Occlusion and Restorative Dentistry 1

Question 1

What is the function of the temporalis?

Answer 1

Anterior fibres elevate the mandible
Posterior fibres retrude the mandible

Question 2

What is the function of the lateral pterygoid?

Answer 2

Depresses and protrudes the mandible

Question 3

What is the function of the medial pterygoid?

Answer 3

Elevates and protrudes the mandible
Assists in lateral movement

Question 4

What is the function of the masseter?

Answer 4

Elevates and protrudes the mandible
Assists in lateral movement

Question 5

Describe rotation of the mandible?

Answer 5

Small amount of mouth opening (up to 20mm)
Condyle and disk remains within the articular fossa
No downwards or forwards movement
Also known as hinge movement

Question 6

What are hinge movements?

Answer 6

Rotation of the condylar heads around an imaginary horizontal line
This line is called the terminal hinge axis

Question 7

What is a face bow used for?

Answer 7

Records the terminal hinge axis and distance between the condyles

Question 8

Describe translation of the condyle?

Answer 8

Lateral pterygoid contracts
Articular disc and condyle begin to move
Condyle travels downwards and forwards along the artificial eminence
May also travel laterally

Question 9

What is Posselts Envelope?

Answer 9

Describes the extremes of mandibular border movement

Question 10

What symbols are involved in Posselts Envelope?

Answer 10

ICP = Intercuspal Position
E = Edge to Edge
Pr = Protrusion
T = Maximum opening
R = Retruded Axis Position
RCP = Retruded Contact Position

Question 11

What is Intercuspal Position (ICP)

Answer 11

Tooth position regardless of the condylar position
The comfortable bite with maximum interdigitation of the teeth
Also called centric occlusion (CO)

Question 12

What is Edge to Edge?

Answer 12

Teeth slide forwards from ICP so incisal edges of upper and lower incisors touch

Question 13

What is protrusion?

Answer 13

Condyle moves forwards and downwards on articular eminence
Only incisors and/or canines touch
No posterior tooth contacts
Eventually no tooth contacts

Question 14

What is maximum opening?

Answer 14

No tooth contacts
Mouth wide open
Full translation of the condyle over the articular eminence

Question 15

What is retruded axis position?

Answer 15

No tooth contacts
Most superior anterior position of the condylar head in the fossa
Terminal hinge axis

Question 16

What is retruded contact position?

Answer 16

First tooth contact when the mandible is in retruded axis position

Question 17

What is ICP-RCP slide?

Answer 17

ICP is approx 1mm anterior to RCP in 90% of the population
The mandible slides forwards from RCP to achieve ICP

Question 18

Describe lateral translation?

Answer 18

The side the mandible is moving to is the working side
The side the mandible is moving away from is the non-working side
The lateral pterygoid of the non-working side contracts as the mandible moves
Also known as Bennet movement

Question 19

What is the Bennet angle?

Answer 19

The path of the non working condyle in the horizontal plane during lateral excursion