Horizontal jaw relations /certified fixed orthodontic courses by Indian dental academy

HORIZONTAL JAW RELATION

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com




Once

determined

the
and

correct

vertical

allowance

for

dimension
the

is

necessary

interocclusal distance or freeway space has been
made, the jaw relation in the horizontal plane must
be established.


CENTRIC RELATION
Definition: CENTRIC RELATION:
The most retruded position of the mandible to the
maxilla when the condyles are in the most posterior,
unstrained position in the glenoid fossae at an
established vertical dimension.
GPT


FEATURES AND SIGNIFICANCE

 It is ideal arch to arch relationship and hence
optimum position of jaws for the health, comfort
and function of the TMJ.
 It is a mandibular position where the condyle disc
assembly is seated braced in anterior-superior
position against the posterior slope of the
articulator eminence. Although it was believed to
be the rearmost uppermost and midmost in the
glenoid fossa. (RUM POSITION)

 Centric relation is related to terminal hinge axis.
 In centric relation condyles exhibit pure rotation
without any translation.
 It is a reproducible position which can repeatedly
arrived at and thus serves as a reliable guide to
develop centric occlusion in artificial dentures.
 It is a starting point for the arrangement of artificial
teeth to develop maximum intercupsation in complete
denture.

 It is also serves as a reference position for the
institution of occlusal rehabilitation in dentulous
conditions.
 The terminal act of masticatory stroke terminates
in centric relation. It is also a position where
upper and lower teeth are traced against each
other during deglutition.
 Centric relation is a reproducible and stable
position. Therefore it is used as a reference when
mounting dentulous and edentulous casts onto
articulator.

Recordable

5R

Reproducible
Retruded
Reference
Relation

METHODS OF RECORDING CENTRIC
RELATION
I.

FUNCTIONAL CHEW – IN METHODS
I.

Needle – house technique

II. Patterson's method
I.

GRAPHIC METHODS

I.

INTEROCCLUSAL CHECK RECORD METHOD


FUNCTIONAL CHEW-IN METHODS
 In tooth,
pattern
moving
retrusion

the methods patient produces a
of mandibular movements by
the
mandible
to
protrusion,
and right and get lateral.


NEEDLE – HOUSE METHOD
 They used compound occlusion rims with four
metal styli placed in the maxillary rim.
 When the mandible moves with the styli
contacting the mandibular rim, the styli cut four
diamond shaped tracings.
 The tracings incorporate the movements n three
planes and the records are placed on a suitable
articulator to receive and duplicate the record.

PATTERNSON’S METHOD

 The Patterson method uses wax occlusion rims.
 A trench is made in the mandibular rim and a mixture
of half plaster and half carborundum paste is placed
in the trench.
 Mandibular
movements
generate
compensating
curves in the plaster and carborundum.
 When the plaster and carborundum are reduced to
the predetermined vertical dimension of occlusion,
patient s instructed to retrude the mandible and the
occlusion rims www.indiandentalacademy.com
are joined together with metal

GRAPHIC METHOD
 The most common form of exclusive recording is
the Gothic arch tracing.
 It indicated the horizontal relation of the mandible
to the maxillae.
Extraoral
 Gothic arch tracing
Intraoral
 Basic purpose of training is to record the protrusive
and lateral records.

EXTRA ORAL TRACING
 The extra oral tracer consist of
equalization of pressure on the bases.

an

intraoral

 A needle like point called as styli makes the tracing
on the tracing table coated with cartoon suit or wax.
 These tracing are shaped like gothic arch, so they
are referred to as gothic arch tracings.
 They are also known as arrow print tracing.
 The tracing is not acceptable unless a printed apex is
develop.

 A blunted apex usually indicates an acquired
functional relationship.
 Sharp apex indicates position of centric relation.
 Double tracings indicate lack of co-ordinated
movements at a different vertical dimension.


INTRA ORAL TRACING
 The central bearing plate and point is connected
to the proper vertical relation and when the rims
are in place.
 The patient is instructed to perform lateral and
protrusive movements.
 Gothic arch is traced on the plate.


INTEROCCLUSAL CHECK RECORD
METHOD
 Advocated by Trapazqo and Hickey
 The normal functioning of the patients proprioception
and visual acuity and some touch of dentist, useful in
obtaining accurate record.
 The record is made by making a nick and notch on
the maxillary occlusal rim.
 Trough on the mandibular occlusal rim in the region
of 2 nd premolar and 1 st molar area.
 Nick should be placed in the second premolar are
and notch on the 1 st maxillary molar area.



Extra amount of wax is softened and placed
in the trough of lower rim.



Place the rims in the patients mouth.


 Patient is made to retrude the mandible by applying
any one of the methods
a) Instruct the patient to protrude and retrude the
mandible repeatedly while the patient olds the
finger lightly against the chin.
b) Ask the patient to take the tongue backward to
touch the posterior vibrating line and swallow and
occlude.

c.) Ask the patient to swallow repeatedly.
d.) Guide the mandible to centric by holding with
the index, middle finger and thumb on the
chin.
•

Once the wax gets hardened remove the
occlusal rim out.


Thank you
Leader in continuing dental education


Horizontal jaw relations /certified fixed orthodontic courses by Indian dental academy

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Horizontal jaw relations /certified fixed orthodontic courses by Indian dental academy