Occlusion

Question 1

What is occlusion

Answer 1

The study of the relationships between the upper and lower teeth when they are closed together

Question 2

What is the functional purpose of bringing teeth together

Answer 2

For chewing and for swallowing

Question 3

What does occlusion involve

Answer 3

The masticatory system:
Teeth
Periodontal tissues
Jaws
TMJ
Muscles
Nervous control

Question 4

How are the teeth positioned most of the time

Answer 4

Teeth are apart

This position is called the returned contact position

Question 5

What is the intercuspal position

Answer 5

The position when the mandible is maximally braced against the maxilla

Question 6

Why is the retruded contact position sometimes used over the intercuspal position

Answer 6

It is sometimes used for dentures when there is not enough teeth for the intercuspal position

Question 7

What are the cusps that occlude in the posterior teeth

Answer 7

The lower buccal and the upper palatal cusps

Question 8

What do the posterior cusps occlude against

Answer 8

The fossa and marginal ridges of the opposing teeth

Question 9

What do the lower incised edges and canine tips occlude against

Answer 9

The cingulum of the opposing teeth

Question 10

In what direction does an ideal occlusal contact direct forces

Answer 10

Down the long axis of teeth

Question 11

What is articulating paper for

Answer 11

It assesses whether the patients have a good and balanced occlusion ICP contacts are marked

Question 12

What are the teeth maintained in position by

Answer 12

Contact with teeth in the opposing arch
Contact with adjacent teeth in the same arch
Soft tissues

Question 13

What can happen to teeth if there is no opposing tooth

Answer 13

Over eruption

Question 14

Why can over eruption be an issue

Answer 14

It can harm the opposing soft tissues

Question 15

What is the sideward movement of the mandible from a medial occlusal position characterised by

Answer 15

Downward, forward and inward translation of the contralateral condyle
The i-is lateral side of the movement results in the condyle rotating about an axis

Question 16

What is guidance

Answer 16

The tooth contacts that occur in lateral movements of the mandible

Question 17

How is guidance studied

Answer 17

Observing movements of the mandible from ICP outwards

Question 18

What are the different types of guidance

Answer 18

Canine

Group function

Question 19

What is an articulator

Answer 19

Device in which dental casts are held in relationship to each other and can replicate mandibular movements

Question 20

What are the basics in an examination of occlusion

Answer 20

Are there irregularities in tooth position in each arch that may impact occlusion
Is the ICP stable
What are the contacts in ICP
Which teeth provide guidance

Question 21

What are the different types of tooth wear

Answer 21

Attrition
Erosion
Abrasion

Question 22

What is attrition

Answer 22

Loss of tooth substance caused by contact between occluding surfaces

Question 23

What is attrition often caused by

Answer 23

Parafunctional activity - purposeless clenching and grinding of the teeth

Question 24

What is erosion

Answer 24

Loss of tooth substance by a chemical process not involving bacterial action

Question 25

What are the sources of erosion

Answer 25

Diet Regurgitation Environmental

Question 26

What is abrasion

Answer 26

Loss of tooth surface caused by abnormal rubbing from a non dental object often a tooth brush

Question 27

Why may restorations fail

Answer 27

Secondary caries fracture the restoration or tooth pulp death Incompatibility with periodontal tissues Poor appearance

Question 28

What should in intra/extra oral exam include

Answer 28

Assessment of the occlusion - both static and functional Looking for signs of tooth wear Evaluation of existing restorations

Question 29

What is the feedback system

Answer 29

When the teeth touch, a signal is sent to the brain to tell that the teeth are touching. The feedback system regulates the intensity of force applied to the teeth. The neuromuscular system that regulates these forces and jaw movements relies on proprioceptive input from the PDLs, tooth pulps, TMJ, muscles, tendons and ligaments

Question 30

What is a shim stock for

Answer 30

Asseses whether a patient has good occlusion and whether it is balanced or not It is very thin You may not be able to remove it due to the maximum intercuspation and we want the right and left to be balanced

Question 31

What should be present in a balanced occlusion

Answer 31

Even, bilateral contact points in ICP Anterior teeth contacts evenly when the mandible protrudes Contact with teeth in the opposing arch Contact with teeth in the same arch

Question 32

What is canine guidance

Answer 32

If when you slide your teeth to the left and right, only the canines contact This is good as canines are excellent at coping with lateral forces

Question 33

What is group function

Answer 33

If when you slide your teeth to the left and right, a number of teeth are in contact all sharing the load

Question 34

When may group function be present

Answer 34

When canines are worn down or crooked

Question 35

Why is canine guidance more ideal than group function

Answer 35

Heavier loads should ideally be near the anterior teeth and lighter loads at the back