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The Basic Outline

Mandibular Movements

Mandible is capable of many different,subtle kinds of movements

When a mandible moves, the condylesalso move with itbut with a twist!

Type & direction of condylar movement

will not nessarily be the same in each TMJ

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Three Basic Mandibular Movements

Hinge Movements

Translatory Movements

Lateral Movements

However, a typical mandibular movement is asmooth, fluid blend of two or three of thesebasic movements!

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Subdivisions of the Basic Movements

Hinge Movement:

either opening or closing motions of the

mandible around a horizontal axis that iscommon to both condyles

So, what does this movement look like?

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The Basic Outline

Hinge Movement

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Subdivisions of the Basic Movements

Protrusive or Retrusive Movements (alsocalled Translatory or Sliding Movements:

As the mandible moves during Protrusion,

both condyles leave their fossae and moveforward along the articular eminences

When the mandible Retrudes, both condyles

leave the eminences and move back intotheir respective fossae

How does this movement look?

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Translatory Movement

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Translatory + Hinge Movements

TheFull Envelopeof Hinge and TranslatoryMovements as viewed in the midsaggitalreference plane appears as a special

envelope-like figureknown as:

POSSELTS ENVELOPE(after Dr. Ulf Posseltsbook, The Physiology of Occlusion andRehabilitation)

So,What does this envelope look like?

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Posselts Envelope

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Posselts Envelope fig. 6-7

Represents the mandibles range of verticaland also anteroposterior movement

In your picture the teeth are slightly

separated, incisal edge of mand. Incisor is at

the a position

So, what kind of vertical position of themandible is this (if the teeth are slightlyseparated)?

Yes! This is Physiological Rest Position!

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The Basic Outline

Lets study Fig. 6-7

We need to understand figure

6-7 of Posselts Envelope a

little bit better

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Posselts Envelope fig. 6-7

Predicatable Positions of the Mandible:

#1: Centric Relation

#2: CO or MIP (Centric Occlusion or Max.Intercuspal Position)

#3: Edge to Edge incisor contact

#4: Neg. Horiz. & Vert. Overlaps at incisors

#5: Max. mand. Protrusion

(for #1-#5, teeth are in contact!)

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Posselts Envelope fig. 6-7

Predicatable Positions of the MandibleContinued (note teeth are not in contact!):

a: Physiologic Rest Position

b: Maximum Opening of Mandible (Yawn)

Path 2ab: Path of HABITUAL OPENING/CLOSING

(Physiologic Rest a is along this path too!)Path 1cb: Most RETRUDED Path mandible is

capable of taking

From 1 to C: Condyles in CR & mand. Is makingpure hingemovement (1 or so)

Between c & b: Mandible continues to open, but is

also TRANSLATED FORWARD-condyles out offossae and onto the eminences

Path 5b Most PROTRUDED path mandible is

capable of makingSo, We have Learned about

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What have we learned?

So far we have covered 2 of the 3 MandibularMovements:

Hinge and Translatory Movements

What is the third movement that we stillneed to learn about?

Lateral Movements(Right and Left)

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Lateral Movements(Right and Left Direction)

The side to which the mandible is movingis called the WORKING SIDE

The side that is opposite the WORKING

SIDE is called the BALANCING SIDE The condyle on the WORKING side is

called the.WORKING CONDYLE(akaROTATING CONDYLE)

By exclusion, the other condyle is theBALANCING CONDYLE(akaORBITTING CONDYLE)

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That is all for now!

Exam Next Week! Read up through Page 114(end your reading at the sentence just beforeFigure 6-8) in Chapter #6 AFP Vol. III, BlueBook, Start reading on Page 108.

To summarize, Read from Pg. 108 to 114

Possible Exam Topics will follow

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Exam Topics (17)

Various definitions of

occlusion

The five classical positionsof the mandible

Centric Occlusion/MIP/CO

Occlusal Plane Curves of Spee and Wilson

Overjet/Overbite/

Vertical Overlap/HorizontalOverlap

Angles Classifications I-III

Cusp Types-stamp & shear

Two types of stamp cusparrangements or patterns ofocclusion:

1. CUSP-TO-OCCLUSALEMBRASURE

2. CUSP-TO-FOSSA

Application of the Cusp/FossaPhilosophy

Vertical Dimension/VDO/

Physiologic Rest

Estimating VDO based onspeech sounds

Errors in VDO

(open & closed)

Centric Relation (CR)

Mandibular Movements

(all 3 of them)

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Thank you

Break Time (20 minutes)