Retention and stability of complete dentures

Question 1

Define retention

Answer 1

Resistance of the denture to vertical movement away from the tissue

Question 2

Define Stability

Answer 2

Resistance of the denture to displacement by functional forces

Question 3

List the important retentive features of the denture

Answer 3

• Border seal
• Appropriate extension to undercuts
• Saliva
• Quality and size of denture bearing area
• Fit of denture to the impression surface

Question 4

How to achieve a complete border seal

Answer 4

Achieved by extending flanges to the full depth of the sulcus
Addition of a post-dam

Question 5

What is the post-dam

Answer 5

Posterior aspect of upper denture should extend to the junction between soft and hard palate (the tissue is displaceable but not moveable)

Question 6

Maxillary landmarks for extension of denture

Answer 6

Extend posterior aspect to the maxillary tuberosities as a bony undercut for retention

Question 7

Mandibular landmarks for extension of denture

Answer 7

Extend posteriorly to the retromolar pad for enhanced retention

Question 8

Saliva - factors to account for

Answer 8

Quantity - too much or too little can influence retention

Quality - too thin or too thick

Question 9

Ideal saliva for retention

Answer 9

Serous with good surface tension and an adequate supply

Question 10

Tissue factors affecting retention

Answer 10

Severely resorbed ridges

Fibrous ridges