centric relation in complete denture prosthodontics

types of jaw relations in complete denture prosthodontics

1. CENTRIC RELATION
Presented by :
DR. KULDEEP
(13-3-09)

2. Contents
•Introduction
•Chronologyofthechangingdefinitionsonthecondylar
positioninCR
•Definitions
•Features&significanceofCR
•Centricityofcentricrelation
•TwodimensionsofCR
•Anatomicbasisofcentricrelation
•Centricrelationinaloadingposition
•Centricrelationisterminalhingeposition

3. •Character of occlusion in CR
•Concepts in recording CR
•Problems in retruding mandible to CR
•Methods for assisting pt to retrude the mandible
•Methods to record CR
•Critical evaluation of CR recording methods
•Conclusion
•References

4. Introduction
•Inalmostanybookonocclusionandprosthodontics,CRis
thebeginningofthestory.
•CRisthebeginningofocclusion,andalltreatmentmodalities
arebasedonit.
•ResearchinthefieldofCRhasbeencontroversial.Nowhere
indentistryonecanseesomuchdebateandopposingideas
amongscientistsandclinicians.

5. Introduction
•Thischallengeisstillgoingon,andperiodically,someor
otherclinicianpresentsamethodtorecordCR“correctly”or
redefinethismandibularposition.
•Suchmethodshavefundamentaldifferencesbetweeneach
otherbut,surprisingly,theyaimtoachievethesamegoaland
areclaimedtodoso.

6. Introduction
•AlsounusualisthechangethatCRdefinitionshave
undergoneinthepastyears,despitethefactthatthesame
methodsareusedandclaimedtobevalidandcompatible
withrecentdefinitions.
•PerhapsitistheTMJthatadaptsitselftothescientists’
definitioneachtimeitchanges,oristheTMJacceptingany
position?
•Researchhasindicatedthatthepositionistheidealonefor
fixedprosthodonticsandcompletedenturereconstructions,
TMJtherapyandorthodontics.

7. Chronology of the changing definitions
on the condylar position in CR

8. Chronology of the changing definitions
on the condylar position in CR
Year Suggestedby Position
1920 McCollum Rearmost condyle position
1952 Granger Uppermost, rear most
1969 Stuart RUM position
1977 GPT 4 Most posterior position
1977 American Equilibrium
society (AES)
Anterior and superior most position
1978 Celenza Condyle disk assembly
1987 AES AS positionand thinnest avascular position
of disc
1987 GPT 5 New AS position

9. Opinion regarding CR of distinguished researcher
Researcher Opinion
Dawson Maximum intercuspation of teeth should occur when the
condyle disc assemblyare in most superior position
Ash Midmost, uppermost
Gerber Zenith of fossa
Guichet Most superior position
Lucia Condyles should be braced ant-superiorlyagainst the distal
slope of articular eminence
Ramjford Anterior upper position
Boucher Most posterior relation of lower jaw to upper jaw
Posselt Reproducible border hinge position
McCollum Most retruded idle position
Stuart & StallandRear most untranslatedhinge

10. Definitions
JAW RELATION OR MAXILLOMANDIBULAR RELATION:
•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.
(GPT-8)
•Any spatial relationship of the maxillae to the mandible;
anyone of the finite relationship of the mandible to the
maxillae. (GPT-7)

11. Jaw relation can be recorded:
-Orientation relation
-Vertical relation
-Horizontal relation
Centric relation
Eccentric relations
•Protrusive record
•Lateral records

12. Centric relation
•GPT 1
“ the most retrudedrelation of the mandible to the
maxillae when the condyles are in the most posterior
unstrained position in the glenoid fossae from which lateral
movements can be made at any given degree of jaw
seperation “
(1956)

13. •GPT 5
“ a maxillomandibular relationship in which the
condyles articulatewith the thinnest avascularportion of
their respective diskswith the complex in the anterior
superior positionagainst the slopes of the articular
eminences. This position is independent of tooth contact.
This position is clinically discernible when the mandible is
directed superiorly and anteriorly and restricted to a purely
rotary movement about a transverse horizontal axis.
this term is in transition to obsolescence .”
(1987)

14. DIFFERENCES IN GPT DEFINITIONS:
The earlier definition mentions of a most posterior
position of condyles in glenoid fossa, while-the latter definition
speaks of an anterior superior position of condyle against the
slopes of the articular eminence.
The discrepancy between RUM position and anterior
superior position is only approximately
-0.2 mm (Hobo) to 0.3mm (Celenza).
-Theoretically the difference is only on the emphasis on the
condylar position of centric relation.

15. •Orthopedically stable position

16. Significance of Centric Relation
1.The ideal arch to arch relationship and an optimum
functional position of jaws for the health, comfort and
function of the TMJ and musculature.

17. 2.It is a mandibular position where the condyle assembly is
seated in anterior-superior position against the posterior
slope of articulator eminence.

18. 3. Centric relation of mandible is a hinge position. In centric
relation condyles exhibit only pure rotation without any
translation.

19. 4.Mandibular movements return or terminate in centric-------
a reproducibleposition and therefore serves as a reliable
referenceto develop centric relation in artificial dentures.

20. 5. It is a position where upper and lower teeth are braced
against each other during deglutition.
6. It serves as a referenceposition for occlusal reconstruction
in dentulous situations.
7. It is a posterior border position and the
posterior limit of the envelopeof mandibular
motion.

21. Centricity of centric relation
•The term centric relation was derived from the word
‘centre’ or “center oriented relation”.
•Condylar centricity was first proposed by Gysi.
•Later accepted by several authors,
particularly Gerberwho described
it as a “Zenith of the fossa”
relation.

22. Two dimensions of CR-Dual Centric
1.Condylar centric position, is a condyle disc-fossa
eminentia relationship.
2.Mandibular centric position , is a maxillo-mandibular
relationship.

23. •During centric jaw relation position,
Condyles -----------seated in a superior-anterior position
not in a retruded position,
mandible -----------posterior terminal position directed
anterior-superiorly.
•Unless the mandible functions from its terminal position
cannot be a reproducible and consistent position.

24. Anatomic basis of centric relation
•All definitions are topographic(location oriented) –
provide information as to how to secure this position.
•Don’t tell about the importance in prosthodontic
procedures and its effect if not recorded correctly.
•Dawson: “If we were asked to select the one arch to arch
relationship that is most important to comfort, function and
health of the Gnathostomatic system, we would have to say
without reservation, it is the centric relation position of the
mandible”.

25. CR is a loading position
Depending on the loading of the temporomandibular
joint centric relation could be identified as:
a. Passive centric: Seen during
passive closure of jaw in CR
or as projected in the articulator.
b. Power centric: A dynamic
centric observed during
mastication and deglutition.

26. •It has been reported that compressive forces acting on the
joint are relatively high -more than 2.7times that of forces
on the occlusal table.
•When the occlusal surfaces of upper and lower teeth are a
passive contact position in centric relation there is loading
on the joint.

27. •During mastication and deglutition,
•loading progresses

28. •“Buffer space” or “Safe space” present between the
condyle and the fossa which prevented the transmission of
heavy load transfer to the condyle during function.
•It help in minimizing the direct forces on the disc and
protect it from anterior displacement and perforation

29. Glenoid fossa
Criteria for redefining CRof the condyles from RUMto
anterior-superiorposition

30. •Roof of Glenoid fossa ----extremely thin and translucent
in some dry specimens.
•No articular cartilage in the Glenoid fossa, but there are
many minute foramina presumably for the passage of
blood vesssels and nerves.
•The “glenoid space” is occupied by the thickened posterior
zone of articular disc ----------contains blood vessels and
nerves and therefore not suited for function of articulation.

31. •The superior portion of the condylar head is covered with
articular cartilage extending forward over the anterior face
of the condyles and it is designed for stress.
•Similarly, the bony trabecular struts on the curved surface
of the posterior portion of the eminentia are oriented
parallel to the direction of forces.
•Therefore, Celenza felt that the posterior slope rather than
the glenoid fossa is the articular portion of the joint.

32. •The center of the articular disc which is interposed
between the condyle and the posterior slope of the articular
eminence is devoid of nerves and blood vessels, indicating
a stress bearing portion or functioning area of the disc.
•While the non-stress bearing thick periphery of the disc is
rich in blood vessels and nerves

33. CR is a terminal mandibular position
•CR is a baseline position for the termination of mastication
and deglutition.
•Masticatory movements return to CR and originate from
this position.
•Swallowing act takes place in this position.

34. •Therefore it is logical that CR which is a baseline position
for mandibular movements should be a terminal position.
•This is substantiatedfurther by: the gothic arch tracing
does not alter whether one accepts the RUM or A-S centric
position of condyles.

35. Character of occlusion in CR
1.Point centric or the Gnathological centric occlusion
( Lucia , Granger )
CR=CO=MIP
e.g. organic occlusion.

36. 2.Longcentric/Freedomincentric/Areacentric
CR=CO
afreedomisgiventoclosethemandibleeitherintoCR
orslightlyanteriortoitinCOwithasmoothgliding,
withouteffectinganychangeinverticaldimensionof
occlusion.
Panky, Mann --------Long centric
Schuyler -------------Freedom in centric
Beyron ---------------Area centric
Ramfjord -------------Play in centric

37. Concepts and objectives in recording CR
1. Minimal closing pressures-
•So that the tissues 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.
•The uniform contact of the teeth will not stimulate the
patient to clench and relax the closing muscles in periods
between mastication.

38. 2. Heavy closing pressure-
•So that the 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 tissues as would exist when heavy
closing pressures are applied on the dentures.
•Thus the occlusal forces will be evenly distributed over the
supporting residual ridges when the dentures are under
heavy occlusal loads.

39. If the distribution of the soft tissues is uneven,
however, the teeth would contact unevenly when they first
touch. This uneven contact tends to stimulate nervous
patient to clench and relax and closing muscles of the jaws,
which may cause soreness under the denture bases and
changes in the residual ridges.
The use of a technique based on “minimal closing
pressure seems” to produce the best result for most
patients.

40. Problems in retruding the mandible to CR
Difficulties in retruding:
a. Biological Problems
b. Psychological Problems
c. Mechanical Problems
a. Biological Problems:
•Lack of muscle coordination
•Lack of synchronization between protruding and the
retruding muscle due to “HABITUAL” centric position
(long period of edentulousness, only anterior teeth present)

41. b. Psychological Problems:
Both patient and dentist play an important role in
recording the centric relation.
More the dentist becomes irritated
More confused the patient
Less likely the patient will respond to the direction provided
by the dentist.

42. c. Mechanical Problems:
Poorly fitting base plates
Unequal pressure due to unequal resiliency of tissue
(varied thickness)

43. Methods for assisting the patient to
retrude the mandible
1. “Let your jaw relax, pull it back, and close slowly and
easily on your back teeth.”
-simplest,
-easiest, and
-often most effective way of effecting a retrusion of the
mandible into centric relation is by verbal instruction to the
patient.
-Instructions must be given in a calm and confident
manner.
-When the patient is responding properly, the dentist
should say so. In this manner, the patient’s awareness of
the desired position is reinforced.

44. 2. “Get the feeling of pushing your upper jaw out and close
your back teeth together.”
-Many patients are not aware of the jaw movements they
can make.
-By getting the feeling of pushing the upper jaw forward,
they automatically pull the lower jaw back. Once they have
achieved this feeling, it is easy for them to repeat the
desired motion.

45. 3. Instruction the patient to protrude and retrude the
mandible repeatedly while the patient holds the fingers
lightly against the Chin.
The movement into the desired position can be felt by the
patient with the patient’s own fingers on the chin. The
dentist can aid by a slight pressure on the point of the chin.

46. 4. Instruct the patient to turn the tongue backward toward
the posterior border of the upper denture

47. 5. Instruct the patient to tap the occlusion rims or back
teeth together repeatedly.
-Tapping the occlusion rims or back teeth together rapidly
and repeatedly is used to help the patient retrude the
mandible, since it is believed that the center of muscle pull
will gradually work the mandible back.
-However, it is difficult to record these positions, and a
patient can easily tap in a slightly protrusive or lateral
position. The results should be checked by other tests.

48. 6. Tilt the patient’s head back while the various exercises
just listed are carried out.
Often tilting the head backward at the neck will place
tension on the infra-mandibular muscles and tend to pull
the mandible to a retruded position.
However, it is extremely difficult to obtain
registrations with the head in this position because of the
awkwardness of insertion and removal of the recording
medium and occlusion rims from the mouth when the head
is so tilted.

49. 7. Palpate the temporal and masseter muscles to relax
them.
The temporal muscle shows reduced function when
the mandible is in a protruded position. For this reason its
contraction can be felt when the mandible is in or near its
retrusive position and the patient is asked to open and
close.
Massage or palpation of the masseter and temporal
muscles will help patients to relax.

50. 8. Swallowing
9. Boos series of stretch exercise
10. Dawson’s bimanual method

51. Methods of recording CR
BOUCHERS
a. Static methods —interocclusal record ±central bearing
devices ±tracing devices
b. Functional methods —chew-in technique
a) Needles technique
b) House technique
c) Essig technique
d) Patterson technique

52. MICHAEL L MEYER (1982) —4 Categories
1. Direct checkbite (interocclusal) record
2. Graphic recording (intraoral & extraoral)
3. Functional recording
4. Cephalometrics
HEARTWELL
1. Functional methods (chew-in)
a) Needles House method
b) Patterson method
c) Meyer’s method
2. Graphic Method
a) Intraoral devices
b) Extraoral devices
3. Physiological or tactile or interocclusal check record
method

53. SHARRY
-Check bite
-Excursive recording
-Terminal hinge axis recording
-Deglutition

54. KAPUR AND YURKSTAS

55. Functional method
•Patterson and Needle House Technique.
•Both based on same principle.
i.e. the patient produces a pattern of mandibular
movements by moving the mandible to protrusion,
retrusion, and right and left lateral.

56. •Needle-HouseMethod
-usescompoundocclusalrimswithfourmetalstyli
placedinthemaxillaryrim.
-whenthemandiblemoveswiththestylicontactingthe
rim,thestylicutfourdiamondshapedtracings.
-thetracingsincorporatethemovementsinthree
planes,andtherecordsareplacedonasuitablearticulator
toduplicatetherecord.

57. •Patterson Method
-uses wax occlusal rims.
-a trench is made in the mandibular rim, and a mixture
of half plaster and half carborudum paste is placed in the
trench.
-when the plaster and carborundum are reduced to the
pre-determined VDO, patients are instructed to retrude the
mandible and occlusion rims joined.

58. Patterson Method

59. •Meyer’s technique:
-used soft wax occlusal rims.
-tinfoil was placed over the wax and lubricated.
-patient performed functional movements to produce a
wax path
-plaster index was made

60. •Shanahan’s technique:
-placed cones of soft wax on the mandibular rim and
had the patient swallow several times
-during swallowing the tongue forced the mandible
into CR

61. •Nick and Notch method :

62. Graphic method
•The first known “needle point tracing” was by Hessein 1897.
•The technique was improved and popularized by Gysi around
1910.
•Phillipsrecognized that any lateral movements of the jaw
would cause interference of the rims which could result in a
distorted record.
•He developed the “ central bearing point ” which supposedly
produced equalisation of pressure.

63. •Later graphic recording methods used the central bearing
point to produce the gothic arch tracing.
•Hardy and Pleasure described the use of the coble balancer,
and Hardy later designed a modified intra-oral tracer similar
to the coble.

64. •Record a tracing of mandibular movements in one plane,
an arrow point tracing.
•It indicates the horizontal relation of the mandible to the
maxillae.
•Do not confuse this with other graphic tracings that are
made in additional planes.
e.g. pantographic tracings, are made in three planes.

65. •Graphic method are either:
a. intra oral
b. extra oral
•Graphic methods can record eccentric relations
•Are the most accurate visual means of making a centric
relation record with mechanical instruments.
( checked with intero-cclusal check record )

67. GRAPHIC METHOD
•Intra-oral v/s extra-oral
•Limitations of graphic method:
a. difficult in excessively resorbed and flabby ridges (
instability of bases)
b. difficult in cases of inadequate inter-arch distance
c. patients with TMJ arthropathy
d. class II & III jaw relations because of the difficulty to
stabilize base and centralize the force.

68. Evaluation of arrow point tracing
(Gerber)
Typical Flat AssymetricalApex absent round
Miniature Double arrow Dorsally extended Atypical form
Interrupted

69. Pantography
A pantograph is used clinically to measure mandibular
movement. There are two types of pantographs.
a. The mechanical type developed by McCollum and
Staurt (1955).
b. The electronic type recently developed.
The mechanical pantograph requires complex
handling procedures in clinical and in laboratories . In
addition, the mechanical pantograph’s weight and size are
cumbersome .

70. Recording materials
(1)waxes
(2)impression compounds,
(3)dental plaster, and
(4)zinc oxide and eugenol paste.
(5) Elastomeric impression material
The waxes are low fusing, offer very little resistance
to jaw closure when soft, and will harden quickly. Waxes
are capable to making a record upon contact, and the
jaws can be separated at once. This is advantageous when
the muscular control of the mandible is poor..

71. The compounds, plaster, and zinc oxide and eugenol
paste must be maintained in contact until they are hard. If
the mandible moves before the material sets, the record is
not acceptable. The setting or hardening time can be
controlled to some extend with plaster, less with zinc oxide
and eugenol paste, and not at all with compounds.
Waxes are easily distorted, and unless extreme care is
exercised when the records are positioned, an error can
occur. Compound, zinc oxide and eugenol paste, and
plaster will break before they will distort. This is
particularly true with plaster.

72. Cephalometrics
•Use of cephalometrics to record CR was described by Pyott
and Schaeffer.
•The proper CR and vertical dimension of occlusion were
determined by cephalometric radiographs.
•This method, however, was somewhat impractical and never
gained widespread usage.

73. Recording CR In Dentulous State
•In the dentate individual the CR recordis taken ata
slightly increased OVDjust priorto tooth contactwith
the mandible rotating about the terminal hinge axis.
•If tooth contact occurs, involuntary programmed
mandibular deviation from the hinge axis will result due to
sensory feedback from periodontal ligament
mechanoreceptors.

74. •Neuromuscular conditioningand the abolition of reflex
patternsof closure can be achieved by:
a. the patient biting the teeth together hard,
b. biting on cotton rolls,
c. holding the mouth open wide,
d. use of an anterior jig
e. use of an occlusal splint.

75. •These methods will result in masticatory muscle fatigue
and relaxation, thus permitting easier operator-
manipulation of the mandible.
•Closing the articulated study casts through the thickness of
the registration permits the identification of RCP and its
relation to ICP. Errors from recording about an arbitrary
hinge axis will result in the erroneous detection of tooth
contacts.

76. •Helkimofound no difference in recordings between supine
and upright patients.
•Pain from the operator's guidance technique, the
temporomandibular joints or from muscle tension will
result in reflex mandibular protrusion and hence erroneous
recordings.
•Psychological tension and anxiety will also increase
muscle tension. The number of teeth, their condition or the
ridge form of edentulous patients will effect the stability
of the recording medium and thus the quality of the
recording.

77. Mandibular guidance & CR
•The aimof mandibular guidance is to help locate the
condylar heads in the glenoid fossae at the terminal hinge
axis in a consistent manner, thus producing mandibular
closure about the terminal hinge axis.
•Mandibular guidance methodscan be divided into
a. patient-guided and
b. operator-guided

78. Patient-guided recording of CR
1. Schuyler technique:
•Patient places tip of the tongue to the back of the palate
and closing into a horseshoe of softened wax with light
pressure.
•Adv: Quick and simple technique
Can also be used for edentulous patient.

79. Patient-guided recording
•Disadv:
-There is no way of verifying the nature of any unwanted
tooth contact or the retrusion of the mandible.
-In addition the wax may not be uniformly softened
which can lead to inaccuracies in the recording.

80. 2. Physiological technique
•This method uses cones of soft wax placed posteriorly.
•The patient swallows several times, simultaneously the
mandible retrudes and the recording is made.
•Besides the uniformity of softness of the wax, there is no
control over the mandibular retrusion nor any tooth
contact.
•More appropriate for the edentulous patient.
Patient-guided recording

81. 3. Gothic arch (Arrow-point) tracing
•in both dentate and edentulous patients.
•used intra-or extra-orally and is based on tracing the
movement of the mandible.
•Drawbacks:
-relatively time consuming
-requires non-displaceable upper and lower alveolar ridges
to allow stable and retentive acrylic bases.
-Large tongues movement of denture
Patient-guided recording

82. •Advances in Gothic arch (Arrow-point) tracing
•Revisited in the Biofunctional Prosthetic System (Ivoclar
Vivadent, Germany) for CD
Gnathometer ‘M’
consists of wax rims with tracing plates.
•Digital pantograph machines
(ARCUS Digma,Kavo, Germany; Denar Cadiax System,
Waterpik Technologies, USA)
adv: much simpler than the traditional set ups. They have
an electronic facebow
Patient-guided recording

83. 4. Myo-monitor:
•is an electrical jaw muscle stimulating device which is
reputed to achieve muscle relaxation and produce a
neuromuscular mandibular position.
•e.g. J-4 Muscle Stimulator
(Myotronics-Noramed Inc, USA)
•produces pulsed ultra-low frequency stimulation of facial
and masticatory muscles.
Patient-guided recording

84. •Stimulating electrodes are placed over the coronoid
notches and a common electrode is located at the nape of
the neck.
•Proponents of the myo-monitor suggest that the ‘jaw-
closer' muscles act simultaneously, via reflex contraction,
to produce a reproducible retruded mandibular position
•Not gained much popularity :
1. Myo monitor CR is anterior to normal CR
2. Myo monitor CR is not reproducible
3. when compared to CR Myo monitor is different on left and
right side of the same pat
Patient-guided recording

85. Operator-guided recording of CR
1. Chin-point guidance method:Guichet ( 1970 )
•Positions the condyle in the RUM position.
•The patient is seated upright and relaxed with the clinician
positioned in front.
•A softened two-layer wax wafer (1.4 mm thick) is gently
pushed against the cusps of the maxillary teeth with just
enough force to make slight cuspal indentations.

86. Operator-guided recording
•Chin-point guidance method:
•The wafer is removed, chilled and re-seated in order to
check fit and stability. A registration medium is applied to
the mandibular surface of the wax wafer and the patient's
mandible is guided into a hinge closure by the thumb and
index finger of the operator.
•The mandible is then manually manoeuvred a few times
about the hinge axis. Afterseveral smooth movements the
hinge closure is completed until the
mandibular teeth just indent the registration
material.
•The risk with this method is the ease with
which the condyles can be over-retruded.

87. 2. Three finger chin-point guidance method:
Peter Thomas (1980)
•A tripod is created at the chin-point and lower border of
the mandible on both sides by the thumb, index and third
finger. Gentle guidance along all three digits is required in
a mid-sagittal plane.
•This encourages anterior-superior placement of the
condyles but care is required as it is easy to deflect the
mandible to one side.
•not recommended for edentulous subjects because the
operator's hand position can lead to displacement of the
lower denture base.
Operator-guided recording

88. 3. Three finger chin-point guidance method:
Operator-guided recording

89. 4. Anterior guidance by a Lucia Jig:
•The basis of the Lucia jig method and thetechniques that
follow, is to provide an anterior reference point. This forms a
tripod with the condyles, helping them to locate in the most
anterior-superior position in the glenoid fossae.
Operator-guided recording

90. 4. Anterior guidance by a Lucia Jig:
•With the teeth out of contact all proprioceptive reception from
the teeth and musculature is removed. An anterior stop also
stabilizes the mandible during recording and permits minimal
tooth separation so that the recording medium is as thin as
possible.
Operator-guided recording

91. •Anterior guidance by a Lucia Jig:
•The Lucia jig is made from self-curing acrylic resin on a study
cast or in the mouth.
•If carried out intra-orally care must be taken because of the
exothermic setting reaction of the acrylic.
•At the dough the acrylic resin is adapted to the upper anterior
teeth, using soft paraffin as a separator. The palatal acrylic is
manipulated to just cover the palatal soft tissues.
Operator-guided recording

92. •The lingual aspect should
slope posteriorly and
superiorly at an angle of
between 40–60°and a
wooden spatula can be
useful in achieving this.
•While the jig sets it must
be gently taken on and off
the teeth to avoid
engaging undercuts and to
reduce the chance of
thermal trauma.
Operator-guided recording

93. •Anterior guidance by a Lucia Jig:
•Once completed the jig is adjusted using articulating paper
placed on the palatal aspect whilst the patient performs lateral
and antero-posterior excursive movements.
•A selected lower incisor scribes an arrow-head pattern, the
‘wings' and ‘tail' of which can be ground away to leave the
apex.
Operator-guided recording

94. •Anterior guidance by a Lucia Jig:
•This process is repeated until a raised area of acrylic at the
apex remains.
•This is the location of the centric position and the vertical
height is then adjusted until the posterior teeth are just out of
contact. The record is made at this position with the jig in the
mouth.
Operator-guided recording

95. •Anterior guidance by a Lucia Jig:
•It is important to note that while the jig is being adjusted out
of the mouth, the patient must bite on a cotton wool roll or a
saliva ejector in order to keep the teeth discluded otherwise
the training effect of the jig will be lost.
•This method can also be used if upper anterior teeth are
missing. The jig is simply made to span the edentulous area
and is adjusted in the same manner.
Operator-guided recording

96. 5. Anterior guidance by a Leaf Gauge:
•Another variation of the Lucia jig principle involves the leaf
gauge. Originally, a book of ten acetate leaves was described
but now disposable paper versions are also available
(Panadent Corp., CA, USA).
•The leaves provide the anterior reference point and the degree
of tooth separation can be altered until the teeth achieve
disclusion.
•No adjustment using gothic arch principles is possible. A
registration support wafer permits the registration of the inter-
dental record
Operator-guided recording

97. •Anterior guidance by a Leaf Gauge:
Operator-guided recording

98. 6. Anterior guidance by a tongue blade:
•The tongue blade method uses wooden spatulas instead of a
custom made Lucia jig to provide an anterior reference point.
•The degree of tooth separation can be altered by the number
of spatulas used.
•The patient's teeth must be discluded for a period of time,
usually between 10–20 minutes prior to registration, in order
for proprioceptive input to be lost.
Operator-guided recording

99. Anterior guidance by a tongue blade:
•No adjustment using gothic
arch principles is possible
and once the correct anterior
spatula guidance is
achieved, registration
material is used to record
the relative position of the
mandibular and maxillary
teeth.
Operator-guided recording

100. 7. Anterior guidance by a OSU Woelfel Gauge:
•This method was developed by Woelfel at Ohio State
University (OSU) and aims to simplify the Lucia jig technique
while still achieving an anterior point contact at the centric
position.
•The specially designed device (Girrbach Dental GmbH,
Germany) has a graduated acetate bite platform, the position
of which is adjusted antero-posteriorly until the teeth are
minimally out of contact. A registration support wafer can
then be added and the inter-dental record made.
Operator-guided recording

101. •Anterior guidance by a OSU Woelfel Gauge:
Operator-guided recording

102. Conclusion
The accurate determination, recording, and transfer of
jaw relation records from the edentulous patient to the
articulator is essential for the restoration of function, facial
appearance, and the maintenance of the patient’s health.
Unsatisfactory maxillo Mandibular relationships will
eventually lead to failure of complete dentures and
necessitate time-consuming and costly remakes.

103. There is probably no best method for recording centric
relation. A method proven to be good for one dentist might
fail for another.
Both accurate and incorrect records of centric relation
have been made by these methods. This means that,
irrespective of the method used, subsequent clinical
checking and rechecking must be done throughout the
denture construction phases.
Conclusion