The document discusses orientation jaw relation and facebow transfer procedures. It defines orientation jaw relation as establishing the reference in the cranium and the relationship between the maxilla and mandible. It then describes recording orientation using a facebow to relate the maxillary cast to the articulator in the same way the maxilla relates to the temporomandibular joints. The document also summarizes the types of facebows, including arbitrary and kinematic, and procedures for using each in complete dentures and fixed prosthodontics.

1. ORIENTATION JAW RELATION
JAW RELATION:
Three dimensional spatial relationship of the maxillae to the mandible.
According to boucher, Jaw relations can be classified into :
1. Orientation
2. Vertical
3. Horizontal
Orientation relations establish the reference in the cranium. Vertical relation
establishes the amount of jaw separation allowable for the dentures.
Horizontal relations establish the front-to-back and side-to-side relationships
of one jaw to the other.
ORIENTAION JAW RELATION:
To record orientation jaw relation, mandible is kept in its most posterior position at
which it can rotate in the sagittal plane around an imaginary transverse axis passing through
or near the condyles.
This record gives the angulation of maxilla to the base of skull. The relation of
maxillary cast to the axis of rotation of the articulator must be the same relation that exists
between the maxillae and the terminal hinge axis in the skull. This is necessary in order to
develop on the articulator certain occlusal scheme that will need minimum adjustment in the
mouth.
Casts are mounted on the articulator with the maxillary cast preferably related to the
terminal hinge axis and the mandibular cast related to the maxillary cast by means of a
tentative centric relation record. Reproducing the horizontal axis is on the most important
steps because accuracy of all the other relationships depends on a correct starting poing. So it
is necessary to know first about terminal hinge axis or transverse horizontal axis.
It is important to note that it the relationship between the jaws and the axis of
movement, not an anatomical relationship between the jaws and the TMJ¶s.
HINGE AXIS:
An imaginary line around which the mandible may rotate within the sagittal plane
Terminal hinge axis:
An imaginary line around which the mandible may rotate within the sagittal plane in
the most retruded postion.
As the patient¶s jaw opens and closes, the posterior border of its movement, at least in
the earliest phases, is the arc of a circle in the sagittal plane around an imaginary transverse
axis passing through or near condyles. The same is true for articulator also. Similarly other

2. movement also occurs in arcs. For an accurate reproduction of those movements, the axes of
the those arcs should coinicide between patient and instrument, particulary when vertical
dimensions are to be changed.
Review of literature:
- Gray¶s anatomy - first described hinge like action in the lower compartment of
the temporomandibular joint.
- The importance of locating the transverse horizontal axis (THA) was first
expressed by Campion in 1905.
- 1921 ± McCollum, Stuart and others reported discovery of the first positive
method of locating the axis. He emphasized that the maxillary cast should be at
the same orientation on the articulator as the patient¶s maxillae was to the
temporomandibular joints.
- Brotman, Weinberg and Zuckerman demonstrated the importance of this axis
through mathematical models of occlusal errors that would result with deviations
from the THA of the patient.
- Wilkie also described the importance of the anterior reference point.
- Lauritzen and Wolford demonstrated varying degrees of accuracy in locating the
THA on patients in the range of 0.5 to 2 mm among skilled operators.
- Kurth and Feinstein Borgh and Posselt, Winstanley, and Bowley and Piercell
demonstrated the same magnitude of error on experimental model systems with a
known arc of closure but without patient-related variables. These studies have
emphasized that a certain amount of error would be expected because of operator-
and equipment-related variables.
- Snow ± recognized the importance of the hinge axis in mandibular movements
and developed a face-bow to be used to transfer the postion of the axis of the
articulator.
Significance:
- Learnable, repeatable and recordable position that co-incides with the position of
centric relation
- Condyles are in definitive postion in fossae during terminal hinge movements.
FACE-BOW:
Face bow is calliper like device used to record the relationship of the maxillae to the
temporomandibular joints.
The primary use of facebow is to mount the maxillary cast accurately on the
articulator. It uses 3 distrinct reference points (two posteriors and one anterior) to locate the
cast on the articulator. The posterior reference points are the hinge axis of each condyle and
anterior point is the arbitrary point.

3. Purpose :
y To orient the maxillary cast to the articulator in the same relationship to the opening
and closing axis of the articulator as exists between the maxillae and the opening and
closing axis in the temporomandibular joints.
y It also retains the cast in its correct relation until it is attached to the upper member
with plaster.
Review:
y 1880 ± Hayes used a tongue like device which is called ³calliper´. This instrument
was not used as the facebow is used today, but it did relate the edian incisal point to
its distance from the condyles.
y Gysi ± developed an instrument similar to a facebow primarily to record the paths of
the condyles. However, it was also used to transfer the maxillary cast to the
articulator.
y 1905 ± Campion was the first who felt that the axis of the articulator should coincide
with that of the patient.
y Snow ± introduced Snow face-bow. The majority of facebows used today are
modification of this. The snow type of facebow utilizes arbitrarily located marks on
the skin at the condyle points as the hinge axis position. So this is called arbitrary
face- bow. The condylar rods are adjusted to these points. There are no adjustments to
compensate for asymmetric hinge points either vertically or horizontally. Therefore, if
the terminal hinge rotational centers are to be located, a facebow capable of being
adjusted to any asymmetric location must be used.
y Preston presented various limitations and errors of the facebow transfer technique due
to both equipment and anatomic asymmetry. The occlusal errors that result from
deviations from the THA of the patient were shown to be due to the differences in the
arc of closure between the patient and the articulator.
Parts of facebow:
y U-shaped frame: It is large enough to extend from the region of one TMJ around
the front of the face (5 to 7.5 cm in front) to the other TMJ and wide enough to
avoid contacts with the sides of the face.
y Condylar rods: It is that part that contact the skin near the TMJ.
y Fork: it is that part that attaches to the occlusal rims. The fork attaches to the face
bow by means of a locking device, which also serves to support the facebow, the
maxillary occlusal rim and the maxillary cast while the cast are being attached to
the articulator. The fork of the arbitrary facebow is attached to the maxillary
occlusal rim, so the record is a simple relationship between the upper jaw and the
approximate axis of the jaw opening.
Indication:
y When cusped teeth are used which allows minor changes in the occlusal vertical
dimensions without having to make new maxillomandibular records

4. y Balanced occlusion in eccentric position is desired
y Definite cusp fossa or cusp tip to cusp incline relation is desired.
y Interocculsal check records are used for verification of jaw position.
y The occlusal vertical dimension is subject to change, and the alteration of tooth
occlusal surfaces are necessary to accommodate the change.
Different school of thoughts regarding use of facebow:
- When monoplane teeth are arranged on a plane in occlusal balance and the mandible
is in the most retruded relation to the maxillae at an acceptable vertical dimension of
jaw separation.
o It is questionable if one occlusal form of posterior tooth is indicated for all
edentulous patients.
o Electromyographic, laminographic, cinefluoroscopic ad mechanical methods
of studying the contacts of the occluding surfaces of the teeth and muscle
function indicate that teeth do make contact when the jaws are eccentrically
related.
- No alteration of the occluding surfaces of the teeth that would necessitate changes in
the vertical dimension of the occlusion originally recorded.
o Changes do occur in the vertical dimension of occlusion as a result of waxing,
flasking, processing, and mounting procedures. Resorption of the bone and
changes in the soft tissues that form the basal seat for the dentures alter the
vertical dimension of occlusion.
o The occluding surfaces of the teeth are alteredto correct for changes in the
vertical dimension of occlusion.
- No inter-occlusal check records that would be at a different vertical dimension from
that in the original interocclusal record.
o Dentists use inter-occlusal records check record to verify articulator mounting.
- When articulators that are not designed to accept a face-bow transfer are used in the
denture procedures.
o When an articulator with rotational centers that can be adjusted to conform to
the rotational centers of mandibular movements is used, the face-bow is an
accurate method of relating the casts to these centers.
o There is no scientific proof that the errors when the face-bow is not used are
within the acceptable physiologic range in all individuals.
Encountered errors when facebows are not used for orientation:
y Disharmony in centri occlusion.
y Anterior or posterior and/or superior or inferior to the axis when the vertical
dimensios recorded is not maintained.

5. y Below or posterior to the rotational centers so that the distal cusp inclines of the
mandibular teeth make premature contact with the mesial cusp inclines of the
maxillary teeth.
y Above and anterior to the rotational centers so that the mesial cusp inclines of the
mandibular teeth make premature contact with distal cusp inclines of the maxillary
teeth.
Types :
Facebow is of 2 types:
1. Kinematic
2. Arbitrary
Kinematic / hinge facebow :
The kinematic type of facebow is used to locate the terminal hinge axis and
transfer this record to the articulator when mounting the maxillary cast. This type of facebow
can be used on the articulator with a slight mechanical modification of the articulators.
Arbitrary face bow:
It is the one which is generally used in the construction of complete dentures
and is based on average computations of an axis opening of the jaw. It is simple to use and
relatively accurate.
Kinematic Arbitrary
Less accurate Accurate
Records true hinge axis Records hinge axis arbitrary using anatomic
average values.
Time consuming Less time consuming
Requires assembly to customized accordingly Self centering
Error of 1mm is expected Error of 5mm is expected
Doesn¶t use anterior reference point Uses anterior reference point for future
adjustments to the articulator.
Indication: Indications:
- Particularly when change in the - For all the complete denture
vertical dimesion of occlusion is procedures where change in vertical
made. dimensions at occlusion is not
significant.

6. STEPS IN FACEBOW TRANSFER PROCEDURE IN COMPLETE DENTURE:
1. PRELIMINARY STEP:
- Seat patient in comfortable position in the dental chair with backrest extending to
slightly below the scapula. The patient¶s head should be in upright position with the
headrest supporting the occiput.
2. LOCATION OF HINGE AXIS:
Can be done by two methods:
- Arbitrarily (with ear piece)
- By kinematic facebow
3. FACEBOW RECORDING
4. FACEBOW TRANSFER
5. MOUNTING OF THE FACE-BOW
6. ATTACHING OF THE CAST
ARBITRARY FACE-BOW:
In complete denture:
- Adjust the rims and retention and stability of the denture base is
checked.
- Attach fork to the modelling compound rims .
- Temper in water and seat the fork with rims into to the mouth
- Remove the fork from the mouth
- Chill it and check by keeping it on the cast
- Reseat the rims in the mouth.
- Ask the patient to grasp both arms of the facebow and guide the plastic
earpiece in the external auditory meatus.
- At the same time, the operator should slide the toggle onto the shaft of
the bite fork, making certain that toggle is postioned above the shaft.
- Tighten the 3 thumbscrew on the top of the face-bow.
- Adjust the anterior reference point and tighten the thumb screw.
- Transfer complete.
In Fixed Prosthodontics:
Anteriror reference point:
Anterior reference point such as inner canthus of the eye or a freckle or mole on the
skin is selected.
Facebow record:
- Add modelling compound/ hard base-plate wax to the facebow fork.

7. - Temper in water and seat the fork, making indetnations of the
maxillary cusp tips deep enough to be able to located on cast
- Remove the fork from the mouth
- Chill it and check by keeping it on the cast
- Reseat fork in mouth without distortion and ask patient to secure it
between arches.
- Ask the patient to grasp both arms of the facebow and guide the plastic
earpiece in the external auditory meatus.
- At the same time, the operator should slide the toggle onto the shaft of
the bite fork, making certain that toggle is postioned above the shaft.
- Tighten the 3 thumbscrew on the top of the face-bow.
- Adjust the anterior reference point and tighten the thumb screw.
- Transfer complete.
KINEMATIC FACE-BOW:
Hinge axis can be determined to be within 1mm. Kinematic facebow consists of 3
components:
- Transverse component
- Two adjustable side arms
In complete denture:
Hinge axis location:
- Make an accurate impression of the mandibular basal seat and pour an
accurate stone cast.
- On the cast make an accurate record base of self-curing or processed
acrylic resin.
- Attach cpmpound occlusal rims firmly to the record base and secure a
specifically designed bite fork to the rims, with the stem extending
forward parallel to the sagittal plane.
- Attach this assembly to the mandible with chin clamps or chin straps.
Note: movement between teeth and the clutch may produce inaccurate
styli rotaions.
Facebow transfer:
- Attach a hinge-bow to the stem and adjust the styli to the locations of
the condyles.
- The condyles are located by placing marks 13mm from the external
auditory meatus on a line from the outer canthus of the eye to the
superior border of the tragus of ear.

8. - Place the patient is semi supine position with headrest tilted slightly
backward.
- Assist or guide the patient in making hing openings and closings.
- When the rotational centers have been located and verified, secure the
styli.
- Place the patient in upright postion with the head unsupported.
- Move the styli to the side of the face and record with the dye. These
points should be tattooed.
In fixed prosthodontics:
Hinge axis recording:
1. A clutch , which is essentially a segmented impression traylike device, is attached
onto the mandibular teeth with a suitable rigid material such as impression plaster.
2. The transverse rod is attached to the transverse member that protrudes from the
patient¶s mouth.
3. The side arms are then attached to transverse member and adjusted so that the stule
are as close to the joint as possible.
4. Mandible is then manibpulated to produce terminal hinge movement. And the stylus
location are adjusted with thumbscrews until they make pure rotational movement.
5. When pure rotational movement is verified, the position of hinge axis is marked on
the patietnt¶s skin.
Facebow transfer:
1. An impression of the maxillary cusp tips is obtained in a suitable recording medium
on facebow fork.
2. The facebow is attached to the fork and arms are adjusted until the styli are aligned
with the hinge axis marks.
3. The facebow is then transferred to the articulator
PROCEDURE FOR DIFFERENT TYPES OF FACEBOW:
I. FOR HANAU FACE-BOW:
Arbitrary axis for hanau face-bow:
- Richey condylar marker is used to scrine an arc about 13mm anterior to the
external auditory meatus. Using a ruler, held so that it runs from the corners of the
eye to the top of the tragus of the ear, place a mark where this line intersects the
arc made by the condyle marker. This locates the arbitrary axis for the hanau face-

9. bow condyle rods, which is within 2mm of the true center of the opening axis of
the jaws.
- Plane of orientation can also be determined by the infraorbital notch as a third
point of reference with the infra-orbital pointer of the hanau face ±bow.
Face-bow transfer (hanau face-bow):
- The bite fork is heated and inserted in the maxillary rim parallel to the occlusal
plane.
- The recoding base is inserted into the mouth, and the extension rod of the bite fork
is passed through the locking device of the face-bow.
- The condylar rods are oriented over the arbitrary centers of rotation and moved
from side to side until the readings on the condyle rod scales are the same on both
sides while the crossbar os parallel to a line between the pupils of the eyes.
- The locknuts at the condylar rods are then tightened to suspend the face-bow, and
the bite fork is securely attached to the assembly.
- The condylar locknuts are then released, and the facebow and attached occlusal
rim are transferred to the articulator.
- The instrument should be locked in centric with the incisal pin flush with the
upper member.
- The condylar rods of the face-bow are inserted over the condylar ball extensions
and centered before being locked in position by tightening the locknuts.
- The face-bow is adjusted by the elevating screw to align the occlusal plane with
the groove marked around the halfway point of the incisal pin. A Hanau mounting
support or prop may be necessary to support the weight of the maxillary cast and
plaster during the mounting process.
II. FOR WHIP-MIX FACE-BOW:
Arbitrary axis for whip-mix face-bow:
- Locating an arbitrary axis is not necessary when using whip-mix articulator, since
it was designed and constructed after much research with a built-in-locator. The
insertion of plastic ear piece into the external auditory meatus automatically
locates the face-bow in the proper position.
Face-bow transfer (whip-mix face-bow):
- Attach the maxillary stabilized base to the bite fork.
- Insert in the mouth and have the patient hold it in place with both thumbs using
light pressure, or place the lower base in the mouth and close against the bite fork.
- The face-bow is carried to the patient¶s face, and the face-bow fork toggle
assembly is slipped onto the stem of the bow fork; the plastic earpieces are
inserted into the external auditory meatus and brought slightly forward.
- The nasion relator assembly is attached to the face-bow, the plastic nose piece
should rest on the nasion, and the face-bow is tightened.
- The face-bow is locked to the bite fork.

10. - The positioning of the face-bow and locking of the bite fork to the facebow must
be done carefully or the purpose of the face-bow transfer is defeated. The entire
assembly is then carried to the articulator.
- The upper cast is attached to the articulator.
- The proper use of the face-bow prevents errors of occlusion in the finished
dentures during eccentric movement of the lower jaw within the functional range.
III. FOR DENAR SLIDEMATIC FACEBOW:
Arbitrary axis for Denar Slidematic Facebow:
- It uses the external auditory meatus for determining the arbitrary hinge axis
location. A built-in reference pointer aligns the face-bow with the horizontal
reference plane. The anterior reference point is marked on the patient¶s right side
using the Denar Reference Plane Locator. The point is 43mm above the incisal
edge of the right central or lateral incisor for a dentulous patient. For an
edentulous patient this distance is measured up from the lower border of the upper
lip when the lips are relaxed.
Face-bow transfer (denar slidematic face-bow):
- The bite fork is heated and inserted into the maxillary occlusal rim parallel to the
occlusal plane with the patient¶s midline aligned with the index ring of the bite
fork.
- The facebow is assembled on the patient by inserting the stem of the bite fork into
the transfer jig as the ear piece is inserted into the external auditory meatus.
- The right and left arms of the face-bow are geared for equidistance movement
from its center.
- Lock screw on the face-bow is tightened and lock screw on the anterior reference
point is loosened.
- The face-bow is raised or lowered until the pointer is aligned precisely with the
anterior reference point.
- Clamps on the transfer jig are then tightened.
- The scale on the face-bow represents half the patient¶s intercondylar distance,
which is of value in setting articulators having an intercondylar distance
adjustment. The inter-condylar distance is recorded at this time.
- The lock-screw on the face-bow is loosened, and the bow is opened and removed
from the patient.
- The face-bow is detached from the bite fork assembly.
- The incisal table is removed from the articulator and the articulator index inserted
in its place.
- The transfer jig with the bite fork and maxillary occlusion rim attached is secured
in the articulator index prior to mounting the maxillary cast.
ATTACHING THE MAXILLARY CAST TO THE ARTICULATOR:
Several ways are available for attaching the maxillary cast to the articulator:

11. - Artic-U-Loc : consists of a striker plate embedded in the base of the
cast when it is poured, and a magnet that holds the cast to the
articulator. This makes a secure mounting without the use of a pin.
- Hanau split remounting plate: not as handy to use. The two parts are
held together by a pin. The Whip-mix remounting plate, suggested by
Dr. Samuel E. Guyer, provides a precise mounting and is easy to use.
A pin provides a means of retention.
- Notch method: Does not require any additional equipment. This has
disadvantage of requiring plaster or compound to reattach it to the
articulator should the cast come loose during any stage of the
procedure.
REFERENCES:
1. Sheldon winkler 2nd edition OF ESSENTIALSOF COMPLETE DENTURE
PROSTHESIS
2. Charles m. heartwell, Jr, urthur O. Rahn . Syllabus of complete denture 4th edition.
3. Zarb and Bolender 12th edition . Prosthodontic treatment of edentulous patient/.
4. Rosenstiel, land, Fujimoto. Contemporary fixed prosthodontics 3rd edition.
5. Shillinburg et al. Fundamentals of fixed prosthodontics 3rd edition.