Quiz 6 stuff - Basic Mandibular Movements

Question 1

Centric Relation (CR)

Answer 1

Maxillomandibular relationship, independent of tooth contact.

Condyles articulate in the ANTERIOR-SUPERIOR POSITION against the posterior slopes of the articular eminences.

From this unstrained, physiologic maxillomandibular relationship. Good reference position.

When in centric relation, can only do pure rotation only.

Question 2

what is position of the condyle in centric relation?

Answer 2

anterior-superior

centric relation = when the condyle is seated in the glenoid fossa in the most anterior/superior position

Question 3

Digastric / Supra and infrahyoid do what?

Answer 3

Help with opening. Muscles below the jaw, below the mandible to pull the mandible down.

Depression of mandible (opening)
results in rotation of the condyle.

Question 4

Which muscles are going to help function during retrusion?

Answer 4

Posterior temporalis

Question 5

Which muscles are going to help function during protrusion?

Answer 5

Lateral Pterygoid

Question 6

When you open wide, which muscles are activated?

Answer 6

lateral pterygoid (gliding movement)

supra and infrahyoid

Question 7

Which muscles do rotation?

Answer 7

supra and infrahyoid only.

Question 8

Which muscles help when biting down?

Answer 8

Masseter, Temporalis, and medial pterygoid.

Question 9

Transverse Horizontal Axis:

Answer 9

Imaginary line goes through both condyles, which mandible may rotate within the sagittal plane.

AKA hinge axis.

Question 10

Working vs non-working sides

Answer 10

Working side: teeth occluding together, side where mastication (chewing) occurs.

non-working side: mastication does not occur.

Question 11

Right working movement, what happens?

Answer 11

Activation of LEFT lateral pterygoid
movement of mandible on RIGHT
mastication occurs on RIGHT

LEFT condyle translating
RIGHT condyle rotating.

Question 12

Bilateral Balanced Occlusion:

Answer 12

Both sides have posterior occlusal contact in MIP and eccentric positions.
Causes excessive wear to natural teeth (not recommended)
good for dentures

Question 13

Why we use bilateral balance occlusion for removable prosthetics?

Answer 13

To maintain stability of our prosthesis. Don’t need this for natural teeth bc they are anchored into the bone via the PDL, so we don’t need to stabilize the lining anyways.

Question 14

When do you want to make MIP during CR?

Answer 14

for dentures for bilateral balance occlusion.

Question 15

Group function:

Answer 15

Multiple contact relations between max / mand teeth in lateral movements on WORKING SIDE only.

“unilaterally” balanced.

very common. Distributes the occlusal load among teeth on the working side. Sharing the load.

Question 16

Guidance:

Answer 16

Provides regulation / direction to movement. basically guiding it.

Question 17

Anterior Guidance:

Answer 17

influence of the contacting surfaces of anterior teeth, limiting mandibular movements.
anterior teeth prevent posterior tooth contact

Right working anterior guidance: 6 and 27 shud be in contact
Left: 11 and 22. CANINES

Question 18

Mutually protected Occlusion:

Answer 18

occlusal scheme in which posterior teeth prevent excessive contact of the anterior teeth in MIP., and anterior teeth disengage posterior teeth in all mandibular excursive movements.

Question 19

Class I lever:

Answer 19

Similar to crowbar. Most powerful class

Power -> Fulcrum -> Work

Question 20

Class II lever:

Answer 20

Similar to wheelbarrow / nutcracker

Fulcrum -> Work -> Power
Condyle -> 2nd/3rd molars -> Muscle

Only applies to 2nd / 3rd molars

Question 21

Class III lever:

Answer 21

Most common lever system for human dentition.

Similar to drawbridge / chopsticks

Fulcrum -> Power -> Work
Condyle -> Muscle -> Anterior teeth

Question 22

Criteria for Optimum occlusion:

Answer 22

perio very important for stability
Anterior guidance in harmony with the border movements of envelope of function
disclusion of posterior teeth