This document discusses different methods for recording jaw relations when fabricating cast partial dentures. It describes 5 main methods: 1) Direct apposition of casts, 2) Interocclusal records with posterior teeth remaining, 3) Occlusal relations using occlusal rims, 4) Jaw relation records made directly on occlusal rims, and 5) Establishing occlusion by recording occlusal pathways. It also discusses the importance of recording the orientation, vertical, and horizontal jaw relations, including the significance of centric relation.

1. Department of
prosthodontics
TOPIC- JAW RELATIONS IN CAST
PARTIAL DENTURE
PRESENTOR- Diya Sharma
ROLL NO-54
III BDS
GUIDED BY- Dr. Sonal Pamecha

2. INTRODUCTION
• JAW RELATION- Any relationship of
mandible to maxilla-GPT.
• Maxillo-mandibular relationship is defined
as any spatial relationship of maxillae to the
mandible; any of the infinite relationships of
mandible to maxilla.
Why we record jaw relation?
1-To establish and maintain a
harmonious relationship with all oral
structures and to provide a masticatory
apparatus that is efficent and
esthetically acceptable.
2- To ensure that all the effects of
occlusal loading be distributed as evenly
as possible to all supporting structures
capable of receiving the force.

3. 3-To best control the undesirable effects of
rotational or torquing forces onthe
prosthesis.
4- To prevent any deflective contacts of the
teeth during centric or eccentric closures as
these can produce pathological changes in
the supportive structures or in the
neuromuscular mechanism that controls
mandibular movement.
EVALUATION OF DIAGOSTIC
CAST:
• Provide information which is difficult to
obtain by intraoral examination:-
• 1-inter arch distance, enlarged maxillary
tuberosity, undercuts.
• 2-occlusal plane.
• 3-tipped or mal posed teeth.
• 4-occlusion, lingual surfaces can be
assessed , selective grinding and coronal
reshaping , interferences.

4. METHODS OF RECORDING
JAW RELATIONS IN CAST
PARTIAL DENTURE
1. DIRECT APPOSITION OF CAST -
The first method is used when sufficient
opposing teeth remain in contact to make the
existing jaw relationship obvious, or when only
a few teeth are to be replaced on short denture
bases and no evidence of occlusal abnormalities
is found.
With this method, opposing casts may be
occluded by hand the occluded casts should be
held in apposition with rigid supports attached
with sticky wax to the bases of the casts until
they are securely mounted in the articulator.

5. 2. INTEROCCLUSAL RECORDS
WITH POSTERIOR TEETH
REMAINING –
• A second method, which is a modification
of the first, is used when sufficient
natural teeth remain to support the
removable partial denture (Kennedy
Class III or IV) but the relation of
opposing natural teeth does not permit
the occluding of casts by hand. In such
situations, jaw relations must be
established as for fixed restorations with
some type of interocclusal record like
using metallic oxide paste, interocclusal
wax record,etc.

6. • The least accurate of these methods is the
interocclusal wax record . The bulk,
consistency, and accuracy of the wax will
influence the successful chilling.
• Excess wax that contacts the mucosal
surfaces may distort soft tissue, thereby
preventing accurate seating of the wax
record onto the stone casts. Distortion of
wax during or after removal from the
mouth may also interfere with accurate
seating.

7. 3. Occlusal relations using occlusal rims o
record base –
1-one or more distal extension areas are
present.
2- a tooth supported edentulous space is
large.
3-when opposing teeth do not meet.
• A third method is used when one or more distal extension
areas are present, when a tooth-supported edentulous
space is large, or when opposing teeth do not meet.
• In any of these situations, jaw relation records are made
entirely on occlusal rims.
• The occlusion rims must be supported by accurate jaw
relation record bases.

8. 4. JAW RELATION RECORD MSDE
DIRECTLY ON OCCLUSAL RIM-
• Indications:-
 When an opposing maxillary complete
denture is to be made concurrently
with a mandibular removable partial
denture.
 Used in those rare situation in which
the few remaining teeth do not occlude
and will not influence eccentric jaw
movements.
 When either arch has only anterior
teeth present. In any of these
situations, jaw relation records are
made entirely on occlusion rims. The
occlusion rims must be supported by
accurate jaw relation record bases.
Here, the choice of method for
recording jaw relations is much the
same as that for complete dentures.

9. • Either some direct inter- occlusal
method or a stylus tracing may be used.
As with complete denture fabrication, the
use of a face bow, the choice of
articulator, the choice of method for
recording jaw relations, and the use of
eccentric positional records are optional,
based on the training, ability, and desires
of the individual dentist.

10. 5. ESTABLISHING OCCLUSION BY
RECORDING OF OCCLUSAL
PATHWAYS-
• The fifth method of establishing
occlusion on the removable partial
denture is the registration of occlusal
path- ways and the use of an
occluding template rather than a cast
of the opposing arch.
• When a static jaw relation record is
used, with or without eccentric
articulatory movements, the
prosthetically supplied teeth are
arranged to occlude according to a
specific concept of occlusion.
• On the other hand, when a functional
occlusal record is used, the teeth are
modified to accept every recorded
eccentric jaw movement.

11. Advantages of functionally
generated pathways.
1- Harmonious occlusion.
2- No recording of complex
mandibular movement required.
3- Recovery of lost vertical
dimension of occlusion.
4- Errors in occlusion are
minimized.
5- Eliminate the need of complex
articulator (simple hinge articulator
is enough).

12. TYPES OF JAW RELATION
i. Orientation relation.
ii. Vertical relation.
iii. Horizontal relation.
a) Centric relation.
b) Eccentric relation.
1. Protrusive records.
2. Lateral records.

13. I. ORIENTATION RELATION
• Are those that orient the mandible to the
cranium in such a way, that, when
mandible is kept in its most posterior
position, the mandible can rotate in
sagittal plane around an imaginary
transverse axis passing through or near
the condyles.
• This axis can be located by means of a
Kinematic Facebow or hinge bow, or it
can be approximated by the use of an
arbitrary type of facebow.
• Transverse hinge axis • An imaginary line
around which the mandible may rotate
within the sagittal plane.
• Sagittal plane • Any vertical plane or
section parallel to the median plane of
the body, that divides a body into right
and left portions.

14. • Terminal Hinge position also called the
Retruded contact position, it is that
guided occlusal relationship, occurring at
the most retruded position of the
condyles in joint cavities.
• Maximum range of terminal hinge
rotation- about 12˚. Inter incisal opening:
18-25 mm
• Facebow - A caliper like instrument used
to record the spatial relationship of the
maxillary arch to some anatomic
reference points, and then transfer this
relationship to an articulator. It orients
the dental cast in same relationship to the
opening axis of articulator.
• Customarily the anatomic references are
the mandibular condyles transverse
horizontal axis and one other selected
anterior point. Also called Hinge bow,
Earbow, Kinematic facebow.

15. Parts of facebow
U SHAPED
FRAME

25. II. Vertical Relation
 The length of the face as determined by the
amount of separation of the jaws-GPT.
 Vertical jaw relation can be recorded in 2
positions:
 Vertical dimension at rest position.
 Vertical dimension at occlusion.

26. AT REST:
▫ also called physiological rest position is
determined when the patient is in an upright
position and is completely at rest.
▫ The mandibular position is produced by a
muscular balance between the muscles of
mastication ,the postcervical muscle group &
suprahyoid muscle group.
▫ At this position, maxillary & mandibular teeth
should not be touching.
▫ The space between maxillary & mandibular
teeth is referred to as the interocclusal rest
space.
At occlusion-
o Determined by measuring the vertical
dimension while the patients teeth are in
maximal intercuspal position.
o The physiological rest dimension will always be
greater than the occlusal vertical dimension.

27. III. HORIZONTAL RELATION
• It is the relationship of mandible to
maxilla in horizontal plane.
• CENTRIC RELATION:
▫ The maxillo-mandibular relationship in
which condyles articulate with the thinnest
avascular portion of their respective disc
with the complex in the anterior superior
position against the slopes of articular
eminences. This position is independent of
tooth contact. This position is discernible
when the mandible is directed superiorly
and anteriorly. It is restricted to a purely
rotary movement about the transverse
horizontal axis.

28. Methods of recording centric
jaw relation.
• Physiological methods-
1. Tactile/inter occlusal check
record method.
2. Pressure less method.
3. Pressure method.
• Functional method-
1. Needle house method.
2. Patternson method.
• Graphic methods-
1. Intraoral
2. Extraoral
• Radiographic method.

29. Significance of centric
relation
1.It is a reproducible and recordable
position, which can be repeatedly
arrived at and thus serves as a reliable
guide to develop centric occlusion in
complete dentures.
2. Centric relation become starting
point to plan and execute the occlusion.
3. Centric relation is related to terminal
hinge axis. In centric relation, condyles
exhibit pure rotation without any
translation.
4. This position is more definite than
the vertical relation and is independent
of the presence or absence of teeth.
5. The final act of masticatory stroke
ends in centric relation.
6. It is a border position and the
posterior limit of the envelope of
motion.

30. METHODS OF ASSISTING THE
PATIENT TO MOVE THE MANDIBLE
TO THE CENTRIC RELATION
1. The patient is instructed to let his
or her jaw relax, pull it back and
close slowly on the back teeth.
2. The patient is instructed to get the
feeling of pushing his upper jaw out
and then close the mouth with back
teeth in contact.
3. Assist the patient to protrude and
retrude the mandible repeatedly with
the operator holding the finger
lightly against the chin.

31. 4. The patient can be instructed to turn the
tongue towards the posterior border of the
upper denture base and close the rims
together until they meet. The disadvantage
with this method is the likelihood of
displacing the mandibular record base by
the action of the tongue.
5. The patient is told to swallow and
conclude the act with the occlusal rims in
contact. However, the person can swallow
when the mandible is not completely
retruded. This method must be verified by
other techniques.

32. DIFFICULTIES IN GUIDING
MANDIBLE TO CENTRIC RELATION
POSITION
• Biologic: It may arise due to lack of
coordination of opposing muscles. When
the patient is requested to close the jaws
in the retruded position, the lack of
synchronization between the protruding
and retruding muscles may be caused by
habitual eccentric jaw positions adopted
by patients to accommodate to
malocclusion..
• Psychological: The more the operator
becomes irritated over the apparent lack
of ability of the patient to retrude the
mandible.Then dentist must be prepared
to calmly spend adequate time in
securing the centric relation records.

33. • Mechanical: It is essential that the
denture bases on which the occlusal rims
is made fit perfectly and do not interfere
with each other. Failure of adaptation of
denture base to the tissue surface may
result in unevenly distributed pressure on
the underlying resilient tissue leading to
discrepancy in jaw relation recording.

34. • ECCENTRIC JAW RELATION-
• Any relationship of mandible to
maxilla other than the centric
relation-GPT.
• It includes protrusive & lateral
relations.
• The main reason in making an
eccentric jaw relation record is to
adjust the horizontal & lateral
condylar incliations in the
articulator.
• They are recorded using
functional/tactile methods.

35. REFERENCES
• Textbook of prosthodontics-
Deepak Nallaswamy Veeraiyan-
2nd edition.
• Textbook of prosthodontics- V
Rangarajan- 2nd edition.