Transcript Biological considerations of orientation, vertical and

Biological considerations of
orientation, vertical and
horizontal jaw relations in
complete denture- Second part
Short Learning Objectives
1. Definition of Horizontal relation
2. Importance and Significance
3. Method of recording
Centric relation
• GPT 4,
The horizontal jaw relation when the condyles are in the most posterior,
unstrained position in the glenoid fossa at any given degree of jaw
separation from which the lateral movements can be made.
• BOUCHER
The most posterior relation of the lower to the upper jaw from which
lateral movements can be made at a given vertical dimension .
GPT- 8 definition
The maxillomandibular 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.
Importance of centric relation
• Centric relation is a reproducible and stable and
comfortable position.Therefore it is used as a
reference when mounting dentulous and
edentulous casts in articulator.Thus CR serves
as a reference relationship for establishing an
occlusion.
• When CR and CO of artificial teeth do not
coincide the stability of denture bases is in
jeopardy and patient will have unnecessary pain
or discomfort.
3 primary requirements:
1. To record the correct horizontal
relationship of mandible to maxilla
2. To expert equalized vertical pressure
3. To retain record in undistorted condition
until the cast have been accurately
mounted on articulator
SIGNIFICANCE
 In case of dentulous patients
proprioceptive impulses are obtained from
PDL.
 In case of edentulous patients centric
relation act as proprioceptive centre to
guide occlusal movements.
SALIENT FEATURES: 6 R
1- Retruded
2. Repeatable
3. Recordable
4. Reproducible
5. Point of return
6. Point of reference.
Effective manipulation of mandible requires delicacy and firmness.
METHODS FOR ASSISTING THE PATIENT TO RETRUDE THE
MANDIBLE.
 Relaxing the jaw and closing
 Repeatedly protruding and retruding the mandible
 Swallowing and closing
 Tapping the rims or back teeth repeatedly
 Touching the tip of the tongue to the posterior aspect of the palate or
denture border and bite.
 Palpate the temporal and massater muscles to relax them.
METHODS TO RECORD CENTRIC
RELATION:
 Physiological or tactile or inter occlusal check
record method
 FUNCTIONAL
• Needle house method
• Patterson method
 GRAPHIC
• Intra oral
• Extra oral
Physiologic method
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Based on:
Proprioceptive impulse of patient
Kinethetic sense of mandibular movement
Visual acuity and sense of touch of patient
Technique is divided into two steps in edentulous condition• Tentative records using occlusion rims attached to accurate
stable record bases.
• Inter occlusal check records with the teeth arranged for try
in.
INDICATIONS
 Abnormally related jaws.
 Displaceable flabby tissue.
 Large tongue
 Uncontrolled mandibular movements.
 In patients already using a complete denture
• Material used
1. Waxes: low fusing
2. Impression compound
3. Dental plaster
4. ZnOE paste
PROCEDURE
a) Recording tentative jaw relation:
• Maxillary occlusal rim inserted to patients
mouth.
• Vertical dimension at rest is established.
• Mandibular occlusal rim inserted and
reduced accordingly,
• Using base plate wax, make a tentative CR
record by having the patient retrude close
the jaws until he feels the closure to be at
tentative vertical dimension of jaw
separation.
b) Making the inter occlusal check record.
• Upper and lower trial dentures are inserted into the
mouth. Do not let the patient make tooth contact. If
premature tooth contact exists with the jaws in centric
relation, the patient’s proprioception may not direct
the return to this identical position.
• Aluwax is added on the occlusal surface of teeth of
mandibular occlusal rim
• Patient asked to retrude mandible and close on the
wax till tooth contact occurs.
• Trial dentures removed and allowed to cool.
Functional method
• Method utilize the functional movements of jaws to record the
centric relation.
• Patient asked to perform border movements such as protrusive and
lateral excersion movement.
a)
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Needle house method
Fabrication of occlusal rim made from impression compound
Four metal beads or styli are embedded into premolar and molar
areas of maxillary occlusal rim.
Occlusal rim inserted into patients mouth and asked to close
occlusal rim and make protrussive,retrussive ,right and left
movement of mandible.
When movements are made “diamond shaped marking pattern
rather than a line is formed on the mandibular occlusal rim.
• Patient produces mandibular movements by
moving mandible to protrusion , retrusion,
right and left lateral
b)Patterson method
• Occlusal rim made of modelling wax.
• In trench or trough is made along the length of
mandibular occlusal rim.
• A mixture of carborundum and dental plaster is
loaded into the trench.
• Perform mandibular movement till
predetermined vertical dimension.
• Movement generates compensative curves in
plaster
Graphic method
• The graphic method record a tracing of
mandibular movements in one plane
• 2 types:
1) Arrow point tracing
2) Pantograph
Arrow point tracing is a graphic record measured
across single plane
Pantogaph is measured three dimensionally.
Factors to be considered while
carrying out tracing
1.
2.
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6.
7.
Stability of denture base
Resistance of rims
Difficulty in placing central bearing device
Height of residual alveolar ridge
Tongue interference
Efficiency of recording device
Lack of coordinated movements
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Made using gothic arch tracers
Recorded in horizontal plane.
Consists of central bearing device:a device that provide
central point of bearing or support between the maxillary
& mandibular dental arches.
consists of contacting point attached to one dental arch
and plate attached to opposing dental arch
Plate provide surface on which the tracing of mandibular
movements is recorded.
Consists of: CENTRAL BEARING POINT & CENTRAL
BEARING PLATE.
• TYPES OF ARROW POINT TRACERS:
1) INTRA ORAL TRACING POINT:
• Central bearing device is located intra orally.
• Tracer is placed within the mouth.
• Central bearing point & plate is inserted into patients
mouth.
• Central bearing point is adjusted such that it contact the
central bearing plate at predetermined vertical dimension.
• Ask to make anteroposterior and lateral movements.
• Central bearing point will draw the tracing pattern on
central bearing plate
• Tracing should resemble an arrow point with a sharp apex.
2)EXTRA ORAL POINT TRACER:
• Concept similar to intra oral tracer.
• Additionally have an attachment that project outside
mouth.
• Record bases attached to recording devices inserted in
patients mouth.
• Central bearing point is retracted to conduct training
exercises.
• Recording plate which projects extra orally is coated with
precipitated chalk and denatured alcohol.
• Patient asked to perform all movements.
• Examine for sharp apex.
ECCENTRIC JAW RELATION
• “any relationship of mandible to maxilla other
than centric relation”
• Include protrusive and lateral relations.
• Help to adjust the lateral and horizontal
condylar inclination in the articulator.
• Thus helps the articulator to reproduce
eccentric movements of mandible and
establish balanced occlusion.
• Recorded using functional or tactile method.
Take home message….
• Correct recording of Jaw relation records are
very essential for successful fabrication of
complete denture. Failure to record properly
will ultimately lead to failure of prosthesis.
Multiple Choice Questions
1. Free way space isA. VDR-VDO
B. VDO-VDR
C. VDR- IOD
D. VDO+IOD
2. Face bow helps to recordA. Vertical Jaw Relation
B. Horizontal Jaw Relation
C. Orientation Jaw Relation
D. Centric Relation
3. Which of the following is not the type of Face
bowA. Kinematic
B. Fascia
C. Ear Piece
D. Condyle
4. Average InterocclusaL distance isA. 1-2mm
B. 2-3mm
C. 1-3mm
D. 2-4mm
5. Face bow is helpful when change is expected
inA. Vertical Jaw Relation
B. Horizontal Jaw Relation
C. Orientation Jaw Relation
D. Centric Relation
6. Point taken during recording orientation jaw
relation areA. 3-2 anterior and 1 Posterior
B. 3- 1Anterior and 2 Posterior
C. 4-2 anterior and 2 Posterior
D. 2- 1Anterior and 1 Posterior
7. Graphic method is used to recorda. Vertical jaw relation
b. Horizontal jaw relation
c. Orientation jaw relation
d. Physiological jaw relation
8. According to newer definition, centric relation
isa. RUM
b. MS
c. AS
d. SUM
9. Patterson method, which is used to record
centric relation, isa. Physiological method
b. Functional method
c. Graphic method
d. Radiological method
10. Which of the following is not the feature of
centric relationa. Retruded
b. Repeatable
c. Recordable
d. rechargeable