TEMPROMANDIBULAR JOINT AND MOVEMENTS MANDIBULAR [ T M J ]

TEMPROMANDIBULAR JOINT ANDMOVEMENTS MANDIBULAR

[T M J]

1. Is the articulation between the mandible and the cranium .

2. It is a bilateral articulation .

AnatomyAnatomy1. Articular fossa and

eminence .

2. Condylar head .

3. Articular disc (meniscus).

4. Articular capsule (capsular ligament) .

5. TMJ ligament .

6. Synovial membrane .

Muscles of mastication

1. Temporalis .

2. Masseter .

3. Medial pterygoid .

4. Lateral pterygoid .

Temporalis

Masseter

THE BASIC MOVEMENTS OF THE MANDIELE

1. Rotation Movement

= hinge movement .

1. Translation Movement

(gliding movement.)

Hinge movement = rotationHinge movement = rotation Rotation movement =

hinge movement.

It is the rotation of the

mandible around an

imaginary hinge axis at

the centers of the

condyles. It occurs in the lower

compartment of the joint

Gliding or translationGliding or translation

It is the body movement of the mandible.It occurs in the upper compartment.

Condyle in retroded .no movement position

Condyle performing rotation=hinge movement Condyle

performing anterior translation=gliding.

intercusbal intercusbal position from position from which hinge which hinge movement will movement will startstart

No TranslationNo Translation

Sagittal view=lateral view

TranslationTranslation

Protrosion movementProtrosion movement

It is the forward movement of the mandible.

The mandible does not move in pure forward movement.

The mandible moves down ward and forward = Gliding = translation movement.

It occurs when the mandible moves from retroded position to -edge to edge position- to- reverse over jet, of anterior teeth.

Excursive MovementsExcursive Movements

Protrusive – No Posterior Contact

The lower anterior teeth ride up the lingual of the maxillary anterior teeth as the jaw goes forward.

Incisal pathIncisal path

Condylar pathCondylar path

Condylar path inclination varies according to the amount of protrusion. a-b Sagittal condylar path inclination. Centric relation position of the condyle. 4-P. 4 mm protrusion.8P. 8 mm protrusion

No TranslationNo Translation

TranslationTranslation

Posselt’s Posselt’s FigureFigure

MP

MO

ICPRCP

HA

MP = Maximal protrusion

ICP = Intercuspal position

RCP= Retruded Contact position

HA = Hinge axis

MO = Maximum opening

EE=edge to edge

Posselt’s Figure

Habitual Arc of ClosureHabitual Arc of Closure

Edge to edge position.

Christensen Phenomena When the mandible moves to edge to edge position , separation occurs distally between the natural dentition or occlusion rims .

Protrusive

Record

The protrusive relationship determines the angle of the horizontal condylar path

Anterior biting to reverse vertical overlap.

Lateral Movement .Working side = the side which the movement take place

Lateral Movement. ) non working side =the side which the

mandible moves away from.

Lateral movement of the mandible

The Condylar Path

1. Horizontal Condylar Path .

2. Lateral Condylar Path .

3. The Condylar Path Angle .

22 . .Vertical relationsVertical relations..

Vertical Dimension of rest

The vertical dimension of the face when the mandible is in rest position.

Vertical Dimension of occlusion

The vertical dimension of the face when the teeth are in contact in centric occlusion.

Freeway space= V.D.R. – V.D.O. = 2-4mm

The centric relationThe centric relation

It is the relation between the mandible and the maxilla when the mandible in the physiologic retroded position at the vertical dimension of occlusion.

Importance: it is the point from which all movemnt of the mandible will start and end must be recorded to arrange the teeth in this position

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