Occlusion 2 - Dynamic and Static Occlusal Contacts

Question 1

What articulating paper should be used to mark tooth contacts ?

Answer 1

40 microns.
Can use two different colours to mark dynamic or static contacts.

Question 2

What are Millers forceps ?

Answer 2

For holding articulating paper to record tooth contacts.

Question 3

When should tooth contacts be marked ?

Answer 3

Before preparing tooth or removing restoration.
After placement of crown or restoration.

Question 4

Define functional cusps.

Answer 4

Cusps that occlude with opposing teeth in ICP i.e. lingual cusps of upper posterior teeth and buccal cusps of lower posterior teeth.

Question 5

Define non-functional cusps.

Answer 5

Cusps that do not occlude with opposing teeth in ICP i.e. buccal cusps of upper posterior teeth and lingual cusps of lower posterior teeth.

Question 6

Define fossa.

Answer 6

Depression or concavity on tooth surface i.e. where functional cusp of tooth contacts the fossa of the opposing tooth.

Question 7

What are possible problems in static occlusion ?

Answer 7

Incisor relationship.
Overbite.
Crossbite.
Overjet.
Open bite.

Question 8

What classification is used to describe incisor classification ?

Answer 8

Angles classification.
Class I, Class II div 1, Class II div 2, Class III.

Question 9

What is the difference between Class II div 1 vs. Class II div 2 ?

Answer 9

Class II div 1 - overjet.
Class II div 2 - overbite.

Question 10

Define overbite.

Answer 10

Vertical overlap of incisors.

Question 11

What is normal value of overbite ?

Answer 11

2-4mm.

Question 12

Define overjet.

Answer 12

Relationship between upper and lower teeth in horizontal plane.

Question 13

Define crossbite.

Answer 13

Can be anterior or posterior.
Condition where one or more teeth may be abnormally malpositioned buccal or lingually or labially with reference to opposing teeth.

Question 14

Define anterior open bite.

Answer 14

Lack of vertical overlap of anterior teeth when posterior teeth are in full occlusion.

Question 15

What can cause anterior open bite ?

Answer 15

Digit sucking.
Instrument players.
Anatomical abnormalities preventing development of maxilla.

Question 16

Define posterior open bite.

Answer 16

Failure of contact between the posterior teeth when the teeth are in full occlusion.

Question 17

Why is canine guidance preferable ?

Answer 17

Longest and largest roots (crown/root ratio).
Dense compact bone supporting tooth.
Fewer muscles active when canines contact during eccentric movements.
Dissipate horizontal forces while disoccluding posterior teeth.

Question 18

What is canine guidance i.e. mutually protected occlusion ?

Answer 18

When mandible moves laterally, contact remains only between canines with no posterior tooth contacts (freeway space).

Question 19

Define freeway space.

Answer 19

Lack of posterior tooth contacts during canine guidance latero-excursive movements.

Question 20

What are the four parts to a ‘gold standard’ mutually protected occlusion ?

Answer 20

Canine guidance.
Posterior disclusion in lateral excursions.
No non-working or working side contacts.
No protrusive interferences.

Question 21

Define group function.

Answer 21

Multiple teeth remain in contact on later-excursive movements of mandible.

Question 22

Define protrusion.

Answer 22

Condyle moves forwards and downwards on articular eminence.

Question 23

What tooth contacts should be seen in ‘gold standard’ occlusion when mandible in protruded position ?

Answer 23

Only incisors (+/- canines) in contact.
No posterior tooth contacts.

Question 24

Define occlusal interference.

Answer 24

Undesirable tooth contacts that may produce mandibular deviation during closure to ICP or may hinder smooth passage to and from ICP.

Question 25

What are two types of bruxism ?

Answer 25

Eccentric - dynamic position - parafunctional grinding of teeth.
Centric - static position - clenching.

Question 26

What are clinical signs and symptoms of bruxism ?

Answer 26

Toothwear - shortened crowns and loss of occlusal tooth anatomy.
Fractured restorations.
Tooth migration.
Tooth mobility in absence of periodontal disease.
Muscle pain and fatigue.
Headache or earache.
Pain or stiffness around TMJ and surrounding muscles.

Question 27

Define fremitus.

Answer 27

Palpable or visible movement of a tooth when subjected to occlusal forces.

Question 28

Define primary occlusal trauma.

Answer 28

Intact periodontium and movement of teeth due to occlusal trauma.

Question 29

Define secondary occlusal trauma.

Answer 29

Reduced periodontium and movement of teeth due to occlusal trauma.

Question 30

What are the six components to examination checklist of assessment of occlusion ?

Answer 30

Incisor relationship.
Guidance.
Overjet/overbite.
ICP contacts.
Working, non-working and protrusive contacts.
Pathology.