Horizontal Jaw Relation

HORIZONTAL JAW
RELATION
PRESENTED BY:
Dr. Anshul Sahu
MDS 1ST Year

CONTENTS:
 Introduction
 Centric Jaw Relation
 Definitions
 Chronological changes of definitions of centric relation
 Review of literature
 Features of Centric Jaw Relation
 Criteria for Centric Relation
 TMJ Socket Design
 Role of Musculature
 Centric relation in loading position
 Complication in recording Centric Relation
 Errors in Centric Relation
 Factors Influencing Centric Relation Records

 Centric relation and centric occlusion
 Recording Centric Jaw Relation
 Eccentric Jaw Relation
 Summary
 Conclusion
 References

INTRODUCTION
The principles of good occlusion apply to both
dentulous & edentulous patients. The problem is,
however, that there is no accordance on the definition
of good occlusion. It also is most probable that the
requirements of the occlusion for complete denture
differ from those of a natural dentition. For stability of
complete dentures to be maintained, the opposing
teeth must meet evenly on both sides of the dental
arch when the teeth contact anywhere within the
normal functional range of mandibular movement .

The human mandible can be related to the maxilla in
several positions in the horizontal plane. Among these
centric relation is a significant position, because of its
usefulness in relating the dentulous and edentulous
mandible to maxilla, where the teeth , muscles and
temporomandibular joint function in harmony. It is a
position of occluso-articular harmony.

JAW RELATION
Any spartial relationship of the mandible to the maxilla.
(GPT 8)
Jaw relation is recorded to measure the extensibility and
movements permissible by the patients
Temporomandibular joint.
3 DIFFERENT TYPES:
Orientation jaw relation
Vertical jaw relation
Horizontal jaw relation

 Horizontal jaw relation is the maxillomandibular
relation in a horizontal plane.
 Described as relationship of mandible to maxilla in the
anteroposterior direction.
 2 TYPES:
1) Centric Jaw Relation
2) Eccentric Jaw Relation:
- Protrusive relation
- Lateral relation: Left lateral; Right Lateral
 The basic horizontal relationship is centric relation. It is
a reference relationship that must be recognized in any
prosthodontic treatment.
Other horizontal relationships are deviations occurring
from centric relation, they are collectively referred as
eccentric relation

Definition:
The maxillomandibular relationship in which the condyles
articulate with the thinnest avascular portion of their
respective discs with the complex in the anterior-superior
position against the slopes of the articular eminences. This
position is independent of tooth contact. This position is
clinically discernible when the mandible is directed superior
and anteriorly. It is restricted to a purely rotary movement
about the transverse horizontal axis”
(GPT8)

According to GPT 1:
The most retruded relation of mandible to maxilla when the
condyles are in the most posterior unstrained position in the
glenoid fossae from which lateral movement can be made at
any given degree of jaw separation.
According to GPT 3:
The most retruded physiologic relation of the mandible to the
maxilla to and from which the individual can make lateral
movements. It is a condition that can exist at various degree
of jaw separation . It occurs around the terminal hinge axis.
According to GPT 4:
The jaw relation when the condyles are in the most posterior,
unstrained position in the glenoid fossa at any given degree
of jaw separation from which the lateral movements can be
made.

According to GPT 5:
The maxillomandibular relationship in which the condyle
articulate with the thinnest avascular portion of their
respective disks with the complex in the anterior – superior
position against the shapes of the articular eminences.
Boucher defines as:
The most posterior relation of the lower to the upper jaw from
which lateral movements can be made at a given vertical
dimension.
It is the maxilla to the mandible relation in which the condyles
and disks are thought to be in the midmost, uppermost
position.

According to Ramsford:
A clinically determined position of the mandible placing both
condyles into their anterior uppermost position . This can be
determined in patient without pain or derangement in the
TMJ.
According to Lang:
The relation of the mandible to the maxilla when the
condyles are in the upper most and the rearmost position in
the glenoid fossae . The position may not be recorded in the
presence of dysfunction of the masticatory system.

The Glossary Of Occlusal Terms, International Academy
Of Gnathology 1979:
The relation of mandible to maxilla when condyle are in their
rearmost, uppermost, midmost position in the glenoid fossa
Centric relation can exist over a range of jaw opening and is
not violated until the condyle leave their posterior positions in
the glenoid fossae, the unstrained hinge position of the
mandible .
According to Moyers:
Centric relation is the position of the mandible as determined
by the neuromuscular reflex first learned for controlling the
mandibular position when the primary teeth were in
occlusion.

According to Dawson:
CR is the relationship of the maxilla to the mandible when
the properly aligned condyle disc assembly are in the most
superior position against the eminentiae irrespective of
vertical dimension or tooth position.
At the most superior position, the condyle disc assemblies
are braced medially, thus CR is also the midmost position.
A properly aligned condyle disk assembly in CR can resist
max loading by the elevator muscles with no sign of
discomfort.

CHRONOLOGICAL CHANGES OF DEFINITIONS
OF CENTRIC RELATION
Mc Collum(1920):
Rearmost condylar position.
He showed that the condyle had a pure rotational movement
when the operator guided the mandible in the most retruded
position in the glenoid fossa . He was the first to name this
position as centric relation
Granger (1952):
Upmost, rearmost position .
A second component namely a most superior position was
considered necessary for bracing since the condyle was
unstable when it was only in the most posterior position

Stuart (1969):
Rearmost ,uppermost, midmost condylar position-(RUM)
position
A medial component was added for a stable condylar
position (three – dimensional position ). It was considered a
physiological condylar position harmonious with centric
occlusion . RUM position was later accepted by the
International Academy of Gnathology.
American Equilibrium Society (1977):
It challenged RUM position as it was considered to give
pressure on the retrodiscal tissue at bilaminar zone and
proposed the most anterior and upper most position of
condyle opposite the slope of articular eminentia.

Celenza (1978):
Stated that condyle disk assembly braced superiorly and
anteriorly against the posterior slope of articular eminence .
American equilibration society (1987):
They revised their previous definition and believed that the
condyle articulate with the thinnest avascular portion of the
disc in the anterior ,most superior position of the dorsal slope
of eminence.

REVIEW OF LITERATURE
Physiologic Jaw Relations And Occlusion Of Complete
Dentures. Shanahan JPD;1955;5;319-324
 He stated the constant function of swallowing saliva is the
basis for establishing the mandibular positions and
occlusion.
 In swallowing saliva, the mandible rises to its habitual closing
terminal, then, as the saliva is swallowed mandible is forced
backwards into the pharynx by the tongue, thus retruded to
its physiological centric relation.

The hinge axis and its practical application in the
determination of centric relation. Cohen
;jpd;1960;10;248
 The center of meniscus is devoid of blood vessels and
nerves and is pressure bearing. Due to this fact every joint
has a degree of tolerance which permit the condyle to be out
of its ideal position in final closure of mandible .
 Morphologic point of view, there are three types of glenoid
fossae:

 Type 1 – The anterior slope of the fossa is very light and,
although the condyle may not be seated as far back as it
can go in final closure, there will not be a great lateral
component of force on the teeth or a pressure on the
border of the meniscus. However, the ideal position of the
condyle in final closure is that in which it is completely
seated in the gleonoid fossa. This type of joint has the
greatest degree of tolerance.
 Type 2 – this is most commonly encountered. This joint has
little tolerance
 Type 3 - found occasionally . It has a very steep anterior
wall and has no tolerance . This type of joint causes the
most trouble since any slight eccentricity of the
maxillomandibular relationship causes a pressure on the
borders of the meniscus. If the condyle is not seated in the
fossa in final closure, it can result in a strong lateral strain
on the teeth

Anatomy of TMJ as it pertains to CR. Boucher JPD;
1962;12;464
 The external pterygoid muscle supports the mandibular
condyle on the articular eminence.
 Muscles limit the functional posterior border movements of
the mandible.
 He stated that centric relation is controlled by neuromuscular
reflex which does not necessarily always function in the
same anteroposterior position
 The terminal hinge position and the apex of the needle point
tracings of the retruded mandible may be desirable positions
from which to start the construction of dentures because they
are reference positions, but this does not imply that it may be
the ideal functional position of the mandible for all patients.

What is centric relation. George .Hughes
jpd;1964;14;1066
 The correct centric relation is essential in complete denture
construction.
 Prosthodontists disagree as to what constitutes centric
relation and how it is best registered.
 The present accepted definition of centric relation is based
upon the relationships of the mandibular condyles to the
glenoid fossae under normal or ideal conditions.
 The Gothic arch tracing is the best visual device for
ascertaining the horizontal relationships of mandibular
positions and two dimensional movements.

A critique of research of the posterior limit of the
mandibular position. Douglas Allen Atwood , JPD
;1968;20 ;21
 Two concepts of centric relation has been discussed , i.e ,
anatomic and pathophysiologic theory .
 Anatomic concept – centric jaw relation is the most posterior
position ( a border position established by ligament )
 Pathophysiologic concept – centric relation is the most
posterior unstrained jaw relation ( a relation which usually is
not a border position and is established by muscle action )
 He states the posterior limit of the mandibular position at the
vertical dimension of occlusion is usually established by
structures anterior and lateral to the condyles rather than
posterior to them. Both the temporomandibular ligaments
and the lateral pterygoid muscles are anatomically structured
to perform this function.

Diurnal variance of centric relation position. Shafagh
;1975;JPD;34;574
 He studied diurnal variance of recording maxillomandibular
relationships .
 He found that records obtained in the morning showed the
most antero inferior position of condyle and those made at
night showed the most posterior superior position
 If most retruded and superior position of condyles is desired ,
the evening seems to be a better time for making centric
relation record .

Discussion Of “The Anatomy Of The Temporomandibular
Joint As It Pertains To Centric Relation. Jamieson
;1962;JPD;12;473
 The article supports the theory that the retrusive movement
of the mandible in the glenoid fossae is limited by the
external pterygoid muscles and not by the mandibular
ligaments. It is generally agreed that the sphenomandibular
and stylomandibular ligaments do not limit the retrusive
movement of the mandible but rather assists in the limitation
of the lateral and protrusive movements.

FEATURES OF CENTRIC JAW RELATION
 It is learnable, repeatable, and recordable position which
remains constant throughout life.
 It is a reference position from which the mandible can move
to any eccentric position and return back involuntarily.
 It is the start point for developing occlusion.
 Functional movements like chewing and swallowing are
performed in this position, because it is the most unstrained
position.
 It is a reliable jaw relation, because it is bone to bone
relation.
 In case of dentulous patients proprioceptive impulses are
obtained from PDL.
 In case of edentulous patients centric relation act as
proprioceptive centre to guide occlusal movements.

 It is the only jaw position that permits an interference free
occlusion
 Centric relation is the ideal arch to arch relationship and an
optimum functional position of jaws for the health, comfort
and function of TMJ and musculature.
 Recording of an accurate centric relation is critical for the
most cost effective, time effective and trouble free prosthetic
dentistry.

CRITERIA FOR CENTRIC RELATION
The 2 most important criteria for Centric Relation are:
 The complete release of the inferior lateral pterygoid muscle
 Proper alignment of the disc on the condyle. During jaw
closure, with intact TMJ, the condyle-disc assemblies are
pulled up by a triad of strong elevator muscles.

TMJ SOCKET DESIGN
 The bony socket referred to as the glenoid fossa is the
structure that is effective in stopping the upward movement
of the condyle-disc assembly.
 The fossa is triangular shaped with the apex towards the
midline to accept the pure rotational axis of the medial poles
of the condyles.
 The wide part of the fossa accommodates the movement of
the lateral pole during rotation.
 The term centric means centered. The medial poles of the
condyles are centered in the middle of the medial third of the
fossa.

 When the condyles are fully seated, the front of the condyles
(with the disc interposed) contacts against the posterior
slope of the eminence.
 The upward movement is stopped by the contact of the
medial pole of the condyle with the heavily buttressed bone
up in the medial third of the fossa.
 At this point, the condyle disc assembly cannot move higher,
but it can rotate in that position, even under strong muscle
loading.

ROLE OF MUSCULATURE
 The elevator muscles are all present distal to the teeth,
between the teeth and condyles.
 Action of these elevator muscles pulls the condylar disk
assemblies against the eminence and slides them upwardly.
 The inferior belly of the lateral pterygoid is passive during jaw
closure unless activated by occlusal interferences to hold the
jaw forward.
 Mahan et al. say that the inferior belly of the lateral pterygoid
is almost always completely inactive during clenching in the
retrusive position.

CENTRIC RELATION IN A LOADING POSITION
Depending on the loading of temporomandibular joint:
 Passive centric : seen during passive closure of jaw in
centric relation or as projected in the articulator.
 Power centric : a dynamic centric observed during
mastication and deglutition.
 It has been reported that compressive forces acting on the
joint are relatively high and the surface of joint can withstand
this load .
 It is estimated that joint forces are more than 2.7 times that
of forces on the occlusal table.

 During mastication and deglutition , loading progresses and
the condyles are seated against the avascular aneural
central zone of the disc by contraction of the superior head of
external pterygoid muscle, the middle and anterior fibers of
temporalis muscle
 Hobo describes a buffer space of safety present between
condyle and fossa which prevent the transmission of heavy
load transferred to the condyle during function . It helps to
minimise the direct force on the disc and protect it from
anterior displacement and perforation .

COMPLICATIONS IN RECORDING CENTRIC
RELATION
 The structure of TMJs are such that one joint can be
displaced downward by uneven pressure when records
are made and yet the condyles be in their most retruded
position. This situation cannot occur on the articulator
and thus a deflective occlusal contact may be the source
of instability,soreness and resorption despite the
correctness of the other relations.
 Realeff effect by Hanau: according to it, there is uneven
resiliency in the soft tissues.This resiliency is present in
both the mucosa and the TMJs,thus undue pressure in
securing the relation must be avoided lest excessive
displacement of soft tissues occur
 Even though a balanced and equilized registration has
been made it often is lost due to:
Cast mounting procedures
Processing of denture

ERRORS IN CENTRIC RELATION
 When centric relation is not coinciding with centric relation of
the patient due to:
 Incorrect horizontal relation of the mandible to the maxilla
 Incorrect equalization of vertical contact.
Errors may be positional errors, technical errors.

POSITIONAL ERRORS:
 Failure of the operator in his registration of the correct
horizontal relationship.
 Failure of the operator to record equalized vertical contact
 Application of excessive closure pressure by the patient at
the time of recording
 Changes in the supporting area

TECHNICAL ERRORS:
 ill fitting occlusion rims: if record bases are not stable
 Indiscriminate opening and closing of the occluding device or
articulator; an articulator in reality is a jig which maintains a
record of position. Even if the casts are mounted correctly,
the amount which we can arbitrarily vary the vertical
distance between the casts is limited.
 Too frequently the lab technician opens and closes the
vertical distance of the articulator for the convenience in
tooth arrangement. this results in the establishment of the
centric occlusion which is not coinciding with centric relation.
 The slight shifting teeth which occurs between the stage of
final arrangement in wax and the transfer to a permanent
base material.
 A movement by the tooth or several teeth either horizontally,
or vertically, introduces an error.

Symptoms Which Result From Errors In Recording
Centric Relation
 Loss of retention
 Irritation on the crest of lower ridge in the area of
premature contact.
 One tooth or several teeth on one side seem long to
the patient or seem to strike first.
 Premature contact may be anteriorly or posteriorly.

ANTERIOR ERROR - when the centric occlusion established in
the arrangement of teeth is anterior to the centric relation.
POSTERIOR ERRORS - when centric occlusion established
is posterior to the centric relation of the patient.

FACTORS INFLUENCING CENTRIC RELATION
RECORDS
 The resiliency of the supporting tissues
 Fit of the denture bases
 Residual alveolar arch
 Saliva
 Tongue
 The health and cooperation of the patient
 The posture of the patient
 The temporomandibular joint and its associated
neuromuscular mechanisms
 The skill of the dentist
 The technique used and the recording devices used

CENTRIC RELATION AND CENTRIC
OCCLUSION
 Centric occlusion (GPT 8)- the occlusion of opposing teeth
when the mandible is in centric relation .
 The understanding of centric relation is complicated by
failure to distinguish between centric relation and centric
occlusion .
 Centric occlusion is a tooth-to-tooth position whereas centric
relation is bone to bone relation
 Both may or may not be identical to each other
 In persons with natural teeth, both centric relation and centric
occlusion exist. After the removal of teeth, centric occlusion
is lost ,while centric relation remains and serves as a reliable
guide to develop centric occlusion in artificial dentures .

RECORDING OF CENTRIC RELATION
 Assisting the patient to retrude the mandible
 Recording the centric relation
 Verifying the record

METHODS TO RETRUDE THE MANDIBLE
WHILE RECORDING CR
RELAXATION OF JAW:
 Simplest, easiest and most efficient way of causing a
retrusion of mandible in centric relation is by verbal
instructions to patients .
 Instruct the patient by saying “Let your lower jaw relax, pull it
back, and close on your back teeth”.
PUSHING UPPER JAW:
 In this method the 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 . Once this is
achieved, it is easy for them to repeat the desired motion .

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
 This protruding and retruding of mandible is done repeatedly
until the finger on the point of the chin can feel the mandible
strike its retruded position with a jar.
 The operator soon develops such a sense of touch that he
can feel this slight jar when the condyles hit the correct
position in the joint.

RETRUSION OF TONGUE
 Patient is instruction to keep the tip of tongue in contact with
the posterior border of the maxillary record base and then
patient is asked to close until the rims come into contact
 Useful in securing a tentative relation but not definite enough
for a final relation.
 Disadvantage : likehood of displacing the mandibular record
base by the action of tongue

RAPID TAPPING OF THE OCCLUSAL RIMS:
 Gentle tapping of occlusal rims rapidly and repeatedly
retrudes the mandible
 Disadvantage: Difficult to record and patient can easily tap in
a slightly protrusive or lateral position

HEAD POSITION:
 Tilting the head backwards results in retrusion of the
mandible because this will place tension on the
inframandibular muscles and tend to pull the mandible to a
retruded position
 Disadvantage: Insertion and removal of occlusal rims from
mouth a very difficult
SWALLOWING:
 Swallowing usually brings the mandible to a retruded position
.
 Unreliable – since person can swallow when mandible is not
completely retruded but 1-2mm anterior to maxilla .

TEMPORALIS MUSCLE CHECK :
 The temporalis muscle show reduced function when the
mandible is in a 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.
 However it can be used only as a slight indication of
proximity to a CR.
GENERALIZED RELAXATION OF THE PATIENT :
 Total relaxation of the patient on the chair automatically
brings mandible to retruded position
 It is however difficult to attain

DIFFICULTIES IN RETRUDING
 Biological problem
 Psychologial problem
 Mechanical problem

Biological Problem:
 Lack of muscle co-ordination
 Lack of synchronization between the protruding and
retruding muscles due to “HABITUAL” eccentric jaw positions
adopted by the patient to accommodate malocclusion
 This may due :
 Denture wearers with marked attrition of posterior teeth, as
sliding movements occur due to flat occlusal surfaces. This
leads to involuntary forward movement of the mandible.

 Also when a patient remains edentulous for a long time, the
meniscus and other tissues surrounding the condyle within
the capsular ligament gradually fill in the space created by a
continually protruded mandible.
 This condition prevents the immediate placement of the
mandible into its most retruded position.
 The following may help:-
 Muscle exercises prior to recording centric relation are
another physiologically sound device for causing a temporary
forgetting of the eccentric pattern.
 Drugs, e.g., Mephenesin
 patient relaxation
 jiggling the chin

Psychological Problem:
 It involves patient and dentist
 The more the dentist tries to overcome the apparent inability
of the patient to retrude the mandible, the more confused the
patient may become and the less likely he is to respond to
the directions provided by dentist .
 The dentist must be prepared to spend adequate time
securing the CR record

Mechanical Problems:
 Poorly fitting baseplates- it is essential that the record base
on which the centric relation are made fit perfectly and not
interfere with each other .
 Minimal pressure should be exerted during the registration ,
to avoid displacement of the soft tissue as much as possible
.

RECORDING THE CENTRIC RELATION
There two basic concepts:
 Minimum pressure technique
 Heavy pressure technique
MINIMUM PRESSURE TECHNIQUE:
 The record should be made with minimal closing
pressures so the tissue supporting the bases will not
be displaced while the record is being made.
 The objective of this concept is for the opposing teeth
to touch uniformly and simultaneously at their first
contact

HEAVY CLOSING PRESSURE:
 This states that the records should be made under
heavy closing pressure so that tissues under the
recording bases will be displaced while the record is
being made .
 The objective of this concept is to produce the same
displacement of the soft tissue as would exist when
heavy closing pressure were applied on the denture .

METHODS OF RECORDING CENTRIC
JAW RELATION
1. Physiological method:
-Tactile or interocclusal check record method
-Pressure less method
-Pressure method
2. Functional method:
-Needles house method
-Patterson method
3. Graphic method:
-Intra oral method
-Extra oral method
4. Radiographic method

PHYSIOLOGIC METHOD
 Based on:
-Proprioceptive impulse of patient
-Kinethetic sense of mandibular movement
-Visual acuity and sense of touch of patient
 Types:
a. Tactile or interocclusal check record method
b. Pressure less method
c. Pressure method

Tactile Or Interocclusal Check Record Method:
 Tentative jaw relation is recorded.
 Ask the patient to retrude the mandible.
 Casts are articulated based on this tentative record
a) Recording tentative jaw relation:
 Maxillary occlusal rim inserted to patients mouth.
 Vertical dimension at rest is established. mandibular
occlusal rim inserted and reduced accordingly.
 Tentative centric relation recorded using tentative jaw
relations. Artificial teeth are arranged.

b) Making the inter occlusal check record:
 Upper and lower trial dentures are inserted into the
mouth. keep a piece of cotton to prevent contact of
opposing members.
 Aluwax is added on the occlusal surface of teeth of
mandibular occlusal rim
 Patient asked to retrude mandible and close on the
wax till tooth contact occurs.
 Trial dentures removed and allowed to cool.

Static Or Pressure less Method:
Nick Notch Method:
 Patient asked to retrude mandible in position.
 Upto 3mm of wax removed from mandibular occlusal
rimfrom the premolar region till the distal end
 1 or 2 notches are cut on the corresponding area of
maxillary occlusal rim.
 One nick is cut anterior to the notch, a V shaped valley
 Nick: prevent lateral movement
 Notch: anteroposterior movement

 Nick and notch are lubricated with petroleum.
 Prepared occlusal rim are inserted into patient’s mouth
and taught to close his mandible in maximum retruded
position.
 Aluwax is placed on the trough created in mandibular
rim.
 Mandibular occlusal rim is cooled and inserted into
patients mouth and closed in centric relation.

Pressure Method:
 Establish vertical dimension.
 Upper occlusal rim inserted. Lower occlusal rim is
fabricated by softening in water bath.
 Insert it into patients mouth.
 Patient asked to close mouth in centric relation on soft
wax in predetermined vertical dimension and then
articulated.

FUNCTIONAL METHOD
 These methods utilize the functional movements of the
jaws to record the centric relation.
The patient is asked to do the movements in
protrusion, retrusion and right lateral and left lateral.
 Types:
-Needles House Method
-Patterson method

Needles House Method:
 Fabrication of occlusal rim made from impression
compound
 Four metal beads or styli are embedded into
premolar and molar areas of maxillary occlusal rim.
 Occlusal rim inserted into patients mouth and asked
to close occlusal rim and make protrusive, retrussive,
right and left movement of mandible.
 When movements are made “diamond shaped
marking pattern rather than a line is formed on the
mandibular occlusal rim.

Patterson Method:
 Occlusal rim made of modelling wax.
 In trench or trough is made along the length of
mandibular occlusal rim.
 A1:1 mixture of pumice and dental plaster is loaded
into the trench.
 Perform mandibular movement till predetermined
vertical dimension.
 Movement generates compensative curves in plaster.

GRAPHIC METHOD
 These methods are called so because they use graphs or
tracing to record the centric relation.
 The general concept of this technique is that a pen-like
pointer is attached to one occlusal rim and a recording plate
is placed on the other rim, the plate coated with carbon or
wax on which the needle point can make the tracing, when
the mandible moves in horizontal plane, the pointer draws
characteristic patterns on the recording plate.
 The graphic methods are either intraoral or extraoral
depending upon the placement of the recording device. The
extraoral is preferable to the intraoral tracing, because the
extraoral is more accurate, more visible, and larger in
comparing with the intraoral tracing.

 Types:
 Arrow point/Gothic arch tracing
(Intraoral/extraoral – depending on placement of device)
 Pantograph
 Arrow point tracing is a graphic record measured across
single plane
 Pantogaph is measured three dimensionally.

Arrow Point/Gothic Arch Tracing:
TYPES:
1) INTRA ORAL TRACING POINT:
 Central bearing device is located intra orally.
 Tracer is placed within the mouth.
 Central bearing point & plate is inserted into patients
mouth.
 Central bearing point is adjusted such that it contact the
central bearing plate at predetermined vertical dimension.
 Ask to make anteroposterior and lateral movements.
 Central bearing point will draw the tracing pattern on
central bearing plate
 Tracing should resemble an arrow point with a sharp apex.

2) EXTRA ORAL POINT TRACER:
 Concept similar to intra oral tracer.
 Additionally have an attachment that project outside mouth.
 Record bases attached to recording devices inserted in
patients mouth.
 Central bearing point is retracted to conduct training
exercises.
 Recording plate which projects extra orally is coated with
precipitated chalk and denatured alcohol.
 Patient asked to perform all movements.
 Examine for sharp apex.

EXTRA AND INTRA ORAL TRACING
EXTRAORAL TRACING:
 Larger than intraoral
 Apex is more discernible
 It is visible while tracing is being done, so easier to guide the
patient
 Patient can be guided properly
 Tracing point is sharper than the intra oral one.
 Tracing plate is mounted on the mandibular rim
 Error can be more as
- tracing is situated outside the mouth further away from the
centers of mandibular movement.
-presence of extra oral tracer prevent the lips from meeting
each other and remain passive

TYPES OF EXTRA ORAL TRACERS
 Hight tracers(with or without central bearing point)
 Stransbery tracers

 Sears trivet (is a central bearing point tracer with two
registration pins)

 Phillips tracer (multiple tracers)
 Multiple tracers add little to the accuracy of the tracing but do
add something to the understanding of the mandibular
movement.

TYPES OF INTRAORAL ARROW
TRACERS
 Ballard
 Masserman

 Coble tracer
 Micro tracer

Pantographic Tracing:
 A graphic record of mandibular movements in three planes
as registered by styli on recordable tables of a pantograph
tracing of mandibular movement recorded on plates in
horizontal and sagittal planes.
 Make the rim contact at desired vertical relationship.
 Strips of celluloid paper are placed between the rim and
pulled out. Patient is asked to close and restrain the celluloid
from slipping away, mandible goes to centric relation.
 Softened wax is placed on mandibular occlusal rim and
patient is asked to bite in centric relation.

 An eccentric relation is any relationship of the mandible to
the maxillae other than centric relation.
 The purpose in making an eccentric relation record is to
adjust the horizontal and lateral condylar inclinations so that
the articulator jaw members perform eccentric movements
equivalent.
 This permits to arrange the teeth in balanced occlusion
 Eccentric positions: protrusive, retrusive, right lateral and left
lateral.
Methods to Record:
 Functional or chew in
 Graphic
 Tactile or direct check record.

 LATERAL RELATION RECORD:
Hanau recorded a formula to arrive at an acceptable lateral
inclination
L=H/8+12
Where L= lateral condylar guidance,
H= horizontal condylar guidance
 Eccentric maxillomandibular relation records is performed at
the same setting, same sitting and with the same equipment
used for centric relation

SUMMARY
 Centric relation is a most reproducible , reliable, repeatable
, recordable, and reference position
 CENTRIC RELATION IS DEFINED AS THE
maxillomandibular relation in which the condyles articulate
with the thinnest avascular portion of their respective
articular disks with the complex in an anterio superior
position against the slopes of articular eminences.
 Eccentric relations are any other positions other than centric
relation-p
 Centric relation should coincide with centric occlusion
otherwise will affect the stability of the dentures.
 It can be recorded by various methods:
Direct recording
Graphic recording
Functional recording
Cephalometric recording

CONCLUSION
 Any dentist who is willing to spend the time and energy to
master the technique of recording and verifying precisely
correct horizontal jaw relation will benefit in untold ways.
There is no procedure in dentistry that can produce as many
tangible benefits to both the doctor and the patient as the
routine correct recoding of horizontal jaw relation, verified for
accuracy as it affects the health , comfort, function of the
muscles, and Temporomandibular joint.

REFERENCES
 Zarb GA,Bolender CL,Carlsson GE Boucher’s prosthodontic
treatment for edentulous patients 11th edition
 Dawson PE Evaluation,diagnosis and treatment of occlusal
problems 2nd edition
 Sharry JJ Complete denture prosthodontics 3rd edition
 Heartwell CM,Rahn AO Syllabus of complete dentures 4th
edition
 Winkler’s Essentials of complete denture prosthodontics 2nd
edition

Horizontal Jaw Relation

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