Occlusion Overview

Question 1

What is the definition of a stable occlusion?

Answer 1

When the teeth occlude such that the possibility of movement (tilting, drifting and over-eruption) is minimised

Question 2

What is the definition of intercuspal position?

Answer 2

Maximum interdigitation of teeth, most comfortable bite, OVD measured in this positon

Question 3

What is the definition of edge-edge position?

Answer 3

Teeth slide forward from ICP (guiding on palatal sufaces of ant teeth), upper and lower incisal edges of upper and lower touching

Question 4

What is the definition of protrusion position?

Answer 4

• mandible slides anteriorly to maximum limit (movement controlled by lateral pterygoid mainly)
• Condyle moves forwards & downwards on articular eminence
• No posterior tooth contacts

Question 5

What is the definition of maximal opening position?

Answer 5

Full translation of the condyle over the articular eminence (no teeth in contact)

Question 6

What is the definition of retruded axis position?

Answer 6

• Terminal hinge axis position
• Most superior anterior position of the condylar head in the fossa

Question 7

What is the definition of retruded contact position?

Answer 7

• First tooth contact when the mandible is in the retruded axis position
• Approx. 1mm posterior to ICP

Question 8

What is the Bennet angle?

Answer 8

The path of the non-working condyle in the horizontal plane during lateral excursion (typically 1-4mm)

Question 9

What is canine guidance?

Answer 9

On lateral excursion, the canines remain in contact and cause disclution of the rest of the teeth on the working & non-working side

Question 10

What is group function?

Answer 10

Simultaneous contact between multiple maxillary and mandibular teeth on lateral excursion

Question 11

How does the conformative occlusion approach differ from the re-organised approach?

Answer 11

Conformative = restoration provided are designed in accordance with the existing jaw relationship

Re-organised = when ICP cannot reliably be established, occlusal scheme is redesigned in the retruded contact position (as its the most reproducible contact point)

Question 12

What are examples of different types of articulators?

Answer 12

• Arcon
• Average Value
• Semi-Adjustable

Question 13

On an average value articular what are the Bennet and Condylar Guidance Angles set to?

Answer 13

Bennet = 15 degrees
Condylar Guidance Angle = 30 degrees

Question 14

What are the different parts of a facebow?

Answer 14

• reference plane locator
• bite fork
• transfer jig assembly
• earbow

Question 15

When do we not used the conformative approach in restorative dentistry?

Answer 15

• An increase in vertical height is needed to make space for restorations
• Tooth/teeth significantly out of position
• A significant change in appearance is wanted
• History of occlusal related failure/fracture of existing restorations

Question 16

When using a facebow, where is the anterior reference point?

Answer 16

43mm apical to incisal edge of upper lateral incisor

Question 17

What does a facebow record?

Answer 17

the spatial relationship of the maxillary arch to the temporomandibular joints (TMJs) and the hinge axis of the mandible

Question 18

What are the uses of a facebow?

Answer 18

• accurately mount casts on articulators
• investigate the relationship of the maxilla to the terminal hinge axis of mandible

Question 19

Describe four materials used to help mount casts in ICP?

Answer 19

1. No material = plenty of tooth contacts so ICP is obvious
2. Wax wafer = place wax over biting surfaces and get patient to bite down (ensure thin)
3. Registration paste = place bite reg paste over occlusal biting surfaces and get pt to bite down
4. Record blocks = when free end saddles present and casts cannot be hand articulated (use this with bite reg paste)