprising a bite fork 
bearing an individual wax record of the patient, in the articulator in a 
rotated position corresponding to the values measured by means of the face 
bow, according to the invention the articulator is provided with an 
adapter comprising a centring recess for positively receiving the 
aforementioned adjusting projection of the guide column. This appreciably 
increases the reliability and accuracy in manipulating the articulator. 
According to another feature, the articulator adapter according to the 
invention is formed with a bore for inserting and securing the guide 
column of the bite fork (e.g. by milled-head screws). The centring recess 
extends radially or at right angles to the bore. When therefore the guide 
column is inserted, its adjusting projection can serve as an abutment 
limiting the depth of insertion. 
In order to use the adapter according to the invention also in known 
commercially-obtainable articulators, according to another feature the 
adapter is in the form of a part which can be releasably secured to the 
upper or lower part of the articulator. The result, particularly when the 
adapter is fitted to the top part of the articulator, is a closed top unit 
corresponding to the model taken from the patient by means of the face bow 
and the bite fork. The aligned hinged-axis feelers or indicators on the 
face bow, which have located the actual hinge axis of the patient's jaw, 
reproduce the upper jaw and skull unit of the individual patient in 
identical manner in the top part of the articulator. By this means, the 
upper jaw on the articulator can be adjusted to fit the skull.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
As shown in FIGS. 1-3, the invention is embodied by an articulator 
comprising an upper part 1 pivoted to a lower part 2, adapted to bear an 
upper jaw and a lower jaw model respectively, on supporting plates 3 
disposed on the underside. The upper and lower parts 1, 2 are connected by 
joints 4 so as to be pivotable and movable in a straight line (compare 
FIG. 10). A supporting pin 5 mounted in the upper part 1 extends downwards 
to a guide plate 6 mounted on the lower part 2 and the supporting pin 5 
end rests on guide plate 6 in order to fix the bite height. A handhold 7 
and handle 8 projecting upwards from the upper part 1 are used to impart 
pivoting and linear motions 22, 45, 46, 47 to the upper part 1 relative to 
the lower part 2 to simulate the movements of the jaw hinge, the movements 
being transmitted by the joints 4. Articulators of this kind are known per 
se, and the technical literature should be consulted for further details. 
According to the invention, the upper and lower sides of the central 
portions 9, 10 of the upper part 1 and lower part 2 respectively, to which 
the supporting plates 3 are secured, are inclined at an angle 11 of 
10.degree.. As a result the central portions 9, 10 slope upwards, as seen 
in the dorsal direction 12 towards the joints 4. 
As shown more particularly in FIGS. 2 and 3, the articulator according to 
the invention is provided with a centric locking device 13 disposed on the 
back of the articulator between the joints 4 and comprising two locking 
elements 14, 15 disposed on the top and lower part 1, 2. The locking 
elements are disposed approximately in the middle of the rear crossbars 
16, 17 of the upper and lower part 1, 2. 
The construction and operation of the articulator joint part 4 will now be 
explained with reference to FIGS. 4-9. 
The joint part substantially comprises a joint box 18 which, on its 
underside visible in FIG. 4, is formed with a cavity 19 for receiving the 
ball 20 of a joint. The joint box 18 constitutes the respective end of the 
crossbar 16 of the upper part 1, and the ball 20 is disposed at the tip of 
a shank 21 secured to the lower part 2 in the top lateral end region of 
the crossbar 17. 
The ball 20 can roll on the wall bounding the cavity 19, which is concave 
and has a base radius of 3/4 inches. The upper part 1 can therefore be 
made to pivot 22 relative to the lower part 2, substantially around an 
(imaginary) hinge axis 23 through the respective centres of the balls 20 
of the two joints 4, so as to simulate movements of the lower jaw relative 
to the upper jaw. The hinge axis 23 extends perpendicular to FIG. 2 and in 
the plane of the drawing in FIGS. 3 and 4. 
In FIG. 4, the ball 20 in the dorsal direction abuts a guide surface 24 
forming a substantially straight track along which the ball 20 can slide. 
The guide surface or sliding track 24, as considered from medial to 
lateral, extends firstly in a portion parallel to the hinge axis 23 and 
then merges via a convex corner 25 into a sloping portion 26 which 
deviates from the direction of the hinge axis 23 by an angle 27 of about 
30.degree. in the retral/dorsal or retrusive direction. The sloping 
surface 26 consequently forms a guide surface or sliding track for 
simulating retrusion of the lower jaw relative to the upper jaw. The angle 
27 of 30.degree. results in a dynamic deviation of about 15.degree. of the 
ball 20 relative to the hinge axis 23. 
A through bore 28 opening into the cavity 19 of the joint box 18 has an 
inner thread in which a protrusion screw 29 can be rotated and thus moved 
in linear reciprocation. The bore 28 is aligned so that the protrusion 
screw 29 meshing therewith engages the ball 20 approximately in the region 
bounded by the sloping portion 26 and prevents it from retrusion or causes 
protrusion. 
In FIG. 5, a Bennett bevel 30 extends into the cavity 19 of the joint box 
18 and is mounted for reciprocation in the lateral/medial direction and 
can be locked in an internally threaded blind bore 33 by means of a 
milled-head screw 32. The part of the Bennett bevel which imparts a 
Bennett motion to the ball 20 is an arm 34 which projects into the cavity 
19 in the joint box 18. The part of the arm facing the ball 20 forms a 
sliding track for the ball and is at an angle of about 10.degree. to a 
line 35 extending parallel to the jaw median plane 44 or at right angles 
to the hinge axis 23. 
In FIG. 6, the ball 20 in the cranial direction also abuts the wall 
bounding the cavity 19 in the joint box 18. In the view in FIG. 6, the 
wall, as in FIG. 4, considered in the lateral direction 37, is divided 
into a first guide surface 38 parallel to the hinge axis 23 separated by a 
convex corner 39 from a following sloping portion 40 which diverges in the 
cranial or upward direction and is at an angle 40a of about 30.degree. to 
the hinge axis 23. The term "convex corner", designates an outerside 
corner as distinguished from an inside corner and means that the angle 
between the merging surfaces is greater than 180.degree. when measured 
through the air, and is less than 180.degree. when measured through the 
solid material. By this means, in addition to or alternatively to the 
15.degree. retrusion in FIG. 4, the ball 20 is given a motion reserve in 
the sense of a surtrusion of 15.degree. relative to the hinge axis. If the 
motion reserve needs to include both the 15.degree. retrusion (FIG. 4) 
and the 15.degree. surtrusion (FIG. 6), the convex corners 25 (FIG. 4) and 
39 (FIG. 6) can be regarded as points on a vertical line 41 which is drawn 
in FIGS. 8 and 9 and marks off the lateral guidance from the surtrusion 
and retrusion guidance of the ball 20. 
Furthermore, with regard to the aforementioned Bennett bevel 30, the 
outside of the joint box 18 in FIG. 1 is constructed as an information 
carrier, i.e. comprises a 3-mm adjustment scale 42. The scale co-operates 
with a reference mark 43 in the form of a straight line on the second arm 
of the Bennett bevel, through which the milled-head screw 32 extends. 
The horizontal plan in FIG. 10 additionally illustrates the operation of 
the retrusion and surtrusion guidance of the ball 20 on the lower jaw part 
2. The horizontal line corresponds to the hinge axis 23 whereas the 
vertical line 44 is a plan view of the jaw median plane. In conventional 
articulators, the balls 20 can in any case move laterally, i.e. in the 
laterotrusion direction 45. For additional clarity, the "immediate side 
shift" 46a is also shown by a shaded triangle extending in the region 
bounded by the hinge axis 23 and the median plane 44. The protrusion 
parallel to the medial plane 44 is marked 46. The sloping portion 26 in 
FIG. 4 is for retrusion 47 of the ball 20, as illustrated by the shaded 
triangle marked 47, which extends outside the region bounded by the hinge 
axis line 23 and the median line 44. The diagram in FIG. 10 can also be 
interpreted as a frontal plane, in which case the last-mentioned shaded 
triangle 47 will represent the surtrusion, brought about by the sloping 
portion 40 in FIG. 6, which serves as a sliding and guiding track for the 
ball 20. 
The centric locking means 13 will be explained in detail with reference to 
FIGS. 3, 11 and 12. The first locking element 14 is connected via a pivot 
48 to the upper part 1 of the articulator. It is in the form of a narrow 
insertion means which, owing to its flat shape, can easily be pivoted 49 
either to the second locking element 15 or into an abutment gap 50, 
disposed at the rear and centrally in the crossbar of the upper part 1. In 
FIG. 11, the lug 51 of the first locking element or insertion means 14 has 
struck the end 52 of the gap 50. In the position in FIG. 11, the ball 20 
can move laterally relatively to the joint box 18. To prevent such 
movements, i.e. for centric locking of the upper and lower parts 1, 2 
relative to one another, the insertion means is pivoted 49 downwards into 
the position in FIG. 3. In this position, the handling attachment 52 of 
the insertion means 44 is pushed into a locking gap 53 bounded by two 
upwardly open catch hooks 54. The hooks together form the second locking 
element 15 or its locking gap 53 and secure the attachment 52 or upper 
locking element 14 to the upper part 1. On each side, the upper part has a 
laterally extending suspension projection 55 which, in the centrically 
locked position in FIG. 3, abuts the crossbar 17 of the lower part 2 but 
has not yet been fully pushed or received in the catch fork formed by the 
two spaced-apart hooks 54. This is possible only when the ball 20 has been 
disengaged from the joint box 18 and is free as per FIG. 12. In that case 
the top part 1 and joint 48 is moved relative to the crossbar 17 backwards 
(dorsally) and downwards (caudally) so that the projections 55 rest in the 
two hooks 54 forming the fork. The upper part can then be pivoted through 
about 180.degree. around the joint 48, so that the e.g. rubber-like handle 
part 8 of the handhold 7 rests on a table surface or the like. This 
position (not shown) is suitable for attaching upper or lower jaw models 
100 to the plates 3 (see FIG. 2) or removing them therefrom. 
In FIG. 13, a face bow comprises a curved transfer member 60 for receiving 
and transferring a model jaw in the correct three-dimensional orientation 
relative to the skull in the previously-explained articulator. Measuring 
pins 62a, 62b extend through the end regions 61a, 6lb respectively and are 
guided for movement in bores 63a, 63b. The guide bores 63a, 63b are 
symmetrically aligned with one another so that the two pins 62a, 62b or 
their respective sliding movements 64a, 64b are in a common alignment 65. 
In order to locate the reference points for the jaw hinge axis on the 
human skull, the padded heads 66a, 66b (e.g. of plastics) of the pins 62a, 
62b are inserted part of the way into the patient's auditory canals and 
secured in position by milled-head screws 67. Care is taken to keep the 
end regions 61a, 6lb of the transfer member 60 at the same distance from 
the sides of the patient's face or his auditory canals. To this end the 
pins 62a, 62b each carry coloured coding rings 68a, 68b. In order to set 
equal distances to the patient's auditory canals, the code rings 68a, 68b 
are moved past the associated reference marks 69a, 69b or fixed relative 
to them. By means of the colour coding, the adjustment can be made so that 
the padded heads 66a, 66b project from the ends 61a, 6lb of the transfer 
member for the same distance towards the auditory canals, so as to obtain 
symmetry relative to the jaw median plane. 
The face bow in FIG. 13 is also attached by using the patient's glabella, 
by means of a supporting projection 70. The projection 70 is guided in a 
straight line on the top surface of the transfer member 60, in its central 
portion 71 and at right angles to the plane of the transfer member. The 
guide system comprises two parallel rods 72 which can be inserted into a 
central raised portion 73 and locked by a milled-head screw 74. Another 
guide for the glabella supporting projection 70 is provided parallel to 
and at a distance from the plane spanned by the transfer member 60. The 
second guide is in the form of a shank 76 bearing a glabella pad 75 and 
movable in reciprocation in a bore 77 and adapted to be locked therein by 
a milled head screw 78. The distance from the guide bore 77 to the 
transfer member 60 can be adjusted by moving the two rods 72 and securing 
them by the screw 74. The two rods 72 are for stabilising the alignment of 
the guide bores 77 relative to the glabella. They therefore bear an 
attachment 79 through which the guide bore 77 extends. 
Below the central raised portion 73 of the transfer member 60, a guide 
column 80 is movable and can be received and locked by a milled head screw 
81. As shown by the plan view of the underside of the transfer member 60 
in FIG. 14, a guide bore 83 extends transversely through a centring groove 
82 having an approximately V-shaped cross-section. 
The guide bore 83 is aligned so that the guide column can move at right 
angles to the plane spanned by the transfer member 60. The abutment 
element is an adjusting spike 85 which is attached to the guide column 80 
and projects vertically therefrom and, if necessary, rests in the centring 
groove 82 when the guide column 80 is inserted into the guide bore 83. The 
spike 85 is also used for securing the guide column 80 in a rotary 
position in the transfer member 60. Next, a bite fork 86 (compare FIG. 13) 
in the patient's mouth (not shown) and bearing a wax recording means 87 
with impressions of the patient, is secured to the guide column 80 by 
clamping elements 88. During the securing process, the measuring pins 62a, 
62b of the transfer member 60 are positioned in accordance with the jaw 
hinge axis of the patient. 
Next, as in FIG. 15, the guide column 80 is released from the transfer 
member 60 and partly inserted into an additional guide bore 89 (compare 
FIG. 16) through an adapter part 90 secured to the upper part 1 by a 
milled-head screw 91. When the guide column 80 is inserted 84 further into 
the adapter guide bore 89, the spike 85 comes against the top of the 
V-section centring groove 92 on the underside of the adapter part 90, as 
shown in FIG. 16. 
This position can be fixed by a milled-head screw 93 operating in the guide 
bore 89. The guide column 80 is thereby rotated into the same position as 
its previous position in the transfer member 60 of the face bow in FIG. 
14. 
The bite fork 86 has been fixed in the correct three-dimensional position 
relative to the skull by means of the clamping elements 88. If no change 
has been made in this position, the bite fork 86 in the articulator has a 
three-dimensional orientation to the hinge axis 23 of the two balls 20 
(compare FIGS. 1 and 10) which corresponds very closely to the 
characteristics of the patient, as measured by the pins 62a, 62b, the 
glabella supporting projection 70 and the bite fork 86 and wax recording 
means 87. 
The adapter 90 is a part compatible with the conventional articulator upper 
part 1, and can be replaced by the holding part 94 for adjusting the 
height of the supporting pin 5 (compare FIG. 1). To this end the adapter 
part 90 has a raised elongate rear web 95 which can be inserted into the 
front slot 96 in the upper part 1 of the articulator (compare FIG. 15 and 
FIG. 1).