5 - Retention and stability of complete dentures Flashcards
1
Q
Define retention.
A
Resistance of denture to vertical movement away from tissues
2
Q
Define stability.
A
Resistance of denture to lateral displacement (by functional forces)
3
Q
Define adhesion.
A
- physical attraction of unlike molecules for each other (saliva and mucous membrane/saliva and denture base)
- “suction”
4
Q
How does adhesion affect denture design?
A
- more important in the maxillary than the mandibular
- extension over denture bearing area
5
Q
Define cohesion.
A
Physical attraction between similar molecules (salivary molecules)
6
Q
What is the role of saliva in denture wearing?
A
- buffering
- cleaning (antimicrobial)
- adhesion and cohesion
7
Q
How does atmospheric pressure affect denture design?
A
Border seal ensures good “suction”
8
Q
Describe a post dam seal.
A
- bevelled edge at the beginning of the soft palate
- only in maxillary denture
- ensure fovea palatine are not covered
- 0.5mm is typical depth
9
Q
Describe adequate extension of a lower denture.
A
- base extends over retromolar pads
- should extend into lingual pouch (where you can palpate the vertical part of the mandible)
10
Q
Where are soft tissue undercuts common?
A
- anterior 4-4 maxillary region
- uncommon in lower
11
Q
List factors that can make retention difficult.
A
- atrophic ridges (down to basal bone)
- incomplete palate (cleft palate or cancer patients)
- fibrous ridges
- damaged alveolar ridges (soft tissue graft)
- gagging patients
- insufficient saliva
12
Q
How should teeth be positioned?
A
- teeth in neutral zone
- over ridge in mandible
- slightly buccal in maxilla
- narrower teeth are better
13
Q
How does the tongue affect denture wearing?
A
Teeth that are placed too lingually cause the denture to lift
