Occlusion for conventional dentures

Question 1

What are the different types of record block?

Answer 1

• wax only
• shellac base with wax
• heat cured base

Question 2

What are the properties of a wax only record block?

Answer 2

• less retentive
• cheap
• lots of space for setting teeth

Question 3

What are the properties of a shellac base record block?

Answer 3

• more stable
• more expensive
• limited space for setting teeth

Question 4

What are the properties of a heat cured base?

Answer 4

• very stable
• expensive
• least space for setting teeth

Question 5

What equipment is required for a jaw registration?

Answer 5

• heat source
• hot plate
• wax knife
• foxes bite plate
• dividers or willis bite gauge
• bite registration paste

Question 6

What are the steps of jaw registration?

Answer 6

1 - adjust upper for retention
2 - adjust upper for tooth position
3 - adjust upper for occlusal plane
4 - lower tooth position and jaw relationship
5 - measure vertical dimension and establish face height
6 - record registration
7 - select shade, mould and setting

Question 7

How should you adjust a record block for retention?

Answer 7

• not too much lip support (or else will drop)
• trim rim labially and buccally
• ensure no overextension

Question 8

How should you adjust the upper record block for tooth position?

Answer 8

• lip support
• incisal level
• midline
• buccal corridor
• occlusal plane

Question 9

What is the recommended nasiolabial angle for lip support?

Answer 9

90 degrees (actually usually 96 degrees)

Question 10

What should be marked on to the record block for tooth position and incisal level?

Answer 10

• smile / lip line
• canine line

Question 11

What should be used as reference for the midline?

Answer 11

• incisive papilla
• filtrim of the lip
• nose to some extent

Question 12

What is the buccal corridor?

Answer 12

• space between cheeks and teeth when smiling
• in a small percentage of people

Question 13

What reference points are used to adjust the occlusal plane?

Answer 13

Anterior = interpupillary
Posterior = ala tragus line

Question 14

What is the neutral zone?

Answer 14

The area in which the forces of the lips and cheeks, and the tongue are balanced, denture should be placed here.

Question 15

What happens if a denture is not designed within the neutral zone?

Answer 15

Too buccally - cheek movement dislodges denture
Too lingually - tongue movement dislodges denture
Lingual flange incorrect shape - tongue lifts denture

Question 16

Define class I skeletal relationship.

Answer 16

Shallow overjet and overbite

Question 17

Define class II div 1 skeletal relationship.

Answer 17

Increased overjet and shallow overbite

Question 18

Define class II div 2 skeletal relationship.

Answer 18

Increased overjet and deeper overbite

Question 19

Define class III skeletal relationship.

Answer 19

Edge to edge incisors or reverse overjet ± posterior cross bite

Question 20

What happens when there is excessive freeway space?

Answer 20

• reduced masticatory function
• overclosed facial appearance
• cheek biting
• TMJ symptoms

Question 21

What happens when there is reduced or inadequate freeway space?

Answer 21

• excessive load on denture bearing area
• continuous muscular activity results in pain
• aesthetic complaints (“teeth are too big”)
• noisy dentures

Question 22

What is the ideal FWS?

Answer 22

• 2-4mm
• don’t change more than 1-2mm from patients initial FWS even if it is not in the recommend range

Question 23

How do you prepare a record block to record registration?

Answer 23

• cut notches
• apply adhesive if using paste