Centric relation in complete denture

1. FIGURE 7-3 Edentulous mandible in centric relation.
CENTRIC RELATION IN COMPLETE DENTURE
Presenter
Dr. Aastha Subba
Junior Resident
Department of Prosthodontics and Crown-Bridge

2. CONTENTS
➤ Introduction
➤ Theories of Centric Relation
➤ Significance of Centric Relation
➤ Centric Relation Vs Centric Occlusion Vs MIP
➤ Factor influencing Centric relation records
➤ Methods of Obtaining Centric Relation along with critical
analysis of each method
➤ Digital intra-oral Gothic arch tracing
➤ Methods of guiding mandible into centric relation
➤ Conclusion

3. Maxillomandibular relation: any spatial relationship of the
maxillae to the mandible.
Maxillomandibular relationship record: a registration of any
positional relationship of the mandible relative to the maxillae;
these records may be made at any vertical, horizontal, or lateral
orientation; syn, JAW RELATION RECORD
GPT-9
INTRODUCTION

4. ➤ Maxillo-mandibular relations can be recorded as:
A. Orientation Jaw relation
B. Vertical Jaw relation
C. Horizontal Jaw relation
➤ Centric relation
➤ Eccentric relation

5. 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 un-strained, physiologic,
maxillomandibular relationship, the patient can make vertical,
lateral or protrusive movements; it is a clinically useful,
repeatable reference position.”
GPT-9

6. 1. The disk is properly aligned on both condyles.
2. The condyle-disk assemblies are at the highest point possible
against the posterior slopes of the eminentiae.
3. The medial pole of each condyle-disk assembly is braced by bone.
4. The inferior lateral pterygoid muscles have released contraction
and are passive.
5. The TMJs can accept firm compressive loading with no sign of
tenderness or tension.
The mandible is in centric relation if five criteria are fulfilled:

7. k are properly aligned (Figure 7-7), all loading (compres-
e) forces are directed through avascular, noninnervated
uctures that were designed to accept loading. Sicher,9
in
classic text on anatomy, The Temporomandibular Joint,
2, cites this as proof that the TMJs are load-bearing joints.
GURE 7-7 Note also that around the disk there are vascularized tis-
with copious innervation. If the disk becomes misaligned, the loading
es are directed through highly vascularized and innervated tissues that
ond with pain or discomfort. This is why load testing of the TMJs is an
ortant step in determination of centric relation. This is one of the rea-
the TMJs are not in centric relation if they cannot accept firm loading
complete comfort.
C
It is a mistak
placement of the
consistent experi
often the trigger
In fact, some of t
sult from deflect
loose interfering
relation to maxi
many less than s
cause minute inte
perfecting any o
!
FIGURE 7-17 Medial pole bracing in line with internal pterygoid mu
cle contraction establishes the midmost position at centric relation.

8. THEORIES OF CENTRIC RELATION
Muscle Theory
Ligament Theory
Osteofiber Theory
Meniscus Theory

9. ny between the occlusion and the TMJs
es must be displaced from centric relation to
mum intercuspation, the inferior lateral ptery-
must contract to move the mandible to the po-
ximum intercuspation. Note that the condyles
ed down as they are pulled forward. What ap-
n ideal Class I occlusal relationship is actually
muscle incoordination with a potential for oc-
e, muscle pain, or disorders in the intracapsular
the TMJ.
ated muscle function
MUSCLE THEORY
defense reflex
the external pterygoid muscles
contract
halt the jaw every time the condyles or
the interarticular discs approach the
posterosuperior depths of the glenoid
fossae.

10. LIGAMENT THEORY
➤ Ferrein was the first to present the ligament theory.
➤ He found out that when the temporomandibular
ligaments, become tense they determine the limits of
the retrusive movement.
➤ Ligaments bind the elements of the articulations,
limit their possibilities of movement, and are also
capable of determining terminal border positions.

12. ➤ retrusive terminal stop is formed by the soft tissues of
the posterior part of the roof of the glenoid fossa.
OSTEOFIBER THEORY

13. MENISCUS THEORY
➤ the discs, with the retromeniscal fibrous tissues, function as
buffers, thus stopping the retrusive condylar movements by
fitting exactly between the bony surfaces.
olume 26
Number 6
Centric relation and condylar mouement 585
Fig. 4. The temporomandibular articulation in centric relation, sagittal section (semischematic).
(I) Condyle, (2) compact disc, (3, 3’) external pterygoid muscle, (4) temporal bone,
(5) upper articular cavity and (5’) its posterior fold, (6) fib rous posterior disc and (6’) fibrous
anterior disc, (7) retroarticular fibrous tissue, (8) lower cavity and (8’) its anterior fold,
(9) external acoustic conduct, (10) parotid gland, (:I) superficial temporal artery, (22)
auriculotemporal nerve, (I 3) cortex.
Volume 26
Number 6
Centric relation and condylar movement
Fig. 7. Sagittal section of the temporomandibular articulation represented in Fig. 4,
pulsive gliding position. See Fig. 4 for the rest shape of the disc, cavities, and pre- and
articular tissues. Line from center of condyle backward shows condylar path. An a
separation is shown between the fascicles of the external pterygoid to show that the
one is descended. (A) Retroarticular tissues are unfolded; (B) posterior fold of upper
has disappeared; (C) posterior propulsive fold of lower cavity is initiated; (D) disc a

14. Why Centric Relation?

15. ➤ Centric relation is the horizontal reference position of
the mandible
➤ can be routinely assumed by edentulous patients
under the direction of the dentist.
➤ Reproducible, repeatable and recordable.
➤ an accurate centric relation record will orient the lower
cast to the opening axis of the articulator in the same
relation- ship as the patient’s mandible relates to his/
her opening axis.

17. ➤ Centric Occlusion: the occlusion of opposing teeth
when the mandible is in centric relation; this may or
may not coincide with the maximal intercuspal position.
➤ Maximal Intercuspal Position (MIP): the complete
intercuspation of the opposing teeth independent of
condylar position.

18. In the natural dentition (in about 90 percent of the
population), MIP is usually located anterior to CR,
the average distance being 1-1.25mm.
68 PART I Functional Anatomy
ICP
CR
A

19. CENTRIC SLIDE: movement of the mandible while in
centric relation from initial occlusal contact into
maximum intercuspation

20. During construction of complete dentures, maximum
intercuspation position coincides with centric
relation mainly because:
➤ The edentulous patient cannot control mandibular
movements or avoid deflective occlusal contacts in CR
in the same manner as the dentulous patient.

21. RELATION OF VERTICAL DIMENSION AND CENTRIC RELATION
➤ Vertical dimension is defined as the amount of separation
between the maxilla and mandible in a frontal plane.
➤ is determined by the repetitive contracted length of the elevator
muscles.
➤ Any alteration in the Vertical dimension results in the strain in
the Temporo-mandibular joint.

22. hapter 13 Vertical Dimension 125
A
B
If there are no deflective occlusal interferences that require
acement of the TMJs from centric relation to achieve maxi-
ion, the vertical dimension at (A) will stay constant. If you
ical dimension, it will always revert back to this dimension
ng restored or equili-
at the harmonious re-
r disturbed by impru-
mension.
SITION
ENSION
dimension is located
is the repetitive con-
s that determines the
andible. That, in turn,
ting teeth contact and
rces are neutralized
with a downward dis-
a-to-angle dimension
FIGURE 13-11 If there are no deflective occlusal interfere
downward displacement of the TMJs from centric relation
mum intercuspation, the vertical dimension at (A) will stay
increase the vertical dimension, it will always revert back t
at the anterior teeth as the muscles close the bite back to w
A
B
FIGURE 13-12 If the vertical dimension of the anteri
achieved by downward, forward displacement of the condy
relation, it is at this jaw relationship that muscle length (B
VDO. Note the upward movement at the front of the m
condyles move down. The pivot point is usually at the mos

23. FACTORS INFLUENCING CENTRIC RELATION RECORDS
➤ The resiliency of the supporting tissues
➤ The character of the pressure applied in making the recording.
➤ The stability of the recording bases.
➤ The temporomandibular joint and its associated
neuromuscular mechanism.
➤ The technique used in making the recording and the associated
recording devices used.

24. ➤ The skill of the dentist.
➤ The health and cooperation of the patient.
➤ The maxillomandibular relationship.
➤ The posture of the patient.
➤ The size and position of the tongue
Yurkstas AA, Kapur KK. Factors influencing centric relation records in
edentulous mouths. J Prosthet Dent 2005;93:305-10.

25. RECORDING CENTRIC
RELATION IN
EDENTULOUS PATIENTS

26. METHODS TO RECORD CENTRIC RELATION
Physiological Methods
➤ Tactile or Inter-occlusal check
record method
➤ Pressure-less method
➤ Pressure method
Radiographic methods
Graphic methods
➤ Arrow point tracing
Intraoral
Extraoral
➤ Pantograph
Functional Method
➤ Needleshouse method
➤ Patterson method

27. I. PHYSIOLOGIC METHOD
1. Tactile or inter-occlusal check record method
➤ It is the oldest type of Centric relation record.
➤ Earlier obtained by simply placing a thermoplastic material,
between the edentulous ridge and having the patient close
into the material.
➤ This was known as the “MUSH”, “BISCUIT”, or “SQUASH”
BITE.

28. ➤ Waxes
➤ Impression compound
➤ Zinc Oxide Eugenol
➤ Impression plaster
Material used for inter-occlusal record

29. INDICATIONS
➤ Abnormally related jaws.
➤ Supporting tissues that are excessively displaceable.
➤ Large awkward tongue.
➤ Uncontrollable or abnormal mandibular movements.
➤ Check the occlusion of the teeth in existing dentures.

30. PROCEDURE
➤ This method requires two steps
1. tentative records using occlusion rims attached to
accurate stable record bases.
2. interocclusal check records with the teeth arranged
for try in.

32. ➤ Involves guiding the mandible in CR with the maxillae
then making a record of the relationship of the two
occlusion rims to each other.
➤ Advantage - minimal displacement of the recording
bases.
➤ To index or seal the occlusal rim nick and notch
method or Stapler pin method can be used.
2. Pressure-less/Static method.

33. NICK AND NOTCH METHOD

34. STAPLER PIN METHOD
➤ Stapler pins are used to seal
the occlusal rims after the
centric relation are being
registered.
➤ Limitation: Centric relation
record cannot be verified.

35. ➤ Once the vertical dimension is established, the upper occlusal
rim is inserted into the patient’s mouth.
➤ The lower occlusal rim is fabricated of excess height.
➤ Entire lower occlusal rim is softened in a water bath and
inserted carefully into the patient’s mouth.
➤ Patient is guided to close his mouth in centric relation.
➤ After the patient closes his mouth till the pre-determined
vertical dimension, both the occlusal rims are removed,
cooled and articulated.
3. Pressure method.

36. CRITICAL ANALYSIS
• Trapozzano stated that the wax “CHECKBITE METHOD”
is the technique of preference in recording and checking
centric relation.
• Schuyler observed that if the recording medium was not of
uniform density and viscosity, uneven pressures would be
transmitted to the record bases which would cause a
disharmony of occlusion.

37. • Gysi performed this method on manikins and never got
the same recording twice with wax or compound. He
concluded that the uneven cooling of the material
produced distortion.
• Simpson felt that wax records were unscientific and
always carry with them the fallacy of guess.

38. II.FUNCTIONAL METHOD OR CHEW-IN METHOD
These methods utilize the functional movements of the
jaws to record the centric relation.
Two methods which uses this principle are
➤ Needle House method
➤ Patterson’s method

39. ➤ It uses impression compound occlusal rims with four metal
styli placed in the maxillary rim in the premolar and molar
areas.
➤ When the patient moves his mandible, the styli on the
maxillary rim will create a marking on the mandibular rim.
➤ After movements of mandible is completed, a diamond-shaped
pattern is formed.
➤ The posterior most point of this diamond pattern indicates the
centric relation.
1. Needle-House method

40. B- Patterson Technique
In this method, a trench made along the length of occluding part of the mandibul
A mixture of pumice and dental plaster with ratio 1:1 is loaded into the trench

41. ➤ A trench made along the length of occluding part of the
mandibular wax rim.
➤ A mixture of carborundum and dental plaster is loaded into
the trench.
➤ When the patient moves his mandible, compensating curves
on the mixture is formed with decrease in the height of the
mixture.
2. Patterson method

42. ➤ The patient asked to continue with these movements until
a predetermined vertical dimension obtained.
➤ Finally, the patient asked to retruded his jaw and the
occlusal rims fixed with metal staples.
ure 9 PROSTHODONTICS Dr. Firas Abdulameer

43. CRITICAL ANALYSIS
➤ Forces which can dislodge the record bases occur in any
method, that requires the mandible to move into eccentric
jaw position with the recording medium in contact……. The
functional methods of recording Centric Relation requires
very stable record bases.

44. ➤ The displaceable basal seat tissues, the resistance of the
recording mediums, and the lack of control of equalized
pressure in the eccentric relations contribute to inaccuracy
in these methods.
➤ Patients not only must have good neuromuscular
coordination but also must be capable of following
instructions if accurate records are to be obtained.

45. III. GRAPHIC METHOD
➤ Graphs or tracing are used to record centric relation.
➤ Two types
Arrow point tracing
Pantographs

46. ARROW POINT TRACING
➤ It records a tracing of mandibular movements in one
plane.
➤ Also known as Gothic arch tracing, Stylus tracing, Centric
bearing tracing and Needle point tracing.
➤ First proposed by Hesse and later popularized by Gysi.

47. ➤ The general concept is that a pen-like pointer is
attached to one occlusal rim and a recording plate is
placed on the other rim.
➤ The plate is 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.

48. Intra-oral graphic method

49. ➤ The apex of a properly made tracing presumably indicates
the most retruded relation of the mandible to the
maxillae from which lateral movements can take place.

50. Arrow Point Tracing Method
Intra-oral Tracing
and devices
Extra-oral Tracing
and devices
Hight tracer
Sears tracer
Phillips extraoral tracer
Coble tracer
Swiss dent ball bearing
bite tracer
Microtracer

51. ➤ Central bearing device.
A. Central bearing point
B. Central bearing plate
➤ Stylus /Needle point
➤ Tracing table
PARTS OF TRACERS
not required in
intra-oral
tracers.

52. ➤ Central bearing point
triangular plate of metal.
metal pointer is present in the center of the triangle.
Pointer can be adjusted in height
usually attached to the mandibular occlusal rim.
PROSTHODONTICS

53. ➤ Central bearing plate
triangular metal piece
usually attached to maxillary occlusal rim.
The plate provides an even surface on which the bearing
point slides as the jaw moves.
PROSTHODONTICS Dr. Firas Abd

54. ➤ Stylus and tracing table
In intra oral devices central bearing device will serve as
stylus and tracing table.
In extra oral tracing devices additional stylus and tracing
table have to be attached to obtain graphic record.

55. ➤ In the intraoral method, stylus is fixed to mandibular arch
and tracing platform is attached to maxillary arch.
➤ The tracing platform is usually coated with coloured
contrasting media.
➤ The vertical height is maintained by the stylus and a gap
of 3mm is maintained between the occlusal rims.
Intra-oral tracing

56. PROSTHODONTICS Dr. Firas
Intraoral tracing assem

57. Intraoral tracing
aoral tracing

58. ➤ Coble balancer
➤ Swissdent ball bearing bite recorder
➤ Microtracer
Examples of Intra-oral tracers

59. DIGITAL INTRA-ORAL GOTHIC ARCH TRACING
The system consists of three parts namely
A. intraoral sensor pad,
B. extraoral digitizer circuit MAX 232 and
C. a computer display with analysis software MATLAB®
programme (MATLAB 7.11 R2010b).

60. The Journal of Indian Prosthodontic Society | Volume 19 | Issue 2 | April-June 2019
Figure 1: Intraoral tracing board attached to the digitizer
Figure 3: Illustration of digital Gothic arch system
Fig
the

61. ➤ The principle behind this technique is, when the stylus
comes in contact with intra-oral digital tracer, co-
ordinates (X, Y) are obtained on the laptop
➤ Changes in Y coordinates represented movement in
anteroposterior direction while changes in X co-
ordinates were associated with lateral movement over
tracing board.

62. g
],
al
space is observed between the occlusal rims to ensure free
movementof stylusovertracingpadwithoutanyobstruction
or contact between opposing occlusal rims.
Figure 6: Maxillary occlusal rim with the central bearing device
(intra‑oral view)
Figure 8: Gothic arch tracing
182 The Journ
Figure 5: Vertical jaw relation
Figure 7: Mandibular occlusal rim with mounted tracer board on central
bearing device (intra‑oral view)
Figure 9: MATLAB®
software showing Gothic arch tracing and
coordinates of Gothic arch apex
Figure 5: Vertical jaw relation
Figure 7: Mandibular occlusal rim with mounted tracer board on central
bearing device (intra‑oral view)
Figure 6: Maxillary occlusal rim with the central bearing device
(intra‑oral view)
Figure 8: Gothic arch tracing
ournal of Indian Prosthodontic Society | Volume 19 | Issue 2 | April-June 2019
Figure 6: Maxillary occlusal rim with the central bearing device
(intra‑oral view)
Figure 8: Gothic arch tracing
Figure 10: Gothic arch tracing saved by software

63. ➤ Intraoral digital tracing method to record horizontal
mandibular position is a better technique compared to the
conventional method in relation to visualization and accuracy.
➤ The horizontal mandibular position recorded in supine
position gives more accurate readings as compared to upright
position.
Abbad NB, Srivastava R, Choukse V, Sharma V. Validity and reliability of intraoral conventional tracer
and intraoral digital tracer in different positions for recording horizontal jaw relation in edentulous
patients. J Indian Prosthodont Soc. 2019 Apr-Jun;19(2):159-165.
Conventional intra-oral Vs Digital
intra-oral Arch tracing

64. ➤ both the tracing platform and stylus are placed extra-orally.
➤ Central bearing point —- mandibular occlusal rim
➤ Central bearing plate—- maxillary rim.
➤ Both the plates are fixed mutually parallel.
➤ The occlusal rims and the attached tracing assembly are kept in
the mouth and the patient is asked to make eccentric
movements.
Extra-oral tracing

67. ➤ Hight tracer
➤ Sears tracer
➤ Philips tracer
Examples of Extra-oral tracers

68. Gerber stated six different types of tracing:
A. classical pointed form,
B. classical flat form,
C. weak tracing,
D. asymmetrical form,
E. miniature form and
F. tracing with vertical line beyond arrow point
Evaluating gothic arch tracing

69. Other than the previously mentioned Gothic arch tracing
forms, based on the presence or absence of teeth, they can
be further divided into:
➤ Double Arrow Point,
➤ Interrupted Gothic Arch, and
➤ Atypical Form.

70. the apex obtained is well defined,
with symmetrical left and right lateral components.
The mean angle obtained by Gothic arch tracing should be
120 degrees.
depicts the undisturbed movement of the condyle in the fossa
and slope of eminence.
Jemds.com
Classical pointed

71. It has obtuse left and right lateral tracings.
Gothic arch angle more than 120°.
This type of tracing signifies a marked lateral movement of
the condyle in the fossa.
Jemds.com
Classical pointed arrowhead form: the apex obtained is well defined, with
symmetrical left and right lateral components. The mean angle obtained
by Gothic arch tracing should be 120 degrees indicating the health of
Temporomandibular joint without interferences in the path of condylar
movement and balanced neuromuscular coordination. The bilateral
symmetrical form of arrowhead depicts the undisturbed movement of the
condyle in the fossa and slope of eminence.
Classical flat arrowhead form: It is almost similar to classical arrow
point except that the tracing obtained is more than 120°. It has obtuse
Small or miniature ar
arrowhead point, howe
limited mandibular mo
neuromuscular coordina
improper seating of record
edentulous for longer per
Classical flat arrow-head form

72. Similar to the classical arrowhead point, however, the tracing
obtained is small due to
➤ limited mandibular movement.
➤ restricted neuromuscular coordination
➤ improper seating of record bases.
It is also an indication of a being of edentulous for longer
period of time with inhibition in mandibular movements.
emds.com Review
lassical pointed arrowhead form: the apex obtained is well defined, with
ymmetrical left and right lateral components. The mean angle obtained
by Gothic arch tracing should be 120 degrees indicating the health of
Temporomandibular joint without interferences in the path of condylar
movement and balanced neuromuscular coordination. The bilateral
ymmetrical form of arrowhead depicts the undisturbed movement of the
condyle in the fossa and slope of eminence.
Small or miniature arrowhead point: Similar to the cl
arrowhead point, however, the tracing obtained is sma
limited mandibular movement. This might be due to re
neuromuscular coordination or mandibular movements
improper seating of record bases. It is also an indication o
edentulous for longer period of time with inhibition in m
movements
Miniature form:

73. The arrow point obtained is blunted and not sharp.
This is indicative of a weak retrusive movement and the
patient has to be trained well
the tracing should be repeated till a definite arrow point is
obtained.
by Gothic arch tracing should be 120 degrees indicating the health of
Temporomandibular joint without interferences in the path of condylar
movement and balanced neuromuscular coordination. The bilateral
symmetrical form of arrowhead depicts the undisturbed movement of the
condyle in the fossa and slope of eminence.
Classical flat arrowhead form: It is almost similar to classical arrow
point except that the tracing obtained is more than 120°. It has obtuse
left and right lateral tracings. This type of tracing signifies a marked
lateral movement of the condyle in the fossa.
limited mandibular mo
neuromuscular coordina
improper seating of record
edentulous for longer per
Extended arrowhead
mandibular movement ex
The guidance provided to m
movement of the lower jaw
is also sometimes an artef
record bases or backward
rim while removing them f
repeated to confirm the er
bases and also
Double Arrow Point
It is a record with do
caused due to habitu
Weak or blunted arrowhead form

74. 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.
Classical flat arrowhead form: It is almost similar to classical arrow
point except that the tracing obtained is more than 120°. It has obtuse
left and right lateral tracings. This type of tracing signifies a marked
lateral movement of the condyle in the fossa.
Weak or blunted arrowhead form: The arrow point obtained is
blunted and not sharp the tracing should be repeated till a definite
arrow point is obtained. The patient has to be trained well
Extended arrowhead
mandibular movement e
The guidance provided to
movement of the lower ja
is also sometimes an arte
record bases or backwar
rim while removing them
repeated to confirm the e
bases and also
Double Arrow Point
It is a record with d
caused due to habi
retruded centric r
neuromuscular movem
and guided well.
Interrupted Gothic A
Break-in continuity of
obtained, due to interf
caused due to touchin
lateral movements.
Atypical Form
The component does n
the lateral paths. This
of a faulty Muscular p
like bruxism. It is a
Asymmetrical arrowhead form

75. The protrusive path of mandibular movement extended beyond the
apex of the Gothic arch.
usually occurs when the operator or the patient forcibly retrudes the
mandible.
It is also sometimes an artifact caused by backward dislodgement of the
mandibular occlusal rim while removing them from the mouth.
The registration should be repeated to confirm the error after correct
positioning of the record bases and also properly guiding the mandible.
Extended arrowhead more dorsally

76. well defined, with
n angle obtained
g the health of
path of condylar
. The bilateral
movement of the
e.
classical arrow
20°. It has obtuse
nifies a marked
ssa.
Small or miniature arrowhead point: Similar to the classical
arrowhead point, however, the tracing obtained is small due to
limited mandibular movement. This might be due to restricted
neuromuscular coordination or mandibular movements or due to
improper seating of record bases. It is also an indication of a being of
edentulous for longer period of time with inhibition in mandibular
movements
Extended arrowhead more dorsally: The protrusive path of
mandibular movement extended beyond the apex of the Gothic arch.
The guidance provided to move mandible might be strained retrusive
movement of the lower jaw either by the patient or by the operator. It
is also sometimes an artefact caused by the forward displacement of
record bases or backward dislodgement of the mandibular occlusal
rim while removing them from the mouth. The registration should be
repeated to confirm the error after correct positioning of the record
bases and also properly guiding the mandible.

77. Double Arrow Point
caused due to habitual and retruded centric relation
also seen when vertical dimension is altered during
registration
patients should be trained and guided well.

78. Interrupted Gothic Arch
There is break-in continuity of path of a tracing
due to interference or obstruction in movement caused due to
touching of heels of occlusal rims during lateral movements.

79. Atypical Form
The component does not meet at the apex but on one of the
lateral paths.
seen in very old edentulous patients, who are using complete
denture with incorrect centric relation.

80. ➤ Arrow point will be directed towards the patient in intraoral
tracing where as in extraoral tracing it will be directed away
from the patient.
➤ The intra-oral tracings cannot be observed during the tracing,
whereas the extraoral tracings are visible while the tracing is
being made. Hence, the patient can be directed and guided
more intelligently during the mandibular movements.
Intra-oral vs Extra-oral gothic arch Tracing

82. ➤ In extra-oral tracing, the stylus can be observed in
the apex of the tracing during the process of
injecting plaster between the occlusion rims, any
unwanted movement of the mandible is prevented
thereby maintaining the accuracy of the record.
➤ Intra-oral tracing is more accurate since it is located
nearer to condylar rotational axis and also the oral
musculature remains passive during recording.

83. ➤ Gysi concluded that his tracing technique had only a 5-degree
error, whereas wax and compound bites had a 25-degree error.
➤ According to Hanau, the Gysi tracing was satisfactory to check
records, but its universal usage was not good.
➤ Granger insisted that needle point tracing is not a reliable
means of determining centric relation, since it is recorded in
horizontal plane only.
CRITICAL ANALYSIS

84. The National Society of Denture Prosthetics reported
that “the use of the needle point tracing device for the
purpose of determining and checking centric jaw relation
is recommended as being both scientific and practical.
This society recognizes no other means of verifying
centric jaw relationships.”

86. FIGURE 7-3 Edentulous mandible in centric relation.
Resource Faculties
Prof. Dr R.K. Singh
Prof. Dr Pramita Suwal
Dr Prakash K. Parajuli
Dr Arati Sharma
Dr Indra K. Limbu
Dr Bishal B. Basnet
Dr. Meena Mishra
CENTRIC RELATION IN COMPLETE DENTURE
Presenter
Dr. Aastha Subba
Junior Resident
Department of Prosthodontics and Crown-Bridge

87. METHODS TO RECORD CENTRIC RELATION
Physiological Methods
➤ Tactile or Inter-occlusal check
record method
➤ Pressure-less method
➤ Pressure method
Radiographic methods
Graphic methods
➤ Arrow point tracing
Intraoral
Extraoral
➤ Pantograph
Functional Method
➤ Needle house method
➤ Patterson method

88. PANTOGRAPHIC TRACING

89. ➤ A graphic record of mandibular
movement in three planes as
registered by the styli on the
recording tables of a pantograph.
➤ most accurate method to record
centric jaw relation.
➤ not generally used in fabrication of
complete dentures.
A

90. ➤ It resembles a complicated
face-bow.
➤ The surface over which the
tracing is done is called a flag.
➤ A stylus is present for each flag
which draw tracing patterns on
the flags.
Pantographic tracer
62 PART I Planning and Preparation
FIGURE 2-34 ■ The Stuart instrument, used to make pantographic
recordings. (Courtesy Drs. R. Giering and J. Petrie.)
W
Pantographic Recordings. Fully adjustable articula-
tors are usually programmed on the basis of a panto-
graphic recording (Fig. 2-34). Jaw movements are
registered by directional tracings on recording plates.
The plates are rigidly attached to one jaw, and the record-
ing styli are attached to the other. A total of six plates are
needed to achieve a precise movement record of the man-

91. ➤ A pantographic tracer has six flags:
Two flags located perpendicular to one another near the
condyles. They locate the actual/ true hinge axis.
Two flags are placed in the anterior region and they record the
anteroposterior movement.
FIGURE 2-34 ■ The Stuart instrument, used to make pantographic
recordings. (Courtesy Drs. R. Giering and J. Petrie.)
P
N
N
N
N
W
W
W
W P
P
P
consists of upper and lower bows that record and measure
mandibular movements and has been shown to provide
valid and reliable measures of condylar determinants.31
Stereograms. Another approach to reproducing pos-
terior condylar controls is to cut or mold a three-
dimensional recording of the jaw movements. This
“stereogram” is then used to form custom-shaped fossae
for the condylar heads.
Anterior Guidance. Border movements of the mandi-
ble are governed by tooth contacts and by the shape of
the left and right temporomandibular joints. In patients
with normal jaw relationships, the vertical and horizontal
overlap of anterior teeth and the lingual concavities of
the maxillary incisors are highly significant during
protrusive movements. In lateral excursions, the tooth

92. CEPHALOMETRIC RECORDINGS METHOD
➤ Pyott and Schaeffer described the use of cephalometrics to
record centric relation.
➤ These radiographs were used to determine centric relation
and the appropriate vertical dimension of occlusion.
➤ This practice, however, never gained widespread usage.

93. GUIDING MANDIBLE TO
CENTRIC RELATION

94. The following instructions can assist the patient in
retruding the mandible:
1. Instruct the patient by saying, “Let your jaw relax, pull
it back, and close slowly and easily on your back teeth.”
2. Instruct the patient by saying, “Get the feeling of
pushing your upper jaw out and closing your back teeth
together.”

95. 3. Instruct the patient to protrude and retrude the
mandible repeatedly while holding his or her fingers
lightly against the chin.
4. Instruct the patient to turn the tongue backward
toward the posterior border of the upper denture.
5. Instruct the patient to tap the occlusion rims or back
teeth together repeatedly.

96. Mandibular Guidance Method
Patient Guided
(Active)
Operator Guided
(Passive)
➤ Schuyler technique
➤ Physiological technique
➤ Gothic arch tracing
➤ Myo-monitor
➤ Chin-point Guidance
➤ Three- finger Chin-point
Guidance
➤ Bi-manual manipulation Method
➤ Anterior Guidance Method
➤ Power Centric Method

97. ➤ Patient is asked to place the tip of the tongue to the back
of the palate and close the mouth on the softened wax
with light pressure.
➤ This technique can also be used, with wax rims, for the
edentulous patient
rence in record-
and upright
perator's guid-
poromandibular
sion will result
protrusion and
gs. Psychologi-
ill also increase
mber of teeth,
e form of eden-
the stability of
d thus the qual-
& RCP
dance is to help
n the glenoid fos-
is in a consistent
ndibular closure
axis. Mandibular
the glenoid fossae.37 However, too much
force is detrimental as the mandible flex-
es38,39 about the horizontal plane.
Patient-guided recording of RCP
Schuyler technique40 (Fig. 3)
This quick and simple technique involves the
patient placing the tip of the tongue to the
back of the palate and closing into a horse-
shoe of softened wax with light pressure.
formity of sof
control over t
any tooth con
appropriate fo
Fig. 3 Clinical view of RCP registration using the
Schuyler technique

98. ➤ To establish the physiologic centric relation, blocks of soft wax
are placed on the lower occlusion rim in the bicuspid and first
molar regions.
➤ Both occlusion rims are inserted in the mouth, and the patient
is requested again to swallow several times.
➤ The centric relation obtained is then transferred to the
articulator for establishing centric occlusion.
Swallowing method/Physiologic Method
Shanahan TE. Physiologic jaw relation and occlusion of complete dentures.
J Prosthet Dent 1955;5:319-24

99. Fig. 2. Physiologic vertical dimension is recorded by an
anterior record made in a cone of soft wax. Repeated
swallowing of saliva establishes the height of the wax at the
physiologic vertical dimension.
Fig. 3. Physiologic centric relation record is made in soft wax
at the physiologic vertical dimension.
Fig. 5. Thir
premature
wax, which

100. ➤ The myo-monitor is an electrical jaw muscle stimulating
device which achieves muscle relaxation and produce a
neuromuscular mandibular position by stimulating the
motor branches of V and VII cranial nerve.
➤ An example is the J-4 Muscle Stimulator (Myotronics-
Noramed Inc, USA).
Myo-monitor
4. MYO MONITOR
It is an electrical jaw muscle stimulating device whic
reputed to achieve muscle relaxation producing a
neuromuscular mandibular position.

101. ➤ The patient's mandible is guided
into a hinge closure by the thumb
and index finger of the operator.
➤ The risk with this method is the
ease with which the condyles can
be over-retruded.
Chin-point Guidance

102. Chapter 9 Determining Centric Relation 77
PROCEDURE Using bilateral manipulation to find and verify centric relation or adapted
centric posture—cont’d
Step three: After the head is stabilized, lift the patient’s chin
again to slightly stretch the neck. Be sure you are comfortably
seated, with the patient low enough to allow you to work with your
forearm approximately parallel to the floor.
Step four: Gently position the four fingers of each hand on the
lower border of the mandible. The little finger should be slightly
behind the angle of the mandible. Position the pads of your fingers
so they align with the bone, as if you were going to lift the head.
Keep all four fingers tightly together.
Step five: Bring the thumbs together to form a C with each
hand. The thumbs should fit in the notch above the symphysis. No
pressure should be applied at this time. All movements should be
made gently.
Chapter 9 Determining Centric Relation 7
PROCEDURE Using bilateral manipulation to find and verify centric relation or adapted
centric posture—cont’d
Step three: After the head is stabilized, lift the patient’s chin
again to slightly stretch the neck. Be sure you are comfortably
seated, with the patient low enough to allow you to work with your
forearm approximately parallel to the floor.
Step four: Gently position the four fingers of each hand on the
lower border of the mandible. The little finger should be slightly
behind the angle of the mandible. Position the pads of your fingers
so they align with the bone, as if you were going to lift the head.
Keep all four fingers tightly together.
Step five: Bring the thumbs together to form a C with each
hand. The thumbs should fit in the notch above the symphysis. No
Bi-manual manipulation method
ulation to find and verify centric relation or adapted
in up.
he op-
sier to
ncy of
gh so
entists
ead in
n that
re dif-
kward
an be
ilized
g ma-
ch
No
be
Continued

103. to find and verify centric relation or adapted
FIGURE 9-1 Testing position and alignment of each con
begin with gentle loading. B, Thumbs and fingers load the
ward and forward direction.
B

104. WAX BALL TECHNIQUE
➤ A technique to register the CR which is time saving and easier to
understand by clinicians and patients as well.
Sushma R, Roy MS, Sanyal PK, Joshi A, Vande A, Kore AR. A clinical comparative study to assess the efficacy of a new
centric registration technique with a conventional technique. J Indian Prosthodont Soc. 2019;19(4):290-295.

106. ➤ This newly designed technique was compared with the
Dawson's bimanual method and it was found that:
the time consumption was statistically less compared
to the Dawson's bimanual technique;
both the techniques were found to be equally
accurate.
this technique can be easily explained to the patient.
Sushma R, Roy MS, Sanyal PK, Joshi A, Vande A, Kore AR. A clinical comparative study to assess the
efficacy of a new centric registration technique with a conventional technique. J Indian Prosthodont Soc.
2019;19(4):290-295.

107. COMPLICATIONS IN RECORDING CENTRIC RELATION
Biologic
Physiologic
Mechanical

108. ECCENTRIC JAW RELATION
➤ any relation of mandible to maxilla other than centric
position.
➤ 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 to the relative movements of the mandible.
➤ The eccentric position to be recorded are protrusive and right
and left lateral.

109. METHODS FOR ECCENTRIC RELATION RECORDS
➤ Functional or chew in methods.
➤ Graphic methods.
➤ Physiological methods (tactile or inter-occlusal
check record method)

110. FUNCTIONAL METHOD

111. GOTHIC ARCH TRACING
➤ After the mandibular cast has been mounted on the articulator in
centric relation, reseat the recording devices in the patient’s
mouth.
➤ Measure a distance of 5-6mm from the apex of the arrow point
tracing on the protrusive tracing and mark this point.
➤ Instruct the patient to protrude until the point of the stylus rests
in the mark point.
➤ Inject quick-setting dental plaster between the occlusion rims,
allow the plaster to harden, and remove the cast from the mouth.

112. ➤ Free the horizontal condylar adjustments on the articulator by
releasing the locknuts.
➤ Raise the incised guide pin about 1/2 inch from the top of the guide
table.
➤ Carefully seat the record bases on the cast. An accurate seating of
both condyles must be secured.
➤ Secure the locknuts with positive finger pressure.
➤ Record the right and left calibrations of the horizontal inclinations
on the plaster mounting. This record is useful if the settings are
accidentally moved.

115. INTEROCCLUSAL RECORD METHOD

116. The eccentric records (protrusive) are made 6mm away
from centric (arrow point) because:
➤ The normal functions are performed within 6mm.
➤ Beyond 6mm, condyles will be positioned too anteriorly
resulting in reduction of horizontal angle while
programming the articulator.

117. LATERAL RELATION RECORD
➤ helps the dentist to maintain the harmony between the
mandibular movements and cusp inclines.
➤ According to Hanau, the setting of a lateral relation by an
anatomic record offers no particular advantages and
recommended the following formula to arrive at an acceptable
lateral indication:
L= H/8+12

119. CONCLUSION
➤ Establishing the Centric relation can be difficult.
➤ It is unknown whether one registration method is better
than another but it is the accuracy and reproducibility of
achieving the centric relation in a given operator's hands
which is probably of greatest importance.
➤ Training in mandibular guidance has been shown to
produce constistency.

120. ➤ Consistently identifying and recording centric
relation pays dividends for both the patient and
operator.
➤ Ultimately the main goal of prosthetic treatment is to
provide patients with an occlusion which is
functional, aesthetic, stable, maintainable and does
not cause discomfort.

121. REFERENCES
➤ A.O Rahn and C.M Heartwell,Textbook of complete dentures,4th edition,1993,Lea
and Fabiger,USA,pp-290-308
➤ Peter E Dawson, Functional occlusion: From TMJ to Smile Design, 2007, Mosby, Inc
➤ Mandibular centricity :centric relation-JPD 2000;83
➤ Yurkstas AA, Kapur KK. Factors influencing centric relation records in edentulous
mouths. 1964. J Prosthet Dent. 2005 Apr;93(4):305-10. doi: 10.1016/j.prosdent.
2004.10.026. PMID: 15798677.
➤ Critical evaluation of methods to record centric jaw relation –journal of indian
prosthodontic society july 2009

122. ➤ Physiologic vertical dimension and centric relation –JPD 2004;91
➤ Centric relation and condylar movement:Anatomic mechanism. JPD1971;vol
26:581-590
➤ A technique for recording centric relation. JPD1964;vol 14:492-505.
➤ Centric relation -theory and practice.JPD1960:vol 10:849-856 17.
➤ Centric relation and functional areas.JPD1959;vol 9:191-196
➤ The Maxillomandibular relationship of centric relation. JPD 1959; vol6:922-
926

123. ➤ Validity and reliability of intraoral conventional tracer and intraoral digital
tracer in different positions for recording horizontal jaw relation in edentulous
patients. J Indian Prosthodont Soc. 2019 Apr-Jun;19(2):159-165. doi:
10.4103/jips.jips_269_18. PMID: 31040550; PMCID: PMC6482625.
➤ 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.
➤ Sushma R, Roy MS, Sanyal PK, Joshi A, Vande A, Kore AR. A clinical
comparative study to assess the efficacy of a new centric registration technique
with a conventional technique. J Indian Prosthodont Soc. 2019;19(4):290-295.