Jaw movements and articulators

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Jaw Movements Articulators
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Jaw Movements
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Opening
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Opening
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Opening
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Opening
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Posselts Figure
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Posselts Investigations
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Posselts Investigations
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Posselts Figure
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Posselts Figure
MP
ICP
RCP
HA
MP Maximal protrusion ICP Intercuspal
position RCP Retruded Contact position HA
Hinge axis MO Maximum opening
MO
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Posselts Figure top edge
MP
ICP
IG
RCP
EE
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Articulators
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Definitions

• Articulators
• A mechanical representation of the jaws and
  temporo-mandibular joints

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Use of articulators

• Diagnosis
• slides and occlusal relationships
• Treatment planning
• Diagnostic wax - up
• Occlusal adjustment
• Fabrication of Splint / Prostheses

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Articulators

• Types
• Simple Hinge
• Average Value
• Semi-adjustable
• Fully adjustable

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Articulators
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Cast Holder
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Cast Holder
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Average Value
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Articulators
BONWILL 1854
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4
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Articulators

• Average Value

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Articulators

• Average Value

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Articulators
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Denar II - Arcon
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Dentatus

• Non Arcon

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Denar II

• Adjustable Condylar Angle, ISS PSS

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Articulators

• Semi-adjustable
• Can alter
• TMJ to Incisor distance
• Bennett Angle
• Condylor Guidance Angle
• Incisal guidance plate

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Articulators

• Needs Facebow recording
• Ideally should be used for complete denture cases

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Facebow recording
For semi adjustable articulator
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Fully adustable Denar 5

• Posterior wall
• Superior wall
• Medial wall
• Inclination of superior wall
• Condylar angle
• Intercondylar ( glenoid fossa) distance
• ISS

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Denar 5a
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Pantographic recording
For fully adjustable articulator
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lots
Difficulty of use
none
Av Value
Fully Adjustable
Hand Held
S-A
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lots
Amount of adjustment
none
Av Value
Fully Adjustable
Hand Held
S-A
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lots
Cost
none
Av Value
Fully Adjustable
Hand Held
S-A
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Articulator use vs time vs cost
lots
lots
Amount of adjustment
Difficulty of use
Cost
none
none
Av Value
Fully Adjustable
Hand Held
S-A
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What if patient doesnt match articulator?
Articulator
Patient
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Articulators
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Articulators
Therefore the distance from the condyle to the
teeth is crucial
We obtain a measurement of this distance with a
facebow
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Facebow
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Interocclusal record

• Used to locate the lower model to the upper
• If lots of good stable occlusal contacts then no
  IOR needed
• If need an RCP record, then we need an IOR that
  is thick and strong enough to obtain a record
  with the teeth separated and in terminal hinge
  axis e.g. Moyco Extra Hard Beauty wax
• For routine ICP records when carrying out
  multiple crowns / bridgework, Blu-mousse just
  over the tooth preps is usually sufficient

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Aids to obtaining THA

• Bimanual manipulation
• Cotton wool rolls
• Anterior jig
• Splint therapy
• Chin-point guidance

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Anterior jig

• Cold-cure acrylic (Duralay/Trim)
• Greenstick

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Anterior jig (trimmed)

• Provides inclined plane

Separation of posterior teeth Allows the use of
easy flowing occlusal recording media such as
Blu-Mousse
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Anterior Jig
From Howatt, Capp Barrett
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Clinically useful settings for articulator

• Condylar angle 25
• Immediate side shift 0.3mm
• Progressive side shift 6

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Incisal guidance table

• Allows shape of palatal to be reproduced
• Allows length of incisors to be maintained

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Tooth to be prepped
Shape created is the inverse of Posselts figure
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Following tooth prep
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Tooth form reconstructed
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Summary

• The choice of articulator depends upon such
  factors as
• Intended use - Skill of the technician
• Availability of equipment - Expense
• Patient's occlusion - Skill of the operator
• The more closely the articulator matches the
  patients anatomy, usually the better the outcome
  and the less adjustment is required at chairside
  on fitting prostheses.

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Thank You