mandibular movements f

8/3/2019 Mandibular Movements f

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MANDIBULAR MOVEMENTSMANDIBULAR MOVEMENTS

AndAndJAW RELATIONSHIPSJAW RELATIONSHIPS


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Factors affectingFactors affecting

mandibular movementmandibular movement


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Temporomandibular joint (TMJ)Temporomandibular joint (TMJ)--11

The disc divides the joint into two compartments; upperThe disc divides the joint into two compartments; upperand lower. The lower compartment between the condyleand lower. The lower compartment between the condyle

head and the disc and the upper compartment between thehead and the disc and the upper compartment between the

disc and the Glenoid fossa.disc and the Glenoid fossa.


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Rotation and translationRotation and translation

Rotation occurs in lower compartment of the TMJ.Rotation occurs in lower compartment of the TMJ.Translation occurs in upper compartmeTranslation occurs in upper compartme33nt of the TMJ.nt of the TMJ.

All mandibular movements are combination of rotationAll mandibular movements are combination of rotation

and translation except posterior (when the condyles inand translation except posterior (when the condyles in

most retruded position) opening and closing for aboutmost retruded position) opening and closing for about2020 mm. In this position the condyle do pure rotation.mm. In this position the condyle do pure rotation.


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Contact of opposing teethContact of opposing teeth--22

An example for the effect of the toothAn example for the effect of the tooth

contact on mandibular movement is thecontact on mandibular movement is the

incisal path.incisal path.

is the path taken byis the path taken byThe incisal pathThe incisal path

the incisal edges of the lower incisorsthe incisal edges of the lower incisors

on the palatal surface of the upperon the palatal surface of the upper

incisors until the teeth touch edge toincisors until the teeth touch edge to

edge.edge.

is the angleis the angleThe incisal path angleThe incisal path angle

between the incisal path and thebetween the incisal path and the

horizontal plane.horizontal plane.


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The muscles ofThe muscles of--33

masticationmastication


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andandmassetermasseterThe temporalis,The temporalis,

pterygoidspterygoidsmedialmedialThe temporalis,The temporalis, massetermasseter and medialand medial pterygoidspterygoids areare

elevators.elevators.

Contraction of deep fibers ofContraction of deep fibers of massetermasseter muscle producesmuscle produces

a backwards pull on the mandible, aided by the distala backwards pull on the mandible, aided by the distal

fibers of temporalisfibers of temporalis


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The lateral pterygoid muscleThe lateral pterygoid muscle

Some lateral pterygoidSome lateral pterygoid

fibers are inserted into thefibers are inserted into the

anterior part of the meniscusanterior part of the meniscus

through the capsule pullingthrough the capsule pullingthe condyles forward andthe condyles forward and

downward (protrusion if thedownward (protrusion if the

muscles in the two sidesmuscles in the two sides

act). Action of the lateralact). Action of the lateralpterygoid muscle in one sidepterygoid muscle in one side

pulls the mandible to thepulls the mandible to the

other side.other side.


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They provideThey provideThe TMJ ligaments:.The TMJ ligaments:.--44

limits or borders of the mandibularlimits or borders of the mandibular

movements.movements.

Movements on the boundaries of theMovements on the boundaries of theborderbordermovement space are calledmovement space are called

. Movements within the. Movements within themovementsmovements

boundaries of movement space can beboundaries of movement space can be

..border movementsborder movements--intraintradesignated asdesignated as

55-- The neuromuscular regulation of theThe neuromuscular regulation of the

above factors.above factors.


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Basic mandibularBasic mandibular

movementsmovements


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Opening and closingOpening and closing

starts fromstarts fromHabitual openingHabitual opening

the intercuspal position to thethe intercuspal position to the

maximum opening position.maximum opening position.

The closing movement is inThe closing movement is in

reverse; from maximumreverse; from maximum

opening to intercuspalopening to intercuspal

position. Translation (forwardposition. Translation (forwardand downward) and rotationand downward) and rotation

of the condyle occur duringof the condyle occur during

this movement.this movement.


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orward (protrusive) movementForward (protrusive) movement--22

The condyle moves with the disk forward andThe condyle moves with the disk forward and

downward. The path of the condyle during thisdownward. The path of the condyle during this

horizontal (sagittal)horizontal (sagittal)movement is termed themovement is termed the

..condylar pathcondylar path

horizontalhorizontalIt make an angle with horizontal calledIt make an angle with horizontal called

condylar path angle.condylar path angle.

1= horizontal condylar path

2= horizontal plane.

3= horizontal condylar path

angle.


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s phenomenons phenomenonChristensenChristensen

During protrusion separation of posterior teethDuring protrusion separation of posterior teeth

occurs due to the downward and forwardoccurs due to the downward and forward

movement of the condyle . This calledmovement of the condyle . This called

..Christensens phenomenaChristensens phenomena


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))retrusiveretrusiveBackward (Backward (--33

movementmovement

TheThe retrusiveretrusive movementmovement ofof thethemandiblemandible isis similarsimilar toto thethe protrusiveprotrusive

oneone butbut inin aa reversereverse


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Lateral movementLateral movement--44

The side to which theThe side to which themandible moves is calledmandible moves is called

TheTheworking side.working side.

condyle do rotation withcondyle do rotation withslight translationslight translation

movement).movement).(Bennett(Bennett

The other side is calledThe other side is called

non working ornon working or

; the condyle; the condylebalancingbalancing

moves downwardmoves downward

forward and medially.forward and medially.


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Lateral movement of the mandible.Lateral movement of the mandible.11, the lateral condylar path angle, the lateral condylar path angle

in the balancing side (Bennettin the balancing side (Bennett

angle).angle). 22, is the Bennett movement, is the Bennett movement

in the working side.in the working side.

The lateral condylarThe lateral condylar

is the path alongis the path alongpathpathwhich the balancingwhich the balancing

condyle head movescondyle head moves

medially during lateralmedially during lateral

movement.movement.

The lateral condylarThe lateral condylar

it is theit is thepath anglepath angle

angle between theangle between the

lateral condylar pathlateral condylar path

and the sagittal planeand the sagittal plane


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Bennett movementBennett movement

Bodily shift ofBodily shift of

the mandiblethe mandible

occurs duringoccurs during

laterallateral

movementmovement

called Bennettcalled Bennett

movement.movement.


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Jaw relationshipsJaw relationships

It is any relation of the mandible toIt is any relation of the mandible to

the maxilla. It is classified intothe maxilla. It is classified into

vertical, horizontal and orientationvertical, horizontal and orientationrelationsrelations


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Vertical relationsVertical relations--IIIt represents the amount of jaw separation andIt represents the amount of jaw separation and

classified into:classified into:

; the vertical; the verticalVertical dimension of occlusionVertical dimension of occlusion--11

measurement of the face when the teeth are inmeasurement of the face when the teeth are in

occlusion.occlusion.; the vertical; the verticalVertical dimension of restVertical dimension of rest--22

measurement of the face when mandible at restmeasurement of the face when mandible at rest

position.position.


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way spaceway space--FreeFree

is obtained when theis obtained when theThe rest positionThe rest position

patients head is upright and the elevator andpatients head is upright and the elevator and

depressor muscles are in equilibrium. At restdepressor muscles are in equilibrium. At rest

the teeth are not in contact, the gap in betweenthe teeth are not in contact, the gap in between

or theor theinterocclusal distanceinterocclusal distanceis called theis called thefreeway spacefreeway space


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Measurement of verticalMeasurement of vertical

dimensiondimensionThe vertical dimension of rest is measured betweenThe vertical dimension of rest is measured between

two points one on patients nose and other on chin.two points one on patients nose and other on chin.

ThenThen 22--44 mm are subtracted to be the verticalmm are subtracted to be the verticaldimension of occlusion.dimension of occlusion.


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Horizontal relations:Horizontal relations:--IIII

TheyThey areare anteroposterioranteroposterior andand sideside--toto--

sideside relationsrelations ofof thethe mandiblemandible toto

maxillamaxilla.. TheyThey includeinclude::


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Centric occlusion:Centric occlusion: ItIt isis thethe relationrelation ofof opposingopposing occlusalocclusal

surfaces,surfaces, whichwhich providesprovides thethe

maximummaximum plannedplanned contactcontact andand /or /orintercuspationintercuspation..


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Centric relation.Centric relation.

It is the relation of the mandible to the maxillaIt is the relation of the mandible to the maxillauppermost anduppermost andwhen the condyles are in thewhen the condyles are in the

position in the glenoid fossa.position in the glenoid fossa.rearmostrearmost

In complete denture construction , it should beIn complete denture construction , it should berecorded and transferred to the articulator forrecorded and transferred to the articulator for

setting up of teeth.setting up of teeth.


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Centric occluding relationCentric occluding relation::

ItIt isis aa termterm sometimesometime usedused toto describedescribethethe conditioncondition inin whichwhich thethe jawsjaws areare inin

centriccentric relationrelation andand thethe teethteeth areare inin

centriccentric occlusionocclusion..


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Eccentric relations:Eccentric relations:

TheyThey areare anyany relationsrelations ofof thethe

mandiblemandible toto thethe maxillamaxilla otherother thanthan

centriccentric.. TheyThey areare thethe protrusive,protrusive,

rightright andand leftleft laterallateral relationsrelations..

Working side Balancing sideProtrusive contact


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--craniocranioOrientation relations (Orientation relations (--IIIIII

))maxillary orientationmaxillary orientation TheThe relationshiprelationship betweenbetween thethe maxillamaxilla andand

thethe condylescondyles oror thethe craniumcranium isis recordedrecorded

byby thethe faceface bowbow andand transferredtransferredunchangedunchanged toto thethe articulatorarticulator..


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BOWBOW--FACEFACE

The faceThe face--bow is a caliperbow is a caliper--like device that is usedlike device that is usedto record the relationship of the maxilla to theto record the relationship of the maxilla to the

temporomandibular joints or the opening axis oftemporomandibular joints or the opening axis of

the jaws and to orient the casts in this samethe jaws and to orient the casts in this same

relationship to the opening axis of the articulatorrelationship to the opening axis of the articulator


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bowbow--Types of faceTypes of face


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bowbow--The kinematic faceThe kinematic face--11

(mandibular, hinge axis locator ):(mandibular, hinge axis locator ):

It is used to locate theIt is used to locate the

kinematic (true or terminal)kinematic (true or terminal)

transverse hinge axis.transverse hinge axis.isisThe transverse hinge axisThe transverse hinge axis

an imaginary line, which thean imaginary line, which the

mandible rotates duringmandible rotates during

posterior (maximum retrusion)posterior (maximum retrusion)

opening and closing for aboutopening and closing for about

2020 mmmm


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bowbow--The maxillary faceThe maxillary face--22It is used to record the position of theIt is used to record the position of the

upper jaw in relation to the hinge axis andupper jaw in relation to the hinge axis and

transferring the relation to an articulatortransferring the relation to an articulator

The maxillary faceThe maxillary face--bow is oriented to thebow is oriented to the

kinematic or arbitrary hinge axis.kinematic or arbitrary hinge axis.


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The arbitrary hinge axisThe arbitrary hinge axisis positioned on a line extending from theis positioned on a line extending from the

outerouter canthuscanthus of the eye to the middle ofof the eye to the middle of

the tragus of the ear and approximatelythe tragus of the ear and approximately

1313 mm. in front of the external auditorymm. in front of the external auditory

meatus.meatus.


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bowsbows--The ear faceThe ear face

are designed to utilize an arbitrary axisare designed to utilize an arbitrary axisby fitting into the external auditoryby fitting into the external auditory

meatus.meatus.


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ReferencesReferences11--AllenAllen AA, Heath JR, Mc Cord:AA, Heath JR, Mc Cord: CompleteComplete ProsthodonticsProsthodontics;; Problems, Diagnosis and Management. MosbyProblems, Diagnosis and Management. Mosby--

Wolf, London,Wolf, London, 19951995..

22-- BeresinBeresin, V.E. and, V.E. and SchiesserSchiesser, F. J.: The neutral zone in complete and partial dentures., F. J.: The neutral zone in complete and partial dentures. 22nd ed. St. Louis, Thend ed. St. Louis, The

C.V. Mosby Company:C.V. Mosby Company: 19781978..

33-- Coleman, R. D. andColeman, R. D. and kaiserkaiser, W. B.: The Scientific Bases of Dentistry. Philadelphia,W. B. Sounders;, W. B.: The Scientific Bases of Dentistry. Philadelphia,W. B. Sounders; 19661966..

44-- CraigCraig, R.G.: Restorative Dental Materials., R.G.: Restorative Dental Materials. 88thth ed. St. Louis, C. V. Mosbyed. St. Louis, C. V. Mosby CompanyCompany..

55--FennFenn, H.R.B.;, H.R.B.; LiddelowLiddelow, K.P. and, K.P. and GemsonGemson, A.B.: Clinical Dental Prosthetics., A.B.: Clinical Dental Prosthetics. 22 ed. London, Staples;ed. London, Staples; 19741974..

66-- GeeringGeering AH,KundertAH,Kundert M ,M , KelesyKelesy C: Complete denture andC: Complete denture and overdentureoverdenture Prosthetics. Theme medicalProsthetics. Theme medical

publication Inc. New York,publication Inc. New York, 19931993..

77--GrantGrant AR, Heath JR, Mc Cord JF: CompleteAR, Heath JR, Mc Cord JF: Complete ProsthodonticsProsthodontics; Problems, Diagnosis and Management.; Problems, Diagnosis and Management.

MosbyMosby--Wolf, London,Wolf, London, 19961996..

88-- HeartwellHeartwell, C.M. and, C.M. and RhanRhan, A.G.:, A.G.: Syllabus of Complete Dentures.Syllabus of Complete Dentures. 33rdrd ed. Philadelphia, Leaed. Philadelphia, Lea andand

FebigerFebiger;; 19861986..

99-- SharrySharry, J.J.:, J.J.: Complete dentureComplete denture prosthodonticsprosthodontics.. 33rdrd ed.ed. NewYorkNewYork, McGraw, McGraw--Hill;Hill; 19741974..

1010-- SowterSowter,, J.B.:J.B.: Dental laboratory technology:Dental laboratory technology: prosthodonticprosthodontic techniques. Chapel Hill, University of Northtechniques. Chapel Hill, University of North

Carolina;Carolina; 19681968..

1111--WattWatt, D.M. and Mac, D.M. and Mac GregorGregor, A.R.:, A.R.: Designing complete dentures. Philadelphia, W.B. Sounders;Designing complete dentures. Philadelphia, W.B. Sounders; 19761976..

1212-- Winkler,Winkler, S.: Essential of complete DentureS.: Essential of complete Denture ProsthodonticsProsthodontics.. 22ndnd ed. PSG Publishing Company;ed. PSG Publishing Company; 19881988..

1313-- ZarbZarb, G.A.;, G.A.; BolenderBolender, C.L.;, C.L.; HicKeyHicKey, J.C. and, J.C. and carlessoncarlesson, G.E.:, G.E.: Boucher'sBoucher's ProthodonticProthodontic Treatment forTreatment for

Edentulous Patients.Edentulous Patients. 77th.th. Ed. StEd. St--Louis, TheLouis, The C.V.MosbyC.V.Mosby Company;Company; 19901990..

N, B. All pictures inN, B. All pictures in these slidesthese slides are copied from the aboveare copied from the above references and from the internet.references and from the internet.


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bowbow--Importance of the faceImportance of the face

11--IntroduceIntroduce errorserrors inin thethe occlusionocclusion ofof

thethe finishedfinished denturedenture.. 22--AA changechange inin OVDOVD onon articulatorarticulator isispossiblepossible..

33--SupportSupport maxillarymaxillary castcast whilewhilemountingmounting..

mandibular movements f

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