Mechanisms of Mandibular Movement

Question 1

What are the 4 anatomic determinants of movement?

Answer 1

Right TMJ
Left TMJ
Teeth/Occlusion
Neuromuscular

Question 2

Which axis of the mandible is the most basic fundamental?

Answer 2

Hinge Axis

Question 3

___ is the imaginary line drawn between the 2 condyles where the mandible will open and close about this axis

Answer 3

Hinge Axis

Question 4

_____ is the movement of the mandible forward until front teeth come into contact

Answer 4

Protrusion

Question 5

What muscles are involved in protrusion?

Answer 5

lateral pterygoid; assisted by medial pterygoid

Question 6

What muscles are involved in retraction?

Answer 6

Posterior fibers of temporalis, deep masseter, and geniohyoid and digastric

Question 7

What muscles are involved in elevation?

Answer 7

Temporalis, masseter, and medial pterygoid

Question 8

What muscles are involved in depression?

Answer 8

digastric, geniohyoid, and mylohyoid muscles

Question 9

What are the 2 movements of lateral movements of mandible?

Answer 9

Rotation and translation

Question 10

Which condyle rotates in lateral movement?

Answer 10

Working condyle (side toward which the mandible is moving

Question 11

Which condyle translates in lateral movement?

Answer 11

Non-working/ Balancing condyle

Question 12

T/F: Many of the terms and words of occlusion originated with the construction of denture

Answer 12

True

Question 13

____ occurs when condyles move down articular eminence

Answer 13

Translation

Question 14

_____ occurs for the first 20-25mm of opening

Answer 14

Rotation

Question 15

Only _____ movement can be isolated clinically

Answer 15

rotational movement

Question 16

_____ movements may occur in all three reference planes in the mandible

Answer 16

Rotational movements

Question 17

What are the 3 planes rotation can occur?

Answer 17

Sagittal, frontal, and horizontal

Question 18

_____ in the vertical plane around a sagittal center of rotation Occurs during lateral movement Sagittal axis is in the working side condyle; Non-working side moves inferiorly in the frontal plane around sagittal axis

Answer 18

Rotation

Question 19

____ in the horizontal plane around a frontal (vertical)axis; Frontal axis is in the working side Occurs during lateral movement; non working moves medially and forward in the horizontal plane around this frontal axis

Answer 19

Rotation

Question 20

Where all three axes (horizontal,vertical and sagittal) meet is called the ______

Answer 20

rotational center of the condyle

Question 21

To do a protrusive movement, both _____ contract to move mandible forward

Answer 21

Lateral pterygoids

Question 22

What muscle functions in translation?

Answer 22

Lateral pterygoids

Question 23

In what movement do Both condyles translate; Condyles move forwards and downwards; Condyles move down the posterior slope of the articular eminence

Answer 23

Protrusive movement

Question 24

The ______ is the only joint in the body capable of moving in three dimensions.

Answer 24

temporomandibular joint

Question 25

When a condyle moves in a _______, it goes over the medial wall of the glenoid fossa

Answer 25

Lateral translation

Question 26

During, the angle is influenced by the ______ of the articular eminence.

Answer 26

posterior slope

Question 27

The condylar angle measured via lateral movement is influenced by the ______ of the articular fossa (non-workingside)

Answer 27

steepness of the medial wall

Question 28

once the condyle begins to move in any direction, it is no longer ______, it will begin to move either forward or laterally in the fossa.

Answer 28

rotating

Question 29

An immediate lateral shift of the working condyle is called

Answer 29

Immediate side shift

Question 30

A slower lateral shift of the working condyle is called

Answer 30

Progressive side shift

Question 31

During a lateral movement, this is the condyle on the side towards which the mandible moves–A.k.a. rotating condyle

Answer 31

Working side condyle

Question 32

This is the condyle on the side opposite to which the mandible moves–A.k.a. orbiting condyle

Answer 32

Non-working side condyle

Question 33

_____ condyle moves downwards, forwards and medially Moves over the steeper medial wall of the articular fossa; Can record the condylar angle from this movement also; Condylar angle is usually slightly steeper than when recorded in protrusion

Answer 33

Non-working side condyle

Question 34

_____ condyle mainly rotates around a vertical axis (it does not move out of the articular fossa)

Answer 34

Working side condyle

Question 35

Sometimes the orbitingside condyle does not simply rotate but also shifts laterally during the lateral movement.This lateral movement of the orbiting side condyle is called the _______

Answer 35

Bennett movement.

Question 36

Bodily shift of the mandible toward the working side during lateral excursion

Answer 36

Bennet's movement

Question 37

The _____ the teeth are to the working condyle, the shorter will be the cusp height

Answer 37

closer

Question 38

______ is the angle formed by the sagittal plane and the path of the advancing orbiting condyle during lateral mandibular movement as viewed in the horizontal plane.

Answer 38

Bennett angle:

Question 39

Angle at which the condyle moves away from a horizontal reference plane; can be recorded (estimated) on a patient; Can be recorded via a protrusive movement or via lateral movements

Answer 39

Condylar angle

Question 40

What is the plane of reference for the condylar angle?

Answer 40

Frankfort's horizontal plane

Question 41

_____ is The angle formed by the intersection of the protrusive and non-working condylar paths as viewed in the sagittal plane.

Answer 41

Fischer’s angle

Question 42

The difference between the condylar angle recorded with a protrusive and lateral record; Medial wall of articular fossa is generally steeper than the posterior slope of the articular eminence (5-10°0

Answer 42

Fischer's angle

Question 43

The dynamic relationship of the lower anterior teeth against the upper anterior teeth through all ranges of function

Answer 43

Anterior guidance

Question 44

What are the only 2 teeth you want touching during lateral protrusive?

Answer 44

Canines

Question 45

What are the teeth you want touching during protrusive movements?

Answer 45

Incisors

Question 46

_______ protect the posterior teeth in all mandibular excursions

Answer 46

Anterior teeth

Question 47

____ protect anterior teeth by taking the force of closure of the mandible

Answer 47

Posterior teeth

Question 48

Class ___ lever will create the least stress to the anterior teeth

Answer 48

Class 3

Question 49

The closer to the fulcrum a tooth is, the ____ force it will have

Answer 49

More force

Question 50

If a posterior nonworking contact occurs during the protrusive biting function, the fulcrum point moves from the temporomandibular joint to the point of faulty contact, forming the Class ____ lever

Answer 50

Class 1 lever

Question 51

The premature nonworking contact (B) triggers a more forceful closure of the muscles (P) on the nonworking side. This changes the normal Class III lever system to the destructive Class ____ lever system and puts an unusual amount of stress on the undesired contact.

Answer 51

Class 2 lever

Question 52

The amount of _____ that can be generated between the teeth depends on the distance from the temporomandibular joint and the muscle force vectors. Much more force can be generated on the posterior teeth, than on the anterior teeth.

Answer 52

force