horizontal jaw relation.pptx

AKANKSHA
JR II
DEPARTMENT OF PROSTHODONTICS AND CROWN & BRIDGE

HORIZONTAL
JAW
RELATION
Centric relation
Eccentric relation
Theories
Methods of
recording
Physiological
Functional
Graphic
Protrusive
Lateral
Clinical
outcome

“
Any spatial relationship of the mandible to the maxilla

HORIZONTAL JAW RELATION
It is the relationship of the mandible to the maxilla in a
horizontal plane
The relationship of the mandible to the maxilla in the
anteroposterior direction

It can be of two type
Centric relation
Eccentric relation Protrusive relation
Lateral relation

CENTRIC RELATION
The most retruded relation of the mandible to the maxilla
when the condyle are in the most posterior unstrained
position in the glenoid fossa from which lateral movements
can be made, at any given degree of jaw separation
GPT 1

CENTRIC RELATION
A maxillomandibular relationship, independent of tooth contact,
in which the condyles articulate in the anterior-superior position
against the posterior slopes of the articular eminences in this
position, the mandible is restricted to a purely rotary movement;
from this unstrained, physiologic, maxillomandibular relationship,
the patient can make vertical, lateral or protrusive movements; it
is a clinically useful, repeatable reference position
GPT 9

MUSCLES INVOLVED IN
CENTRIC RELATION
The masseter, temporalis and medial
pterygoid muscle connects the mandible
to the lateral pterygoid plate in such a
way as to act as the steering mechanism
for the mandible and helps in elevating
mandible to centric relation position

Significance of Centric Relation
Centric relation position acts as
a proprioceptive center to guide
the mandibular movements

Purpose of recording centric relation
 It is bone to bone relation and it is constant
 It is repeatable and recordable and thus serves as reliable guide
for developing centric occlusion in complete dentures
 It is related to terminal hinge axis

Purpose of recording centric relation
 Functional movements like chewing and swallowing can be
carried out since it is the most unstrained position.
 It is a definite entity, so used as reference point in establishing
centric occlusion
 It is more definite than vertical relation since it is independent of
tooth contact

Theories of centric relation
The muscle theory
The ligament theory
The osteofiber theory
The meniscus theory
Saizar P. Centric relation and condylar movement: anatomic mechanism. J Prosthet Dent. 1971 Dec;26(6):581-91.

The Muscle Theory
Defence reflex
External pterygoid
muscles contract
Halts the joint

The Ligament Theory
Ligaments binds element of
articulation, limit the
possibilities of movement and
are also capable of determining
terminal border position

The Osteofiber Theory
Involves a retrusive terminal
stop formed by soft tissues of
posterior part of glenoid fossa
Fibrous stop act as buffer

The Meniscus Theory
The posterosuperior surface
unfolds along the roof of
the glenoid fossa

The Meniscus Theory
Disc with their retro meniscal fibrous
tissues- stop the retrusive condylar
movements

Factors influencing
centric relation records
Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous mouths. 1964. J Prosthet Dent. 2005;93(4):305-310.

The resiliency of the supporting tissues
Stability of the recording bases
Temporomandibular joint and associated neuromuscular mechanisms
Pressure applied in making the recording
The technique used in making the recording and the recording devices
used
Skill of the dentist

The health and cooperation of the patient
The maxillomandibular relationship
Posture of the patient
Character and size of residual alveolar arch
The amount and character of saliva
Size and position of tongue

Retruding the mandible
• Difficulties in Retruding mandible
• Methods of Retruding the mandible

Difficulties in obtaining mandibular retrusion
Biological
Psychological
Mechanical

Biological
 Lack of muscle coordination
 Lack of synchronization between the protruding and
Retruding muscles due to HABITUAL eccentric jaw
positions

Psychological
 Involves patient and dentist
 Inability of the patient to follow
dentist’s instructions

Mechanical
It is essential that the record bases on which the centric relation
are made, fit perfectly and not interfere with each other
Poorly fitting baseplates

Methods to retrude the mandible while recording centric relation
Relaxation of Jaw
Simplest, easiest and most efficient way of causing retrusion
by verbal instructions to the patient
Instruct the patient by saying “ Let your lower jaw relax, pull it
back, and close on your back teeth”

Pushing Upper Jaw
Patient is instructed to “Get the feeling of pushing your upper
jaw out and close your back teeth together”
By getting the feeling of pushing the upper jaw forward, they
automatically pull the lower jaw backward.

Stretch and Relax Movements
Patient is instructed to protrude and
retrude the mandible. Dentist can aid
by a slight pressure on the point of the
chin

Retrusion of Tongue
 Patient is instructed to keep the tip of tongue in contact with posterior border of
the maxillary record base and then patient is asked to close until the rims come
into contact
Bissasu M. Use of the tongue for recording centric relation for edentulous patients. J Prosthet Dent. 1999;82(3):369-370.

Rapid Tapping of the Occlusal Rims
 Gentle tapping of occlusal rims rapidly and repeatedly retrudes the mandible

Head Position
 Tilting the head backwards results in retrusion of the mandible as this
will place tension on the infra-mandibular muscles and tend to pull the
mandible to a retruded position

Swallowing and Temporalis muscle check
 Swallowing usually brings the mandible in a retruded position
 The temporalis muscle show reduced function when the mandible is in
protruded position. So its contraction can be felt when the mandible is
in or near retruded position by placing finger tips on each side of the
head

Recording Centric Relation
• Minimum pressure technique
• Heavy pressure technique

Minimum closing pressure
 The record should be made with minimal closing pressures so the
tissues supporting the bases will not be displaced while record is
being made.
 Objective : For the opposing teeth to touch uniformly and
simultaneously at their first contact

Heavy closing pressure
 The record should be made under heavy closing pressure so that
record bases will be displaced while the record is being made.
 Objective : To produce the same displacement of the soft tissues as
would exist when heavy closing pressure were applied to denture

Methods of Recording Centric Relation

Boucher
Static methods
Functional
methods
Interocclusal records with/without
central bearing devices and tracing
devices
Chew in technique :
• NeedlesHouse technique
• Patterson technique

Physiological
methods
Functional
methods
Graphic methods
Radiographic
method
Tactile method /
Interocclusal check records
Chew in technique :
• Needles House technique
• Intraoral devices
• Extraoral devices

The
proprioceptive
impulses of
the patient
Kinesthetic
sense of
mandibular
movement
The visual
acuity and
sense of touch
of the dentist
No pressure is
exerted on the
interocclusal
record

Tactile sense or Interocclusal
check record method

Commonly used materials
Waxes
Impression compound
Zinc oxide eugenol paste
Impression plaster
Additional silicone
Polyether
usually preferred because they offer
uniform resistance to pressure

Tentative jaw relation
Maxillary occlusal rim is inserted into patients
mouth
Vertical dimension at rest is established
Tentative centric relation is recorded by
Retruding the mandible
Occlusal rims articulated and artificial teeth
arranged
Trial dentures ready for making interocclusal
check record

Making inter-occlusal check record
The trial dentures are removed and the wax is allowed to cool
Aluwax is loaded onto the occlusal surface of teeth in the mandibular occlusal rim
The patient is asked to slowly retrude the mandible and close on the was till tooth contact occurs
The upper and lower trial dentures are inserted into patients mouth
Artificial teeth are prevented from contacting the opposing members by keeping a piece of cotton inter-occlusally

Making inter-occlusal check record

Factors affecting the success of interocclusal record method
Uniform consistency of the recording material.
Accurate vertical jaw relation records.
Stability and fit of the record base.
Presence of reference points embedded in the record like
metal pins or styli.

Static or Pressureless Method
The occlusal rims are customized as usual and the patient is trained to close at
centric relation position. Once the patient attains the centric relation position,
the denture bases with occlusal rims are indexed/sealed in this position
Nick and Notch
method
Stapler Pin
method

Nick and Notch method
• Most commonly used method of indexing the centric record
• Final centric jaw relation is carried out after establishing a
proper vertical jaw relation
• No occlusal check record is performed during try-in

The patient is seated in an upright position
Up to 3 mm of wax is removed on either side of the
mandibular occlusal rim from the premolar region
till the distal end. This depression created on the
occlusal rim due to removal of wax is called trough

One or two notches are cut on the
corresponding area on the maxillary occlusal
rim. The notch resembles a "V“ shaped valley
running totally across the width of the occlusal
rim
One nick is cut anterior to the notch. This is also
a "V“ shaped valley but it does not extend
throughout the width of the occlusal rim

the nick and notch on maxillary occlusal rim are
lubricated with petroleum jelly
The prepared occlusal rims are inserted into the
patient’s mouth and the patient is taught to close
his mandible in centric position
Mandibular occlusal rim removed from the
mouth
Bite registration material is placed in the trough
created in the mandibular occlusal rim

The mandibular occlusal rim is placed back in
patient’s mouth and patient is asked to close in
centric relation
The mouth should close such that the anterior parts
of the occlusal rim almost touch but not press
against it
Both the rims are removed, cooled and excess
material is trimmed

Stapler pin method
• In this method, after recording the
centric relation, the occlusal rims are
indexed using a bunch of stapler pin.
• The method is not preferred as centric
relation record cannot be verified

Pressure Method
• After establishing the vertical dimension, the maxillary occlusal rim is inserted
into patient’s mouth
• The mandibular rim is fabricated excess of height
• The entire mandibular rim is softened in water bath and inserted into
patient’s mouth
• Patient is guided to close in centric relation and asked to close on soft wax
• After patient closes mouth till the predetermined vertical dimension, both
rims are removed , cooled and articulated

Shanahan technique
The cones made up of soft wax were mounted on the mandibular
occlusal rim
Patient was advised to make swallowing movements several times,
while the tongue would force the mandible into its centric relation
position
The cones of soft wax were moulded during these movements
Shetty, Manoj & Shetty, Ganaraj. (2020). Comparative Evaluation of Various Techniques to Record Centric Relation- A Literature Review. Journal of Evolution
of Medical and Dental Sciences. 09. 53-59. 10.14260/jemds/2020/12.

FUNCTIONAL METHODS
• Needles House technique

• Utilizes the functional movements to record the
centric relation
• Patient is asked to perform border movements such
as protrusive and excursive movements , in order to
identify the most retruded position of mandible

Factors common to all functional methods
Tentative centric relation and vertical
dimension are measured for determining an
accurate centric relation
Occlusal rims are reduced in excess than that
required for tentative vertical dimension
Exact vertical dimension at occlusion is
determined only when the patient closes on
the occlusal rims and their attachments
Needles House
Patterson
Meyer

Disadvantages
Inaccuracy can result from:
• Displaceable basal seat tissues
• Resistance of recording mediums
• Lack of equalized pressures
Patients must have very good neuromuscular coordination and
be capable of following instructions

Needleshouse Method
Involves fabrication of occlusal rims
made from impression compound
4 metal beads or styli are embedded
into premolar and molar areas of
maxillary occlusal rim

Patterson Method
Involves fabrication of occlusal rims
made from modelling wax
Trench or trough is made along the
length of mandibular occlusal rim

Movements will produce compensating curves on the plaster carborundum mix

As these movements are made, the height of the plaster carborundum mix
is also reduced.
The patient is asked to continue these movements till a predetermined
vertical dimension is obtained.
Finally the patient is asked to retrude his jaw and the occlusal rims are
fixed in this position with metal staples.

Meyer method ( modified functional technique )
Soft wax was utilized to make occlusal rims
The occlusal surface of the wax was coated with tinfoil
Mandible was guided to perform functional movement and
later plaster index was made on wax rims.
Plaster index was used as a guide to set the teeth
Shetty, Manoj & Shetty, Ganaraj. (2020). Comparative Evaluation of Various Techniques to Record Centric Relation- A Literature Review. Journal of Evolution
of Medical and Dental Sciences. 09. 53-59. 10.14260/jemds/2020/12.

Uses graphs or tracings to record the centric jaw relation
Graphic
methods
Arrow point
tracing
Measured along
a single plane
Pantograph
Measured three-
dimensionally

Arrow point tracing , Needle point tracing
Gothic Arch Tracing

Why “ Gothic Arch “ ?
Arrow point tracing was first proposed by Hesse 1897,
and later popularized by Gysi, 1908

Historical review of graphical recordings
Balkwill (1866)
• Earliest graphic recordings based on mandibular movements
• The intersection of the arcs produced by the right and left
condyles formed the apex of what is known as the Gothic
arch tracing.
Myers ML. Centric relation records-historical review. J Prosthet Dent.
1982;47(2):141-145

Gysi (1910)
• Extraoral incisal tracer on maxillary rim traced onto the
tracing plate, coated with wax attached with mandibular rim
• The rims were made of modeling compound to maintain the
vertical dimension of occlusion
1982;47(2):141-145

Sears
• Used lubricated rims for easier movement.
• He placed the needle point tracer on the mandibular rim and the plate
on the maxillary rim.
• He believed this made the angle of the tracing more acute and more
easily discernible. He would then cement the rims together for
removal.
1982;47(2):141-145

Phillips
• Recognized that any lateral movements of the jaw would cause
interference of the rims which could result in distorted record.
• Developed a plate for the upper rim and a tripoded ball bearing
mounted on a jackscrew for the lower rim
“Central Bearing Point “
This innovation supposedly produced equalization of pressure on the
edentulous ridge
1982;47(2):141-145

Stansbery (1929)
• Used a curved plate corresponding to monson’s curve mounted on
upper rim. A central bearing screw was attached to lower plate with a
3inch radius curve. After extraoral tracing , plaster was used to form a
biconcave centric registration
1982;47(2):141-145

Silverman
• Used an intraoral gothic arch tracer to locate the “biting point” of the
patient.
• The patient was asked to bite on hard tracing plate. This developed a
functional resultant of the closing muscles which would retrude the
mandible.
• The indentation made by the patient would be used for centric record
whether it corresponds to gothic apex or not
1982;47(2):141-145

Arrow point tracing
The pattern obtained on the horizontal plate with
a central bearing tracing device

Concept of arrow point tracing
The concept consists of attaching a stylus (a writing
device with a pointed end) to one occlusal rim and a
plate to the other rim.
The stylus traces or marks the path in the plate as
the mandible performs excursive movements from
the centric position.
The tracing is typically in the shape of a ‘gothic arch’
or ‘arrow head’ if the patient is trained to move the
mandible from centric to protrusive, right and left
lateral positions

Central bearing tracing device
A device that provides a central point of bearing or
support between the maxillary and mandibular dental
arches. It consists of a contacting point attached to
one dental arch and a plate attached to the opposing
dental arch. The plate provides the surface on which
the bearing point rests or moves and on which the
tracing of the mandibular movement is recorded. It
may be used to distribute the occlusal forces evenly
during jaw relation and/or for the correction of
disharmonious occlusal contacts.

Central bearing point
The contact point of central bearing device

Triangular plate of metal with extensions provided to attach
itself to the occlusal rim
In the center of the triangle a metal pointer is present

Central bearing plate
It is also a triangular piece of metal with extensions at the
three corners provided to attach the plate to the occlusal rim

Components
Tracers
Extraoral Intraoral

Gothic arch tracing
Advantages
• Most accurate method of
recording CR
• Allows equalisation of
pressure on supporting tissues
• Easy verifiable
• Can also be used to record
eccentric relations
Disadvantages
• May be difficult to locate the
centre of the arches
• More time consuming
• Training patient in making
mandibular movements is
strenuous

Important factors in graphical recordings
 Displacement of the record bases may result from pressure if the central
bearing point is off center, when the mandible moves into eccentric
relations to the maxillae
 If a central bearing device is not used, the occlusion rims offer more
resistance to horizontal movements
 It is difficult to locate the center of the true arches to centralize the
forces with a central bearing device when the jaws are in favorable
relation and far more difficult if the jaws are in excessive protrusive or
retrusive relation.
Bansal S, Palaskar J. Critical evaluation of various methods of recording centric jaw
relation. J Indian Prosthodont Soc 2008;8:185-9

 It is difficult to stabilize a record base against horizontal force on
residual ridge that have no vertical height.
 It is difficult to stabilize a record base against horizontal forces on
tissues that are pendulous or otherwise easily displaceable.
 It is difficult to stabilize a record base or bearing device with patients
who have large awkward tongues.

 Recording devices are not usually considered compatible with normal
physiologic simulation in mandibular movement.
 The tracing is not acceptable unless a pointed apex is developed, a blunt
apex usually indicates an acquired functional relationship and a sharp
apex usually indicates the position of centric relation.
 Double tracings usually indicate lack of coordinated movements or
recordings at a different vertical dimension of jaw separation. In either
event, additional tracings are necessary

 A graphic tracing to determine Centric Relation is made at the
predetermined vertical dimension of occlusion. This harmonizes Centric
Relation with centric occlusion and the antero-posterior bone to bone
relation with the tooth-to-tooth contact
 Graphic methods can record eccentric relations of the mandible to the
maxillae.
 Graphic methods are the most accurate visual means of making a
Centric Relation record with mechanical instruments; however, all
graphic tracings are not necessarily accurate

Indications
 Broad edentulous sides
 Adequate interarch space
 In patients with habitual centric (a more anterior position of
the jaws due to prolonged edentulous period without tooth
replacement), the use of the graphic method eliminates all
occlusal contacts on the rims, thus breaking the neuromuscular
reflex and allows the patient to record his true centric

Contraindications
 Severely resorbed ridges and excessively flabby ridges as they
lead to instability of denture bases
 Decreased interarch space – difficult to place central bearing
device without raising the vertical dimension
 TMJ arthropathy
 Abnormal jaw relations

In 1927, Hanau conceded that the Gysi tracing was satisfactory to check records,
but that universal usage was not good
Tech stated that the Gysi tracing technique was the only means that should be
used for centric records, all other methods were “mere deceptions and playthings”.
Kingery pointed out several drawbacks in the use of the central bearing point and
added that the “central bearing point allows for no control over the amount of
closing pressure applied by the patient.”

Kapur and A. Albert Yurkstas told that intraoral tracing procedure and
extraoral tracing procedure were more consistent as compared to wax
registration method
Phillips pointed to various errors produced by GYSI’s technique and
stated that, “if one occlusal rim is allowed to touch the other during the
lateral extreme positions, undue pressure is bound to be exerted on the
contact side, and on account of resiliency of the underlying tissues the
side not in contact will be unseated just enough to cause a false
reading for the horizontal inclination of the condylar path”.

A. Albert Yurkstas, and Krishan K. Kapur. Factors influencing centric relation records in
edentulous mouths., Journal of Prosthetic Dentistry 1957
Trapozzano stated “the use of the central bearing point is based on the
fallacious assumption that the central bearing point will produce
equalization of pressure.
Trapozzano maintained that the wax recording method was the most
accurate method because of the greater ability to equalize or centralize
pressure with this technique.

Intraoral tracing devices
and tracing procedure

Coble balancer
The central bearing pin is a
small cylinder attached to
maxillary denture base
The central bearing plate is
narrow and is designed like a
bridge across lower occlusal
rim

Condylator
The central bearing pin is
attached to mandibular
occlusal rim
The central bearing plate is
trapezoidal in shape

Ballard intraoral tracer
The tracing pin is attached to
mandibular rim and plate to
maxillary rim
• Palatal bearing plate
• Rounded head of correlator
pin
• Tension spring
• Mounting plate
• Pointed end of correlator pin

Swiss dent ball bearing bite recorder
The central bearing
point is a ball with a
single point of
contact .
The ball add weight
and stability to the
tracer

Microtracer
It is a circular tracer with
a semi-circular central
bearing point.
It is more comfortable for
the patient

Procedure for intraoral tracing
 The record bases attached to tracing point and plate are inserted
into patients mouth
 The central bearing point is adjusted such that it contacts the plate
at predetermined vertical dimension

 The patient is asked to make
anteroposterior and lateral
movements. While making these
movements, the central bearing
point will draw the tracing pattern on
the plate

 When the patient closes the
mouth, the central bearing
point contacts the metal
plate

Extraoral tracing devices
and tracing procedure

Hight tracer
The Hight tracer has an upper
tracing pin and a lower recording
plate. These tracers have ‘toothed’
extensions which are used to
attach the tracers to the side of the
occlusal rims

Sears tracer
It is a central bearing point tracer with
two tracing apparatus. It produces two
tracing simultaneously.
It is the only extra oral tracer which has
the tracing pin attached to the mandible
and the plate attached to the maxilla

Phillips extraoral tracer
Extraoral device with two tracing
apparatus
The tracing pin is attached to the
maxilla and the tracing plate is
attached to the mandible

Procedure for extraoral tracing
 The maxillary cast is mounted on the articulator with
face bow transfer
 The mandibular cast is oriented to the maxillary cast at
the established vertical dimension with a static CR record
 The condylar elements of the articulator are secured
against the centric stops

The central bearing and
tracing devices are mounted
on the respective rims

 The patient is seated with
head upright, and record
bases with attached devices
are inserted into patients
mouth.
 Record bases are checked for
stability, contact during
movements and interferences

 The stylus is retracted and patient
is trained to make various excursive
movements passively and actively
(if needed). Patient is instructed to
move the jaw forwards, right and
left from centric position.
Ney Excursion Guide

 When the patient is well trained in making
the movements, the recording plate is
coated with a thin coating of lacquer,
precipitated chalk or dark coloured wax
 The stylus is made to contact the recording
plate and the patient is instructed to make
the specific movements.

 When an acceptable tracing is made with a single sharp apex, a centric
record is obtained
 The rims and tracing are prepared to receive the centric record

Before making the records,
the undercuts are blocked
with wax and orientation
grooves made in the wax.

 The patient is instructed to retrude the
mandible such that the stylus contacts
the apex of the tracing
 Quick setting plaster is injected between
the rims and allowed to harden; thus, the
centric record is obtained

The occlusal rims are seated over
the casts and with the centric
record in place, and the mandibular
cast is remounted with the new
record.

Gerbers classification of arrow point tracing
Well defined apex with a symmetrical left and
right lateral component.
The mean gothic arch angle is about 120 degrees.
It reflects healthy TMJ without interferences in
condylar path and balanced muscle guidance
Typical

Similar to typical form except that it has more
obtuse left and right lateral tracings
The gothic arch angle is more than 120 degrees.
It signifies marked lateral movement of condyle in
the fossa.
Flat form

The tracing should be repeated till a defined
arrow point head is obtained.
Patient training is necessary
Round form / apex absent

Similar to typical form, however the extension
of tracing is very limited.
This can be due to restricted mandibular
movements, improper seating of denture
bases and painful fitting denture bases.
It is also an indication of long period of
edentulousness with an inhibition in condylar
movements
Miniature arrow point

It is a record of habitual and retruded centric
relation
Also seen when vertical dimension is altered
during registration
Double arrow point

The protrusive path of mandibular movement
extended beyond the apex of the Gothic arch.
This signifies a forced strained retrusive
movement of lower jaw either by patient or
operator.
It is also seen when the patient head is tilted
too far posteriorly
Dorsally extended arrow point

It is break or loss of continuity of lateral insical
path of gothic arch
This happens due to posterior interferences at
the heels of the denture base
Interrupted arrow point

The left and right lateral tracings meet in an
arrow point; however, the inclination to the
protrusive movement obtained is not
symmetrical.
This form of tracing indicates an error or
interference in forwarding movement of the
condyle.
Asymmetrical arrow point

Pantographic tracing
A graphic record of mandibular movement
usually recorded in the horizontal, sagittal
and frontal planes as registered by styli on
the recording tables of a pantograph or by
means of electronic sensors
Pantogram

Pantograph
An instrument used to graphically record in, one or more planes,
paths of mandibular movement and to provide information for the
programming of an articulator

It resembles a complicated
facebow
The surface over which the
tracing is done is called a “
flag “
A stylus (tracing pointer) is
present for each flag and it
draws tracing patterns on
the flags

CEPHALOMETRIC RADIOGRAPHS
Pyott and Schaeffer used cephalometric
radiographs to record centric relation and
vertical dimension of occlusion
However this method never gained
widespread due to errors in recording
centric relation

Conclusion
 Recording of centric relation is the most important factor in
dentistry. It is a very critical step.
 Therefore, it is recommended to discuss regarding various
methods and material aspects used in recording centric relation
more precisely.
 Skills of the operator and patient’s good neuromuscular
coordination are probably the most important factors in securing
an accurate Centric Relation record.

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