Maxillomandibular jaw
relations
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Definition :
A record base or base plate is a temporary form
representing the base of a denture. It is used in
recording maxillomandibular relations and in the
arrangement of the teeth.
Requirements :
should be rigid.
should be accurate.
should be stable.
the borders should be round & smooth as the borders of
finished dentures.
should be thin at the crest ,labial & buccal slopes to
provide space for tooth arrangement.
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Definition : occlusion rims are occluding surfaces
constructed on record bases or permanent denture bases
to be used in recording jaw relations and for arranging
teeth.
Requirements :
the position should be in the anticipated position of the
artificial teeth.
it must be securely attached to the base.
the occlusal surface must be smooth and flat.
it should be contoured to support the lip and cheeks
accurately.
all the surfaces should be smooth.
Uses :
The occlusion rims are used :
 to establish the level of the occlusal plane.
 to establish the arch form.
 to record the maxillary mandibular relations.
 for arrangement of the teeth.
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Wax rims are smooth
and have a flat occlusal
surface. They are about
as wide buccolingually
as denture teeth – wider
in the posterior,
narrower in the anterior
The occlusal rim must
be centered
buccallingually over and
parallel to the residual
ridge crest.
The anterior portion of
the maxillary occlusal
rim is labially oriented
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The anterior wax rim
height is 22-mm on the
maxillary and 18-mm on
the mandibular arch.
The width of the anterior
rim is approximately 3to 4-mm thick.
The width of the occlusal
rim in the posterior
region is approximately
8- to 10-mm thick.
The occlusal rim is
properly sealed to the
baseplate without any
voids.
The posteriors of the
occlusion rims are cut at
a 30º angle to the occlusal
plane
The occlusal plane is defined as the average
plane established by the incisal and occlusal
surfaces of the teeth".
Importance of orientation of occlusal plane
 Anteriorly, occlusal plane mainly helps in
achieving esthetic & phonetic.
 posteriorly, it forms a milling surface, where
tongue & buccinator muscle are able to position
the food bolus onto it , and hold it there during
mastication.
Incorrect
of occlusal plane would hamper
esthetics, phonetics, & mastication. It may affect
stability of complete denture & ultimately result
in alveolar bone resorption.
Maxillomandibular relations is defined
as any spatial relationship of the maxillae
to the mandible ; any one of the infinite
relations of the mandible to the maxilla
(GPT 7).
An accurate determination,recording and transfer of jaw
relation record from edentulous patient to the articulator is
essential for restoration of function,facial apperance and
maintaince of patient health.
CLASSIFICATION:
Boucher classified jaw relations into three groups,
•
1. Orientation relations
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2. Vertical relations
•
3. Horizontal relations
ORIENTATION RELATION
Orient the mandible to the cranium in such a way that
when the mandible is kept in its most posterior
position, the mandible can rotate in a sagittal plane
around an imaginary transverse axis passing through
or near the condyles.
THE GLOSSARY OF PROSTHODONTIC TERMS , 7th EDITION ,
THE ACADEMY OF PROSTHODONTICS,1999.
THE AXIS CAN BE LOCATED BY THE FACEBOW.
ORIENTATION OF MAXILLA IN RELATION TO BASE OF SKULL
Plane of maxilla may be tilted in some patients , in such cases plane
of mandible will not be altered since it articulates with base of the skull. Hence , a
maxillary tilt will alter the relationship of maxilla to mandible during different
movements, also affect the level of occlusal plane .
A face bow is a caliper- like instrument used to record the spatial
relationship of the maxillary arch to some anatomic reference point or points
and then transfer this relationship to an articulator ;it orients the dental cast
in the same relationship to the opening axis of the articulator. (GPT 7)
 Customarily The Anatomic References Are The Mandibular Condyles
Transverse Horizontal Axis & Other Selected Anterior Reference Point.
 Also Called Hinge Bow .
ARMAMENTARIUM
DIAGRAMMATIC PRESENTATION
OF A FACE BOW
CONDYLE
EAR BOW : AN INSTRUMENT SIMILAR TO A FACE BOW THAT INDEXES TO
EXTERNAL AUDITORY MEATUS [EAM] & REGISTERS THE RELATION OF
MAXILLARY ARCH TO EAM & HORIZONTAL REFERENCE PLANE.PROVIDES
AN AVERAGE ANATOMIC DIMENSION BETWEEN EAM & HORIZONTAL AXIS
OF MANDIBLE.
THE GLOSSARY OF PROSTHODONTIC TERMS , 7th EDITION ,
THE ACADEMY OF PROSTHODONTICS,1999
The face bow helps to relate the jaws to the arc of closure or hinge axis of the
mandible. When this relation is transferred to the articulator ,it simulates some of
the jaw movements of the patient.
 Establishes the relationship between the maxillary
arch and the horizontal plane.
 Transfers this relationship to the articulator.
 Provides for an accurate mounting of the maxillary
cast to the articulator.
The missing teeth are restored by the CD,FPD,RPD to restore
function & esthetics .
It is essential to develop proper occlusion for maintaining health of
supporting structures orofacial musculature,TMJ.
So there is a need for accurately locating the hinge axis & recording &
transferring the same on to the articulator, to enable the accurate
reproduction of occlusal relationship on an articulator.
This is achieved by Face bow which records the position of jaws in
relation to the condylar mechanism & aids in transferring the same
relation onto the articulator.
Lazzari has listed the advantage for using the face bow1. It permits the more accurate use of lateral points for the arrangement
of the teeth .
2. It aids in securing the antero-posterior cast positioning with relation to
the condyles of the mandible .
3. It registers the horizontal relationships of the cast quite accurately and
thus assist in correctly locating the incisal plane.
4. It is an aid in the vertical positioning of the cast on the articulator.
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Failure to use the facebow can lead to errors in occlusion of the denture.
Occlusal error on full occlusal rims
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The errors would be negligible if all the interocclusal records were made precisely
at the occlusal vertical relation at which the occlusion was to be established and if
zero-degree teeth were used.
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If cusp teeth are used or if interocclusal records are made with the teeth out of
contact so that the vertical separation of the casts or dentures must be reduced on
the articulator, the face-bow record is essential.
 The Face bow transfer allows a more accurate arc of
closure on the articulator when the interocclusal
records are removed and the articulator is closed.
 Its use requires little time, and the convenience it
provides in the cast-mounting procedure saves that
time.
SO………Indications for the Use of Face-Bow
I.
II.
When balanced occlusion is desired in centric as well as eccentric positions.
When cusp form teeth are used. (Definite cusp fossa/cusp tip to cusp incline
relation is desired )
III.
When interocclusal check records are used for verification of jaw position
IV.
For constructing accurate crowns and bridges.
V.
In full mouth rehabilitation, when accurate occlusal restorations are to be
made.
VI.
When occlusal vertical dimension is to be changed during teeth setting.
VII.
For diagnostic mounting and treatment planning.
VIII.
In gnathological studies and treatment.
IX.
For making occlusal corrections after denture processing.
HINGE AXIS
 Also called as -
Terminal Hinge Axis
Transverse Hinge Axis
Transverse Horizontal Axis
 According to GPT 7 ;
HINGE AXIS is an imaginary line around which the mandible
may rotate within the sagittal plane.
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Terminal Hinge axis is a horizontal axis around which the condyles
rotate during opening and closing movement upto a range of 20-25 mm.
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Beyond this range there is translation.
TODAY WITH CHANGING CONCEPT OF CENTRIC
RELATION,VIZ. ANTEROSUPERIOR BRACING ,THE TERM TRANSVERSE
HORIZONTAL AXIS IS PREFERRED TO TERMINAL HINGE AXIS.
THE DISCREPANCY OF HINGE AXIS BETWEEN RUM POSITION &
ANTEROSUPERIOR POSITION IS 0.2 mm [HOBO]
True condylar rotation. 12º rotation with maximum incisal
separation of 22mm.
WHY TO RECORD AND TRANSFER HINGE AXIS?
OPENING & CLOSING MOVEMENTS OF MANDIBLE ARE REPRODUCED
ACCURATELY AS THE OPENING AXIS OF THE ARTICULATOR IS COINCEDENT WITH
HINGE AXIS OF PATIENT. THEREFORE, TEETH CONTACT EACH OTHER ON
THE ARTICULATOR IN THE SAME WAY AS THEY DO IN PATIENT’S MOUTH.
IT IS THE STARTING POINT OF LATERAL MOVEMENTS.
PERMITS VERTICAL DIMENSIONS TO BE CHANGED ON THE ARTICULATOR.
HELPFUL IN DIAGNOSIS & TREATMENT PLANNING OF MOUNTED STUDY CASTS.
Distance between External Auditory Meatus and Hinge axis
AMONG THE THREE COMMONLY RECOMMENDED
TRAGAL REFERENCES FOR ALA TRAGUS LINE ,
PARALLELISM TO OCCLUSAL PLANE WAS USUALLY SEEN
WHEN MIDDLE OF THE TRAGUS WAS TAKEN TO FORM ALA
TRAGUS PLANE .
AMONG THE SEVEN TRAGAL REFERENCES SELECTED
TO ORIENT THE ALA-TRAGUS PLANE TO OCCLUSAL
PLANE,PARALLELISM WAS SEEN WHEN TRAGAL
REFERENCE WAS BETWEEN SUPERIOR BORDER & MIDDLE
OF THE TRAGUS [41.5%].
INFERIOR BORDER SERVED AS A POOR REFERENCE[2.3%]
1.TRAGAL REFERENCES TO ESTABLISH TRAGUS – CANTHUS LINE TO
LOCATE ARBITRARY HINGE AXIS
AUTHOR
TRAGALREFERENCE
WINKLER
TOP OF TRAGUS
SWENSON
TOP OF TRAGUS
HEARTWELL & RAHN
MIDDLE OG TRAGUS
McGREGOR
APEX OF TRAGUS
SHALLHORN & BECK
POSTERIOR
MARGIN OFTRAGUS
BEYRON
CENRE OFTRAGUS
Reference points
 The maxillary cast in the articulator is the base line from which all
occlusal relationships starts, and it should be positioned in space by
three points.
 The plane is formed by two points located posterior to the maxillae
and one point located anterior to them.
The Anterior point of reference
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The selection of the ant. point of the triangular spatial plane determines which
plane in the head will become the plane of reference when the prosthesis is being
fabricated.
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In selecting the reference plane, the dentist should have knowledge of following
anterior points---
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1) ORBITALEin skull, orbitale is the lowest most point of the infraorbital rim. One orbitale &the
two posterior points that determine the horizontal axis of rotation will define axisorbital plane.
 Orbitale & the two posterior landmarks define the plane are transferred
from the patient to the articulator with the face-bow.
 The articulator must have an orbital indicator guide that is in the same
plane as the hinge axis of the articulator.
 The axis-orbital plane can be transferred to the articulator in another way,
the face-bow itself is raised to the axis-orbital plane on the patient.
 2) ORBITALE MINUS 7MM.
Because porion is a skull landmark, we uses the midpoint of the upper
border of the ext. auditory meatus as the posterior cranial landmark on
the patient & this post. Tissue landmark on the average lies 7 mm
superior to the horizontal axis.
To compensate this , mark the ant. Reference point 7 mm below orbitale
on the patient.
 3) NASION MINUS 23 MM
Nasion is the deepest part of the midline depression just below the level of
eyebrows.
The nasion guide of the Quick Mount face-bow used in Whip-Mix articulator
fits into this depression. this guide can be moved in and out but not up and
down, from its attachment to the face-bow crossbar.
The crossbar is located 23 mm below the midpoint of the nasion positioner.
Face-bow crossbar and not the nasion guide is the actual ant. reference
point locator .
 4) ALAE OF THE NOSE
The wax occlusion rim made parallel with Camper;s line is transferred to
the articulator with a face-bow. Its occlusal plane is made parellel
with the upper and lower articulator arms.
In this way ,the ala-axis plane and the tentative occlusal plane are
horizontal and become the planes of reference.
Posterior point of reference
STANDARD PROCEDURES FOLLOWED TO LOCATE ARBITRARY HINGE AXIS:
11-5 ARBITRARY HINGE AXIS LOCATION: SRIBBING A HORIZONTAL
FROM SUPERIOR NOTCH OF TRAGUS OF EAR TO OUTER CANTHUS OF
EYE.POINT MARKED 11mm ANTERIOR ON THE TRAGUS FROM WHICH A POINT 5mm
DOWN IS MARKED AT RIGHT ANGLE TO TRAGUS CANTHUS LINE TO LOCATE ARBITRARY
HINGE AXIS.
BEYRON’S POINT: 13mm ANTERIOR TO THE POSTERIOR MARGIN OF TRAGUS ON A
LINE FROM CENTER OF TRAGUS TO OUTER CANTHUS OF EYE.
Beyron’s point
LUNDEEN’S POINT: 13mm ANTERIOR TO TRAGUS ON
LINE FROM BASE OF TRAGUS TO OUTER CANTHUS OF EYE
SIMPSON’S POINT: 11 mm ANTERIOR TO SUPERIOR BORDER OF TRAGUS
ON CAMPER’S LINE.
WEINBERG’S POINT: 11-13 mm ANTERIOR ON A LINE DRAWN FROM
MIDDLE & POSTERIOR BOEDER OF TRAGUS.
ABDAL-HADI POINT-It is based on the high co relation between the width
profile of the face &X co-ordinate of kinematic point. Y = 9.5+0.95(X)
A constant distance
equal to 0.5 m was used above the line passing from center of the external
auditory meatus to canthus to locate the supero inferior position.
GYSI’S POINT: Gysi placed it 11-13 mm anterior to the upper third of the
tragus of the ear on a line extending from the upper margin of the external
auditory meatus to the outer canthus of the eye.
Gysi point
BERGSTROM’S POINT: 11mm ANTERIOR TO THE POSTERIOR MARGIN OF TRAGUS ON
A LINE PARALLEL TO & 7mm BELOW FRANKFORT HORIZONTAL PLANE.
BERGSTROM’S POINT
Arbitrary Hinge Axis
Accuracy %
Investigator
98.0
Schallhorn, Beyron,
Points
BEYRON’S POINT
Beck
GYSI’S POINT
40.0
Beck, Lauritzen and
Bodner
LUNDEEN’S POINT
33.0
Teteruck and
Lundeen
BERGSTROM’S
POINT
83.3
Beck
Ear axis
75.5
Teteruck and
Lundeen
A-Frankfurt Mandibular Plane Angle
Frankfurt horizontal plane
Mandibular plane
Camper’s or Bromell plane
Prosthetic plane
OR
P
12°
A
ANS
GO
ME
TYPES OF FACE BOW
ARBITRARY FACE BOW
KINEMATIC FACE BOW
facia type
ear piece type
hanau face bow[sring bow]
slidematic[denar]
twirl bow
whip mix
FACIA TYPE HANAU FACE BOW ATTACHED TO HANAU
ARTICULATOR
EAR BOW RECORD
CHOICE OF FACE BOW FOR RECORDING TRANSVERSE HINGE AXIS
DENTAL PROCEDURES SUCH AS EXTENSIVE RESTORATIVE PROCEDURES ,DIAGNOSIS OF
OCCLUSION IN TMJ DISORDERS ,DIAGNOSTIC WAX UP,SELECTIVE GRINDING,ect.,WHERE
PRECISION IS INDISPENSIBLE,TRANSVERSE HINGE AXIS LOCATION & TRANSFER IS
BENEFICIAL.
ARBITRARY FACE BOWS SUCH AS EAR PIECE FACE BOW & FACIA FACE BOW HAVE THEIR
OWN ACCURACY LIMITATIONS.
HOWEVER , A CORRECT ARBITRARY FACE BOW TRANSFER IS BETTER THAN AN
INACCURATE TIME CONSUMING HINGE AXIS RECORD.
“IN THE ABSENCE OF TRUE HINGE AXIS MOUNTING , ARBITRARY FACE
BOW SERVES THE PURPOSE,BUT TO A LESSER ACCURACY.”
ARBITRARY FACEBOWS:
a.
Make use of arbitrary or approximate points on the face as the
posterior reference points.
b.
The condyle rods are positioned on these points.
c.
Sufficient for the fabrication of complete dentures, fixed partial
and removable partial dentures.
d.
Small error in location while using an arbitrary facebow will have
only a negligible effect at the occlusal level.
e.
The resiliency and life effect of the oral tissues make the exact
transfer and location of the hinge axis unnecessary.
 FASCIA TYPE :

The earpiece face bow is converted to a fascia bow simply by
removing the earplugs.

Utilize posterior reference points on the skin over the
temporomandibular region.

Makes use of condylar rods instead of ear inserts.
A. HANAU FASCIA BOW
B. CLOSEUP OF THE CONDYLAR
ROD
EARPIECE TYPE :
 First described by DALBEY in 1914.
 Gained popularity during the 1960’s.
 Use the external auditory meatus (which has a fixed
relationship to the hinge axis) as the arbitrary posterior
point.
 Each earpiece has a central hole that connects to the
auditory pin on the articulator.

A rounded nylon earpiece is attached to the medial end of each scale.
HANAU EARPIECE TYPE

1. EAR INSERT CLOSEUP
2. COMPENSATOR
In articulators which do not have auditory pin, a condylar compensator
is needed. Special condylar compensators on the facebow or articulator
compensate for this by positioning the condylar inserts at a certain
distance behind the hinge axis of the articulator.

The earbow is simple to use.

Does not require measurements or marks on the face.

The accuracy is similar to other arbitrary methods.

The auditory pins are related to the articulators horizontal axis in
the same way the patients external auditory canals relate to the
patients horizontal axis.
KINEMATIC FACEBOW
1.
It is used to locate and transfer true
hinge axis.
2.
Complex instrument requiring the
fabrication of clutches which are
attached to the lower jaws.
3.
It requires more chair time .
4.
It also requires the use of articulators
with extendible condylar shafts (e.g.
Hanau H2X) which must be extended to
meet the stylus of the facebow.
 The kinematic face bow will locate the opening axis
physiologically with exceptional accuracy while the arbitrary face
bow is based on average computations of an axis of the jaw by
using anatomical landmarks.
 The kinematic face bow locates the rotational points by attaching to the
mandible . As the patient opens and close his mouth, a pointer is adjusted
until the axis of location is adjusted.
PARTS OF A FACEBOW
 U-Shaped frame
 Condyle rods
 Bite Fork
 Locking Device
 Orbital Pointer
Condyle rods
Orbital pointer
U-shaped frame
Locking clamp
Bite fork
U-Shaped frame
Two small metallic rods on either side of
the free end of the U-shaped frame that
contact the skin over the TMJ.
They help to locate the hinge axis or the
opening axis of TMJ and transfer the hinge
axis by attaching to the condylar shaft in
the articulator.
U-shaped frame
The face-bows that have a condylar rod to
record true hinge axis are called Kinematic
face-bows.
Some face-bows do not have condyle rods
instead they have an earpiece which fits
into the external auditory meatus. These
face-bows do not record the true hinge axis
and hence are called Arbitrary face-bow.
Condyle rods
Bite Fork
It is a U-shaped plate which is attached to the occlusal rim
while recording the orientation relation and it represents
the plane of maxilla.
Position the bitefork so that the midline mark of
the fork lines up with the patient’s midline
recorded on the rim
Orbital Pointer
It marks the anterior reference point (infraorbital notch) and is
present only in arbitrary face-bow.
ORBITAL
POINTER
THE EARPIECE FACE BOW
USES EXTERNAL AUDITORY MEATUS AS
POSTERIOR REFERNCE POINT
RELATIONSHIP OF EXTERNAL
AUDITORY CANALS TO HORIZONTAL
AXIS IS SUPPOSED TO BE CONSTANT
EAR PIECES ARE PLACED IN THE
EXTERNAL AUDITORY CANALS OF
PATIENT.
WHILE TRANSFERRING THE RECORD THE EAR PIECES ARE SEATED
ON THE AUDITORY PINS OF CENTRIC LOCKS.
AUDITORY PINS ARE RELATED TO ARTICULATOR’S HORIZONTAL
AXIS IN THE SAME WAY AS PATIENT’S AUDITORY CANALS RELATE TO
PATIENT’S HORIZONTAL AXIS.
PROCEDURE FOR FACEBOW TRANSFER
The bite fork is attached to the
upper occlusal rim. A variety of
techniques are available to attach it.
In one technique, the bite form is
heated and inserted into the labial
and buccal surfaces above the
occlusal plane.
BITE FORK IS ATTACHED TO THE OCCLUSAL RIM WITH
ALUWAX
 In another technique, the bite fork
is attached to the occlusal surface
with wax or impression compound.
PREPARING THE OCCLUSAL RIM TO
RECEIVE THE BITE FORK
The recording base is inserted into mouth, and extension rod of the bite fork is passed
through the locking device of the face bow.

The posterior reference point is measured and marked-13 mm anterior to the
tragus on the tragus-canthus line . When using the earbow this procedure is not
necessary.
The condylar rod is positioned on this mark (when using the earbow. The ear
insert is positioned in the external auditory meatus).
Condylar rods are moved from side to side until the readings are the same on both
sides.
Locknuts at the condylar rods are the tightened to suspend the face bow and bite fork is
secured to the assembly.
The instrument should be locked in the centric with the incisal pin flush with the upper
member.
The clamp holding the bite fork is also lockedgently first and then firmly
 The orbitale pointer when present is positioned so that its tip points
to the orbitale . All the locking nuts and clamps are secured.
 The whole assembly is then disengaged from the patients face. This is
done by loosening the condylar rods. The facebow assembly including
the bite fork with attached facebow is slipped off the patients face.
 The whole assembly (including occlusal rim) is then positioned in the
articulator. The condylar rods are locked on the hinge axis extensions
of the condylar analogs on the articulator,in the earpiece type.
 The condylar rod is positioned behind the articulator hinge axis to
compensate for the posterior position of the auditory meatus.
 A condylar compensator may be used in articulators which do not
have the auditory pin.

The position of the occlusal plane in the articulator is decided and the
facebow is raised or lowered accordingly ( using the elevating screw of the
facebow). Many use the midplane of the articulator as marked on the incisal
pin, whereas others adjust it according to the Frankfort plane ( the orbitale
pointer of the facebow is related to the orbitale indicator on the upper
member of the articulator.
The upper cast is attached to upper record base. The weight of the
occlusion rim and cast is supported with the help of a cast support
(also called mounting prop).
 The notches(indices) in the base of the cast are lightly lubricated. The
upper cast is then secured to the upper arm of the articulator with
plaster
 After the plaster sets, the facebow is disassembled. The articulator is
placed upside down. The lower occlusion rim is related to the upper
occlusion rim with the help of the centric relation record made earlier.
 The lower mounting is complete with mounting plaster.
 The articulator is now ready for customizing i.e. programming of the
condylar and incisal guidances.
OTHER METHODS OF RECORDING HINGE AXIS
• Pantograph– two face bows, one holds six recording tables
attached to the mandible & other with 6 styluses attached to the
maxillae.
• Transograph.
• Stereograph
• Computerized Axiograph
INACCURACY IN FACE BOW RECORDING AND CAST
MOUNTING
 There are several related factors –
1. Failure to locate the arbitrary hinge axis point of the
same place at each recording session.
2. Failure of the subjects to place the ear pieces of the
face bow in the external auditory meatus in their
proper places because the diameters of the EAM are
not the same for all individuals or even right to left in
same individual.
3. Failure to seat the maxillary teeth properly in the
occlusal index.
4. Failure to set the cast properly into the
occlusal index when mounting on the
articulator.
5. Cast support place in such away that the face
bow fork would be displaced.
6. The difference in stone expansion to
mount the cast on articulator.
7. Error occurring during measurement
procedures.