Lecture 3

Question 1

Masseter

Answer 1

Can exert 80KG of force. Strongest muscle in body.

Question 2

Digastric

Answer 2

Pulls - counters masseter

Question 3

Temporalis

Answer 3

Can close, open, move jaw

Question 4

Lateral Pterygoid

Answer 4

Important - inserts into
jaw in a sideways fashion
It pulls itself in anterior fashion,
pulling jaw forward

Question 5

Medial Pterygoid

Answer 5

Muscle that you penetrate

when you give injections

Question 6

Eminence/slope of bone that houses condyle

Answer 6

This prevents 100% forward movement

Everybody differs in degree here- no way to measure outside of surgery, but you can record it somewhat.

Question 7

Terminal hinge axis

Answer 7

where mandible is hinging as it opens and closes. AKA Transverse
horizontal axis.

Question 8

Working side

Answer 8

Side towards which
mandible moves.

This one just moves

Question 9

Non-working side

Answer 9

As this moves right, it moves
medially. Forward, downward,
medial movement.

Question 10

Bennett’s movement

Answer 10

Working condyle moves according to Bennett’s movement within the cone of Bennett.
Bennett movement
= working movement

Question 11

Bennett’s Side Shift

Answer 11

Explain: condyle is not a sphere, it is an oblong structure. Medial part is always backwards
compared to lateral part. Right image is from the top. Rotates as you move. Center shifts to the side
(this is the idea of the cone of bennett). It “pushes itself” in a way.

Question 12

Centric occlusion 90%

Answer 12

90% of patients have a touch first
This point of contact is known as centric occlusion.

As you bite down, you get to maximal intercuspation.

Question 13

Bite

Answer 13

What moves is what really bites. Upper
teeth will brace, lower jaw shoves/cuts
etc.

Question 14

Anterior guidance is dictated by

Answer 14

1. Position of the incisal edge of the mandibular anterior teeth relative to the lingual surfaces of the maxillary anterior teeth
2. Changes in morphology of the lingual surfaces of maxillary anterior teeth.
3. Length of mandibular incisors or canines

Question 15

Anterior Guidance

Answer 15

Incisal guidance
2. Canine guidance

Missing anterior guidance, have group function (molar contact)

Question 16

The incisal guides on the articulator serve three functions:

Answer 16

1. When anterior teeth are prepared, the angulation of the custom guide provides anterior guidance in place of the anterior teeth.
2. When only posterior teeth are to be replaced, the angulation of the guide serves to estimate the buccolingual and mesiodistal cusp angles, so as to avoid interferences in both protrusive and non-working excursions.
3. Reduce the amount of wear of the stone casts during excursive movements made on the articulator.