This document discusses centric relation, which refers to the relationship between the mandible and skull when the condyles are in their most superior position in the mandibular fossa against the posterior slope of the articular eminence. It has gone through various changing definitions but is now widely accepted to mean the anterior-superior position. Recording centric relation is important for complete denture construction as it provides proprioceptive feedback and acts as the starting point for occlusion. There are various passive and active methods to retrude the mandible as well as intraoral and extraoral graphic methods to record the position.

1. CENTRIC RELATION-
RELEVANCE AND ROLE
IN COMPLETE DENTURE
CONSTRUCTION
Namitha AP
2ND MDS

2. Contents
 INTRODUCTION
 DEFINTION
 CHANGING
DEFINITIONS OF
CENTRIC RELATION
 CONFUSION OVER
CHANGING
DEFINITIONS OF
CENTRIC RELATION
 FEATURES AND
SIGNIFICANCE OF
CENTRIC RELATION
 FACTORS
INFLUENCING
CENTRIC RELATION
 METHODS OF RETRUDING
THE MANDIBLE
 DIFFICULTIES IN
RETRUDING THE
MANDIBLE
 METHODS OF RECORDING
CENTRIC RELATION
 REVIEW OF LITERATURE
 CONCLUSION
 REFERENCES

3. INTRODUCTION
MAXILLO
MANDIBULAR
RELATIONS
JAW
RELATIONS
ORIENTATION VERTICAL HORIZONTAL
CENTRIC
RELATION
ECCENTRIC
RELATION

4. DEFINITION
 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).

6. Centric relation
Refers to the RELATIONSHIP of the MANDIBLE TO THE
SKULL as it rotates around the ‘hinge-axis” before any
translatory movement of the condyles from their “upper-most
and mid-most position”.
It is irrespective of tooth position or vertical dimension.
Peter E. Dawson. Evaluation, Diagnosis, and Treatment
of Occlusal Problems, 2nd ed.. Mosby.

7. CHANGING DEFINTIONS OF
CENTRIC RELATION
 "The most posterior relation of the lower to the
upper jaw from which lateral movements can be
made at a given vertical dimension” (Boucher)
 "A maxilla to mandible relationship in which the
condyles and discs are thought to be in the
midmost, uppermost position. The position has
been difficult to define anatomically but is
determined clinically by assessing when the jaw
can hinge on a fixed terminal axis (up to 25 mm).It
is a clinically determined relationship of the
mandible to the maxilla when the condyle disc
assemblies are positioned in their most superior
position in the mandibular fossa and against the
distal slope of the articular eminence” (Ash)

8. • He showed that the condyle had a pure
rotational movement when the operator
guided the mandible to position the condyles
in the most retruded position in the glenoid
fossa.
• He was the first to name this position as
centric relation
MCCOLLUM
(1920) – REAR
MOST CONDYLAR
POSITION
• A second component for bracing a most
superior position was considered necessary
since the condyle was unstable when it was
only in the most posterior position.
GRANGER (1962)
– UP MOST REAR
MOST POSITION.
• Condylar position in the glenoid fossa.
• A medial component was added for the
stable condylar position (3 dimensional
positions).
• It was considered a physiological condylar
position harmonious with centric occlusion.
STUART (1969) –
REARMOST
UPPERMOST
MIDMOST (RUM)
CONFUSION OVER CHANGING
DEFINITIONS OF CENTRIC
RELATION

9. CELENZA (1978)
Condyle disk assembly brazed superiorly and anteriorly against
the posterior slope of eminences. Today this is widely
accepted for condylar position.
Posterior positioning of the condyles is no longer considered
desirable (Celenza)

10. ANTERIOR-SUPERIOR POSITION
Thickening (buttressing) occurs
in areas of bone where
articulation occurs
- Thickest part of the articular
eminence is the anterior portion
of the glenoid fossae

11. ANTERIOR-SUPERIOR POSITION
 The neurovascular
supply of the retro-
discal pad is posterior to
the articular disk
 If condyles articulated in
a most posterior
position – impingement

12. ANTERIOR-SUPERIOR POSITION
• Fibrocartilage on anterior, not
posterior to the glenoid fossae
 Articular cartilage is present
superior and anterior to the
condyles
CARTILAGE COVERS ARTICULAR
SURFACES

13. ANTERIOR-SUPERIOR POSITION
 Posterior-most
positions require
force
 Pressure may force
condyles down
posterior slope, or
cause flexure of
mandible

14. • Centric relation is not a resting or postural position of the
mandible.
• Contraction of muscles is necessary to move & fix the mandible in
centric relation position.
• The masseter, temporal, 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 the centric relation position.
MUSCLE INVOLVEMENT IN
CENTRIC RELATION

15. CENTRIC OCCLUSION (CO)
 Obsolete term
 Maxillo-mandibular position determined by teeth
 Sometimes considered coincident with ‘maximum
intercuspation’ or ‘habitual closure’

16.  Mann and Pankey defined long centric or freedom in
centric by means of occlusal balance with anterior sliding
movement between the terminal hinge axis position and
habitual intercuspation of 1 mm.
T. Badel et al. Acta Stomatol Croat, Vol.
35, br. 382 3, 2001

17. CENTRIC RELATION OCCLUSION
 When CO & CRO are coincidental. This is the ideal
occlusion that we aim for in an equilibrated mouth ie.
simultaneous contact of all the teeth with the condyles in
centric relation
 The position of the mandible which is determined by
tooth to tooth contact when the mandible closes in CR.
 Retruded Contact position

18. FACTORS INFLUENCING CENTRIC
RELATION
1. Resiliency of the supporting
tissues
2. Stability of the recording
bases
3. TMJ and its neuromuscular
mechanism
4. Pressure applied in making
the record
5. Technique
6. Skill of the operator
7.The health and
cooperation of the
patient
8.The maxillomandibular
relationship
9.The posture of the
patient
10.The character or size of
the residual alveolar
arch.
11.The size and position
A. Albert Yurkstas et al. J Prosthet Dent.
2005:93:305:
A. Albert Yurkstas et al. J Prosthet Dent.

19. Significance
 proprioceptive impulses
are obtained from the
periodontal ligament
 do not have any
proprioceptive guidance from
their teeth to guide their
mandibular movements.
 The source of the
proprioceptive impulses
transferred to the
temporomandibular joint.
 The centric relation position
acts as a proprioceptive
center to guide the
mandibular movements
Dentulous patients Edentulous patients
proprioceptive impulses (impulses of three dimensional spatial orientation) guide
the mandibular movements

20. Salient features
 It is learnable, repeatable and recordable position
which remains constant throughout life.
 It is a definite learned position from which the
mandible can move to any eccentric position and
return back involuntarily
 It acts as a center from which all movements can
be made.
 If the mandible has to move from one eccentric
position to another it should go to the centric
relation before advancing to the target eccentric
position

21.  Ideal arch to arch relationship and starting point to
plan & execute the occlusion
 Related to terminal hinge axis. In centric relation,
condyles exhibit pure rotation without any translation
 Reference position for the institution of occlusal
rehabilitation in dentulous conditions.
 In natural dentition if centric relation & centric
occlusion doesn’t coincide periodontal structures are
endangered.

22.  More definite than the vertical relation and is
independent of the presence or absence of teeth.
 Functional movements like chewing and
swallowing are performed in this position,
because it is the most unstrained position.
 The muscles that act on the temporomandibular
joint are arranged in such a way that it is easy to
move the mandible to the centric position from
where all movements can be made.
 The casts should be mounted in centric relation
because it is the point from which all the
movements can be made or simulated in the
articulator.
 It is helpful in adjusting condylar guidance in an
articulator to produce balanced occlusion

23. Retruding the mandible
 The mandible
should be in its most
posterior position
while recording
centric relation.
Retruding
mandible
Passive
methods
Active
methods

24. PASSIVE METHODS
1.Relax, pull the jaw back and close on the back teeth.
2.Touch the posterior border of the upper record base with
his tongue and close till the rims contact.
3.Swallow and close
4. Mandibular occlusal rim should be tapped gently with a
finger. This would automatically make the patient to
retrude his mandible.

26. PASSIVE METHODS(CONTI.)
6.Get the feeling of
pushing the upper jaw
out and close on back
teeth
7.Tilt the head back while
performing the above
exercises
8.Protrude and retrude the
mandible repeatedly
holding his fingers lightly
against the chin.
9.Tapping the back of head

27. ACTIVE METHODS
 The dentist places his thumb and forefinger on the patient’s
chin to exert a mild but firm posterior force while patient closes
on the rims. This will prevent the patient from moving the jaw
anteriorly.
 Dentist palpates the temporal and masseter muscles to relax
them.

29. BIMANUAL PALPATION – Introduced by
Dawson

30. DETERMINING CENTRIC RELATION IN
DENTULOUS PATIENTS
 ANTERIOR BITE STOPS
 ANTERIOR DEPROGRAMMING DEVICE
 THE PANKEY JIG
 BEST-BITE APPLIANCE
 LUCIA JIG
 NOCICEPTIVE TRIGEMINAL INHIBITION (NTI)
 LEAF GAUGE

32. Difficulties in retruding the
mandible
• Inability of the patient to follow the dentist's
instruction
• stretch relax exercises, training the patient to
open and close his mouth, etc.
• Central bearing devices can be used
physiological
• Lack of co-ordination between groups of
opposing muscles
• Habitual eccentric jaw relation.biological
• Poorly fitting base plates
• The base plates should be checked using a
mouth mirror for proper adaptation.mechanical

33. Methods of Recording the Centric
Jaw Relation
• Tactile or inter-
occlusalcheck record
method
• Pressureless
method.
• Pressure method
PHYSIOLOGICAL
METHODS
RADIOGRAPHIC
METHOD
• Needleshouse method
• Patterson method
FUNCTIONAL
METHOD
• INTRAORAL
• EXTRA ORAL
GRAPHIC
METHOD
Centric
relation
static functional
Boucher 9th edition

35. I .PHYSIOLOGICAL METHODS
 Physiological methods are called so because
they are based on:
• 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

36.  Abnormally related
jaws.
 Displaceable,flabby
tissues.
 Large tongue.
 Uncontrollable
mandibular
movements.
 Patients already using
a complete denture.
 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.
INDICATIONS
Factors affecting the success of
inter occlusal record method

37. A.TACTILE/INTER OCCLUSAL
CHECK RECORD METHOD
Tentative
centric jaw
relation
Interocclusal
check record

38.  Limited resistance before setting to avoid displacing the teeth or
mandible during closure
 Rigid or resilient after setting
 Minimal dimensional change after setting
 Accurate record
 Easy to manipulate
 No adverse effects on the tissues involved in the recording
procedures
 Should be verifiable
CHARACTERISTICS OF IDEAL INTER-
OCCLUSAL BITE REGISTRATION MEDIUM

39. Commonly used materials
• technique-sensitive and do not provide uniform resistance to pressure
because they do not cool uniformly. The advantage of waxes is that
they harden very quickly and the record can be made immediately.
Hence, they are used only in patients with poor muscular control.
Waxes
impression compound
ZnOE
impression plaster
Addition silicone
Poly ether
usually preferred because they offer uniform
resistance to pressure.The disadvantage of these
materials is that they take a long time to set and
any movement made while the material hardens,
can render the inter-occlusal record useless.
Fattore, L. et al. Clinical evaluation of the accuracy of interocclusal
recording materials. J Prosthet Dent.1984;51: 152-57.

40. Myers, M. L. Centric relation records – historical review. J
Prosthet Dent 47. 1982:141-145.
• Wax checkbite was the technique of choice
for recording CR under light pressure.Trapozzano
• Modeling compound was preferable
because it softened more evenly, cools
slower and does not distort as much as
wax. Light pressure. Verification of records.
Schuyler
• Plaster is more accurate, less material
needed, less pressure
Payne,
Hickey, and
Boos

41. • Realeff = resilient and like effect. Concern for equalization
of pressure when recording the bite.hanau
• Of the four factors, resiliency of tissue, salivary film, fit of
bases and pressure, the dentist cannot control pressure.
He therefore advocated zero pressure.
wright
• Plaster is the only accurate material.
Gysi
• Centric records were worthless the instant the surfaces
are altered.
Page
Myers, M. L. Centric relation records – historical review. J
Prosthet Dent 47:141-145, 1982

42. Tentative jaw relation
the trial dentures are ready for making the interocclusal check record.
A tentative centric relation is recorded by using one of the previously mentioned methods to retrude the mandible
The occlusal rims are articulated using the tentative jaw
relations
Artificial teeth are arranged
The vertical dimension at rest is established
mandibular rim is reduced further for excess interocclusal distance
The maxillary occlusal rim is inserted into the patient's mouth.
A denture adhesive can be used to improve retention.

43. Making the interocclusalcheck
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 wax till tooth contact
occurs.
The upper and lower trial dentures are inserted into the patient's mouth
The artificial teeth are prevented from contacting the opposing members by keeping a
piece of cotton inter-occlusally.

45. If anyone of the condylar elements (condylar element represents the condyle in the
articulator) do not contact on the centric stops (centric stop represents the centric position of
the condyle in the glenoidfossa) it indicates that the tentative recording is inaccurate.
Occlusal indicator wax can be used instead of Aluwax for recording trial dentures with
non-anatomical (cuspless) teeth.
The Aluwax on the buccal aspect of mandibular teeth is scraped off and the articulated casts
(which are free to move horizontally) are adjusted to fit into the Aluwax check record.
If the tentative relation record is accurate and is the same as the check record then
both the condylar elements of the articulator will contact against the centric stops,i.e.
the articulated casts need not move to fit into the check records.
Both the maxillary and mandibular trial dentures are placed on their articulated casts.
Before placing the trial dentures, the horizontal condylar guide locks in the articulator
are unlocked to allow free horizontal movement of the casts.

46. B.STATIC OR PRESSURELESS
METHOD
The occlusal rims are customized
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
The nick and notch method or the stapler pin
method can be used to index/seal the occlusal
rims.

47. Nick and Notch method
 Most commonly used method of indexing the
recorded centric jaw relation
 final centric jaw relation is carried out after
establishing a proper vertical jaw relation
 No occlusal check records are performed
during try-in.
 name from the shape of the indices made on
the occlusal rims.

48. PROCEDURE
The patient is seated in an upright
position,as it is easier to retrude the
mandible in this 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 {nick prevents lateral movement and the
notch prevents anteroposterior movement).

50. The nick and the notch on the
maxillary occlusal rim are lubricated
with petrolatum
Once the patient has learned to
close his mouth in centric
relation,he is asked to repeatedly
practice it,till the dentist is satisfied.
The mandibular occlusal rim is
removed from the patient's mouth.
Aluwax (Aluwax dental products
company, Grand Rapids, Michigan)
is placed on troughs created in the
mandibular rim.

51.  About 4.5mm of Aluwax should be placed on the
trough Pressure method so that about 1.5 mm of
Aluwax will be projecting above the upper the
mandibular occlusal rim.
 ZOE and impression plaster can also be used as
a substitute for Aluwax
 The mandibular occlusal rim is placed in a water
bath to soften the wax and inserted into the
patient's mouth.
 The patient is asked to close in centric relation
with professional guidance.
 The mouth should close such that the anterior
parts of the occlusal rims almost touch but not
press against

52.  Both the occlusal rims are removed, cooled and
articulated, each other. The Aluwax projecting
above the trough of the mandibular rim will flow
into the nick and notches.
 The occlusal rims are removed and placed in a
coldwater bath till the wax hardens.
 The excess Aluwax present buccally and
lingually.The patient is asked to should be
trimmed.
 Care should be taken to prevent damage to the
occlusal surface of the nick and notch
 Since petrolatum was applied,it will be easy to
separate the rims without damaging the index

54.  Both the occlusal rims should be placed against each
other and checked if the Aluwax extends between the
nick and the notch.
 The notches can be placed on the mandibular rim and
the Aluwax can be placed on the maxillary rim if
necessary.
 The maxillary occlusal rim is placed on the articulated
maxillary cast (articulated after orientation jaw
relation).
 articulator with the maxillary cast is placed upside
down.
 The mandibular rim along with the cast is positioned
against the maxillary rim such that it coincides with
index records (Nick and notch)

55. The nick and notch method or the stapler pin method
can be used to index/seal the occlusal rims.

56. Stapler pin method of indexing
static centric relation:
 In this method, after recording the centric
relation, the occlusal rims are indexed using a
bunch of stapler pins.
 The method is not preferred as centric relation
record can not be verified.

57. Tripodakis et al, carried out a study to determine the accuracy of the
fit of interocclusal records on the working casts.
The results indicated that the presence of the recording material
produced vertical discrepancies on the interocclusal relationships of
the casts.
Maj P.Dua. MJAFI. 2007;63:237
Studies related to inter occlusal
records

58. Evaluation of Four Elastomeric Interocclusal
Recording Materials
A study was conducted to evaluate the dimensional changes
occurring in various interocclusal recording materials over a
given period of time and the material’s resistance to
compression during the cast mounting on the articulator.
Addition silicone showed highest compressive resistance
and were the most dimensionally stable of all materials.
Maj P.Dua. MJAFI. 2007;63:237

59. Comparative Evaluation Of Dimensional Stability Of 3
Types Of Interocclusal Recording Materials
 Polyvinyl siloxane
 Zinc oxide eugenol paste
 Bite registration wax (Aluwax)
Polyvinyl siloxane was dimensionally the most stable.
The ideal articulation time based on polyvinyl siloxane
material was less than 24 hrs and for zinc oxide eugenol it
was 1 hr.
Kartikeyan J Indian Prosthodontic Society. 2007;7:1:24

60. •Dixon et al compared and measured the accuracy of thermoplastic
resins, acrylic resins and addition silicone interocclusal recording
materials.
They used a measuring method developed on a computer
axiograph to record positional errors in three planes.
The addition silicone group generated significantly less mounting
errors than those generated by the acrylic resins and thermoplastic
resins.
Maj P.Dua. MJAFI 2007;63:237

61. Accuracy and dimensional stability of four
interocclusal recording materials
• The eugenol free-zinc oxide paste exhibited dimensional
stability for the 168- hour period.
• Polyether was the second most accurate and stable material
(0.3% shrinkage after 24 hours).
• Zinc oxide-eugenol paste was the least accurate of the
materials tested.
• Silicone putty is not recommended due to initial inaccuracy
and because its rate of contraction precludes storage of the
registration.
Balthazar-Hart, Y. et al. Accuracy and dimensional stability of four
interocclusal recording materials. J Prosthet Dent. 1981; 45:586-91.

62. PRESSURE METHOD
 Here, after establishing the vertical dimension, the
upper occlusal rim is inserted into the patient's
mouth.
 The lower occlusal rim is fabricated to be of
excess height. The entire lower occlusal rim is
softened in a water bath and inserted carefully
into patient’s mouth
 The patient is guided to close his mouth in centric
relation. The dentist should gently guide the
mandible
 The patient is asked to close on the soft wax. After
the patient. closes his mouth till the predetermined
vertical dimension, both the occlusal rims are

63. II.FUNCTIONAL METHOD/CHEW
IN METHOD
 utilize 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 the mandible.

64. Factors common to all functional
methods
 tentative centric relation and vertical dimension are
measured for determining an accurate centric relation.
 The occlusal rims are reduced in excess than that
required for the tentative vertical dimension.
 The exact vertical dimension at occlusion is determined
only when the patient closes on the occlusal rims and
their attachments (tracers etc).

65. HISTORICAL REVIEW FOR FUNCTIONAL
METHOD
• Greene (1910) Wax occlusal rims and plaster index.
• Boos used the Gnathodynamometer to determine the
vertical and horizontal position at which a maximum biting
force could be produced. His Bimeter was mounted on the
lower occlusal rim with a central bearing point against a
plate on the upper occlusal rim. Plaster registrations were
made.
• Shanahan placed cones of soft wax on the mandibular rim
and had the patient swallow several times to record centric
Myers, M. L. Centric relation records – historical review. J Prosthet Dent. 1982;
47:141-5.

66. DISADVANTAGES
Inaccuracy can result from:
• Displaceable basal seat tissues
• Resistance of recording mediums
• Lack of equalized pressure
Patients must have very good neuromuscular
coordination and be capable of following instruction.

67. A.Needlehouse method
 This is one of the most commonly used
functional techniques . • It involves the
fabrication of occlusal rims made from
impression compound. • Four metal beads or
styli are embedded into the premolar and
molar areas of the maxillary occlusal rim.

68.  The occlusal rims are inserted
into the patient's mouth
 The patient is asked to close on
the occlusal rims and make
protrusive, retrusive, right and
left lateral movements of
themandible.
 When the patient moves his
mandible, the metal styli on the
maxillary occlusal rim will
create a marking on the
mandibular occlusal rim.
 When all the movements are
made, a diamond-shaped
marking pattern rather than a
line is formed on the
mandibular occlusal rim
 The posterior most point of this
diamond pattern indicates the

70. B.Patterson’s method
 Here occlusal rims made of modeling wax are
used.
 A trench or trough is made along the length of
the mandibular occlusal rim
 A 1:1 mixture of carborundum and dental
plaster is loaded into the trench
 The occlusalrims are inserted and the patient
is asked to perform mandibular movements.
 These movements will produce compensating
curves on the plaster carborundum mix

73.  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

74. III.GRAPHIC METHODS
Graphic
methods
Arrow point
tracing
measured
across a single
plane
Popularized by
Gysi,1908
Proposed by
Hesse 1897
pantograph
measured
three-
dimensionally.
•uses graphs or tracings to record
the centric jaw relation.

75. Why “Gothic Arch”?

76. Historical review for Graphic Recordings
• Balkwill (1866): Gothic arch tracing.
• Hesse (1897): “Needle point tracing".
• Gysi (1910): Extraoral incisal tracer on maxillary rim traced onto
the tracing plate attached to the mandibular rim.
• Phillips developed a plate for the upper rim and a tripoded ball
bearing mounted on a jackscrew for the lower rim. The occlusal
rims were removed and softened compound was inserted
between the trial bases. This innovation was called the "central
bearing point" which supposedly produced equalization of
pressure on the edentulous ridge.

77. Myers, M. L. Centric relation records – historical
review. J Prosthet Dent. 1982;47:141-5.
• Stansbery (1929) used a curved plate corresponding to
Monson’s curve mounted on the upper rim. A central bearing
screw was attached to a lower plate with a reverse-Monson
curve. Plaster was used to form the centric registration.
• Hall (1929) used the Stansbery’s technique but substituted
compound for the centric relation record.
• Hardy and Pleasure called their intra oral tracer: the Coble
Balancer.

78.  Robinson designed the Equilibrator with a hydraulic
system and four bearing pistons.
 Silverman used the intraoral Gothic arch tracer to locate
the biting point of a patient.
 Hanau conceded that Gysi tracing was satisfactory to
check records, but that universal usage was not good.
 Tench stated that the Gysi tracing technique was the only
means of recording CR.
Myers, M. L. Centric relation records – historical review. J Prosthet Dent. 1982; 47:141-5.

79. INDICATIONS
 Well healed broad edentulous ridges
 Adequate inter arch space
 In patients with habitual centric; the use of the
graphic method eliminates all occlusal contacts on
the occlusal rims, thus breaking the neuromuscular
reflex and allows the patient to record his true centric.

80. CONTRAINDICATIONS
• Severely resorbed ridges.
• Excessively flabby ridges.
• Difficult to place in the presence of large tongue.
• Decreased arch space  difficult to place central
bearing device without raising the VD.
• In patient with temporomandibular joint arthropathy.
• In patient with abnormal jaw relations

81.  Documented to be the most
accurate method of recording
CR.
 Allows equalization of
pressure on the supporting
tissues.
 Easily verifiable.
 Can also be used to record
eccentric relations.
 May be difficult to locate the
centre of the arches which is
very important for central
bearing function and
accuracy of tracing.
 More time consuming.
 Training patient in making
mandibular movements is
strenuous.
Advantages disadvantages

82. Factors to be considered while
carrying out tracing procedures
 Stability of the denture base.
 Resistance offered by the occlusal rims against occlusal
forces.
 Difficulty in placing the central-bearing device in protruded
and retruded jaws.
 Presence of flabby tissue and its effect on the denture base.
 Height of the residual alveolar ridge influencing the stability of
the record base.
 Interference from the tongue.
 Efficiency of the recording devices during physiological
mandibular movements.
 Obtaining a pointed apex in the tracing pattern. (All tracing
patterns will have an apex which is a single point from where
all patterns appear to arise from)
 Lack of coordinated movement. This can cause double
tracing.

83. tracers
Extra-
oral
Intra-
oral

85. Arrow point tracing
The characteristic pattern created on the recording plate is called a central
arrow-point tracing.It is defined as, 'The pattern obtained on the horizontal
plate used with a central bearing tracing device"—GPT.

86. Central bearing device
Central bearing
device
Central bearing
point/stylus
pen-like pointer
is attached to
one occlusal
rim
Central bearing
plate
placed on the
other rim
These parts are called central bearing because they act at the center of the arch
and evenly distribute forces across the supporting structures
When the mandible moves the
pointer draws characteristic
patterns
It is a one-dimensional graphic tracing
made using gothic arch tracers.It is usually
recorded in the horizontal plane.

87. The apex of the arrow point tracing gives the centric relation. The apex of the
arrow head should be sharp else the tracing is incorrect

88. Central bearing device
 Central bearing device or central bearing tracing
device is defined as,"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.
First attributed to AlfredGysi, Swiss
prosthodontist,in 1910"—GPT9
PUT FORWARD BY STANSBERRY

89. Central bearing point
 : It is defined as, "The contact point of the central
bearing device"—GPT.
 It is a 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.
 The pointer can be adjusted in height.It is usually
attached to the mandibular occlusal rim but can
also be attached to the maxillary rim
 Since it is placed across the tongue space of the
mandibular occlusal rim; it cannot be used in
patients who can not retract the tongue sufficiently
and those who have macroglossia.

90. 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.It is usually
attached to the maxillary occlusal rim. A
mixture of denatured spirit and precipitated
chalk is coated on this plate. The spirit dries to
leave a fine layer of precipitated chalk. The
tracing is marked on this layer of precipitated
chalk

91. Intraoral tracing assembly

92. Intra oral tracers

94. BALLARD INTRA ORAL TRACING DEVICE
Metal points attached to the upper modeling compound rim will
cut pathways in the occlusal surface of the lower modeling
compound rim as the patient moves the mandible from side to
side.
Palatal bearing plate
Rounded head of correlator pin
Tension spring
Adjustable screw
Mounting plate
Pointed end of correlator pin

95. COBLE INTRA ORAL TRACING DEVICE
The central bearing point is attached with modeling compound
to the upper Base plate in the center of the palate at the
intersection of the midline and a line joining the centers of left
and right chewing areas.

104. PROCEDURE FOR INTRA ORAL
TRACING
 The record bases attached to the central-
bearing point and the central-bearing plate
(coated with chalk) are inserted into the
patient's mouth.
 The central bearing point is adjusted such that
it contacts the central-bearing plate at a
predetermined vertical dimension

105. When the patient closes his mouth, the central bearing point contacts the
metal plate.

106.  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 central-bearing plate.
 After completing the movements, the tracing is
removed and examined. The tracing should
resemble an arrow point with a sharp apex. If
the apex is blunt, the record is discarded and
the procedure is freshly repeated.

107. PROCEDURE FOR EXTRAORAL
TRACING
 The maxillary cast is mounted on the articulator with a facebow
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, in a comfortable position on

108.  The record bases with the attached devices are inserted in the
patient’s mouth. They are checked for stability, contact during
mandibular movements and interference.
 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.
 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.

109. This is a tentative relation and should be checked using
pointer.

110. • 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 . 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 rims are remounted on the articulator with the new record.

111. • The procedure with intraoral tracer is similar, but as the
tracing is not visible while being made, a thin plastic disc
with a central hole is fixed on the recording plate such
that the hole is placed on the apex of the tracing.
• The patient closes with the tip of the stylus in the hole
and this ensures that the patient closes in centric and
maintains the position while the record is being made.

112. FACTORS OF IMPORTANCE
 Displacement of the record bases may result from pressure if
the central points are off centered.
 If the central bearing device is not used, rims offer resistance
to horizontal movements.
 Tracing not acceptable until a pointed apex is obtained.
 Vertical dimension has to be maintained.
 Equalizes the pressure by distributing the forces throughout
the supporting tissues.
 Allows the mandibular movement to be dictated by the
condyles.

113. NEY’S MANDIBULAR EXCURSION GUIDE
HOME
FORWARD
RIGHTLEFT
BACKWARD
The Ney excursion guide can be used to train the patient to perform mandibular
movements. Movements should be performed in the numerical order labeled in the

114. Pantographic tracings

115. PANTOGRAPHIC TRACING
A graphic record of mandibular movement usually recorded
in the horizontal and sagittal planes as registered by styli on
the recording tables of a pantograph or by means of
electronic sensors (GPT -9)

116.  It is defined as,"A graphic record of mandibular
movement in three planes as registered by the
styli on the recording tables of a pantograph;
tracings of mandibular movement recorded on
plates in the horizontal and sagittal planes"—
GPT

117.  It is a three-dimensional graphic tracer. It is the
most accurate method available to record centric
jaw relation.
 Even eccentric jaw relation can be recorded using
these instruments.
 very sophisticated and are generally not used in
the fabrication of complete dentures.
 This is because complete dentures have a realeff
factor that aids to compensate for the minor
fabrication errors.
 These tracers are generally used for full-mouth
rehabilitation of dentulous patients.

118.  The instrument used to do a pantographic
tracing is called a pantographic tracer. A
pantographic tracer is defined as,"An
instrument used to graphically record one or
more planes paths of the mandibular
movement and to provide information for the
programming of the articulator"— GPT.It
resembles a complicated face-bow.The
surface over which the tracing is done is called
a flag. A stylus (tracing pointer) is present for
each flag.The styli draw tracing patterns on the
flags)

119. PANTOGRAPHIC TRACER
6 FLAGS
4 FLAGS LOCATED
PERPENDICULAR
TO ONE ANOTHER
NEAR THE
CONDYLES.
ADJACENT TO THE
RIGHT CONDYLAR
GUIDANCES.
ADJACENT TO
LEFT CONDYLAR
GUIDANCES.
2 FLAGS NEAR
ANTERIOR
REGION
locatethe actual
(true) hinge axis.
record the
anteroposterior
movements.

122.  Gothic arch tracing are consistent as compared to
wax registration method in good and flat ridges.
 In flabby ridges tracings are not consistent. wax
registrations are more consistent.
Gysi, A., DDS, Practical Application of Research Results in Denture
Construction. JADA. 1929; 16:199-223.

123. Other methods of recording the
centric jaw relation
 Making the rims contact fairly
and evenly in the mouth at the
desired vertical relationship.
This usually makes the
mandible close at centric
relation.
 Strips of celluloid (or) paper are
placed between the rims and
pulled out. The patient is asked
close and restrain the celluloid
from slipping away. While doing
so the patient's mandible
involuntarily goes to centric
relation.

124.  Softened wax may be
placed on the
mandibular occlusal
rim and the patient is
asked to bite in
centric relation.
 Conical blocks of
wax can be made on
the mandibular record
base and the patient
is asked to close on
them at centric
relation

125. IV.RADIOGRAHIC METHODS
 Pyott and Schaeffer used cephalometric radiographs to
record CR and VDO but this method never gained
widespread usage.

126. CR HAS NO FUNCTION !?!
 CR is considered as terminal position in act of
mastication but it does not directly contribute to
mastication.
 In reality teeth do not come in contact during
chewing.
 Thompson stated that a portion of food bolus is
present between the cusps during mastication.

127. INFLUENCE OF CIRCADIAN PERIODICITY ON
REPRODUCIBILITY OF CENTRIC RELATION
RECORDS OF EDENTULOUS PATIENTS
 SHAFAGH et al showed that the position of mandibular
condyle in centric relation for dentulous patients was different
when evaluated in the morning and again at night
 The positional changes in the centric relation records of the
edentulous patients in a study demonstrated a circadian
effect, which could be viewed as similar to the soft tissue and
denture fit changes.
George H. Latta J Prosthet dent. 1992;68:780

128.  Another study evaluated the effect of circadian periodicity on the
reproducibility of centric relation records for edentulous patients.
Circadian physiologic changes can have an effect on the fit of
complete dentures and on the occlusion of complete dentures.
The author suggests fabricating complete dentures during the
middle of the day could help by averaging out theses circadian
effects.
Latta GH Jr., Influence of circadian periodicity on reproducibility of centric
relation records for edentulous patients. J Prosthet Dent. 1992;68(5):780-3.

129. CONCLUSION
 As time and technology advances better
techniques are developed; but for
incorporating this techniques to everyday
practice techniques need to be simplified.

130. REFERENCES
 Zarb GA,Bolender CL Prosthodontic treatment for edentulous
patients 12th edition.
 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.

131.  Swenson’s complete dentures Boucher editor 5th edition.
Granger,E.R:Centric relation. J PROSTHET DENT. 1952; 2:160.
 Winkler’s Essentials of complete denture prosthodontics 2nd edition.
 Brill,N.:. Reflexes,registrations,and prosthetic therapy. J PROSTHET
DENT; 1957; 7:341.
 Sheppard,I.M.:The bracing position,centric occlusion and centric
relation. J PROSTHET DENT. 1959; 9:11.
 Boos,R.H.:Centric relation and functional areas. J PROSTHET DENT.
1959;9:191.
 Trapozzano,V.R.:Occlusal records J PROSTHET DENT. 1955; 5:325.
 Villa,h.:Gothic arch tracing.J PROSTHET DENT. 1959; 9:624.

132.  Yurkstas,A.A,Kapur,K.K.:Factors affecting centric relation records in
edentulous mouths. J PROSTHET DENT. 1964;14:1054.
 Rader,A.F.:Centric relation is obsolete. J PROSTHET DENT. 1955;
5:333.
 Shpuntoff,H.,Shpuntoff,W.:A study of physiologic rest position and
centric position by electromyography. J PROSTHET DENT. 1956;
6:621.
 Kantor,M.E.,et al.:Centric relation recording techniques. J
PROSTHET DENT. 1972; 28:593.
 Lucia,V.O.:Centric relation-theory and practice. J PROSTHET DENT.
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