Retention and Stability of Complete Dentures

Question 1

What are the different displacing forces of a denture?

Answer 1

Gravity
Muscle activity
Sticky foods
Functional movements

Question 2

What is adhesion?

Answer 2

The physical attraction of unlike molecules for each other
Eg - between saliva and mucous membranes or saliva and denture base

Question 3

Which arch is adhesion most important in?

Answer 3

Maxillary - the larger area of adhesion the better retention

Question 4

What is cohesion?

Answer 4

The physical attraction between similarly molecules
Eg - salivary film

Question 5

What affects atmospheric pressure in complete dentures?

Answer 5

Good extension and a border seal

Question 6

How should a denture fit the basal surface to help retention and stability?

Answer 6

Full coverage of the denture bearing area - extend onto pear shaped pad
Post dam seal for the maxillary denture
Use of undercuts
Use of altered path of insertion

Question 7

What may make retention and stability difficult in complete dentures?

Answer 7

Strophic ridges
Developmental defects eg - congenital cleft
Fibrous ridge
Damaged alveolar ridge
Patients with mobile soft tissue
Patients who can’t tolerate base extension eg - gagging
Insufficient saliva

Question 8

How should teeth be positioned to aid retention and stability?

Answer 8

Drop the occlusion plane so the tongue can get over the top so it doesn’t move the denture left to right
Place the teeth in the neutral zone - over the residual ridge

Question 9

Describe an errors in tooth positioning

Answer 9

Lingual overhangs make the dentures unstable

Question 10

What happens to the polished surfaces of complete dentures?

Answer 10

Contouring of buccal and lingual palatal shapes
Better tongue space will compromise ridge stability
Can remove 7s for better tongue space

Question 11

What are aids to denture retention and stability?

Answer 11

Denture adhesives
Linings
Implants