CD - security and liners

Question 1

What is the pt’s main concern with dentures?

Answer 1

Denture security

Question 2

What is retention?

Answer 2

Ability to resist forces attempting to displace the denture at right angles to supporting tissues
Effectiveness of fitting surface and peripheral seal

Question 3

What is stability?

Answer 3

Ability to resist those forces attempting to displace it in directions, other than at right angles to supporting tissues
Size and shape of residual alveolar ridge

Question 4

What to consider with denture security?

Answer 4

Retention
Stability
Occlusal, polished and fitting surfaces
Cause of muscle displacement - wide sulcus

Question 5

What are the types of denture liners?

Answer 5

Permanent
- Heat cured PMMA
- Autopolymerising PMMA
Semi-permanent
Temporary

Question 6

Features of permanent liners?

Answer 6

If orifice exposed/bony ridge
Improves shape of fitting surface for better fit
May be hard of soft
Friable but well lubricated mucosa
Habituated pt
Obturators - to facilitate cleft palate or surgical removal of tumour, forms bung that seals hole in hard palate, softer than laboratory cured, more compatible with mucosa

Question 7

Permanent liners - Heat cured PMMA features?

Answer 7

Heat cured PMMA

• Adding more of the same material used for denture
• Lab cured - expensive, more accurate, good for big alterations
• Trim down 2mm around entire periphery and in undercuts so make room for new liner
• ZOE impression - ask pt to bite down on opposing denture to compress material and height of denture doesn’t change too much
• Silicone impression - hydrophobic so need to use heavy body

Question 8

Permanent liners - Autopolymerising PMMA?

Answer 8

Chairside cured - not fully polymerised, cheaper, small corrections

• Overtime become stained due to slight porosity
• Plasticised, autopolymerising, PMMA
• Dispensed as powder/liquid, good handling properties, quick set
• Bead on distal margin of denture - allow to set in mouth, ideal for addition of functional post dam

Question 9

Indications for hard liners - PMMA?

Answer 9

Relining dentures
Additions to dentures
Placement of post dams

Question 10

Indications for soft liners?

Answer 10

Relining dentures
Tender Md ridge
Over mental foramen
Need to be at least 4mm thick

Question 11

Features of temporary liners?

Temporary liners composition?

Answer 11

On for 2 weeks max
Soft liners
Functional impression materials
Tissue conditioners

Composition

• Usually PEMA
• Dibutyl phthalate
• Ethyl alcohol
• Benzyl salicylate

Question 12

Indications for temporary liners?

Answer 12

Immediate dentures
Pain relief e.g. after XLA on healing socket
Conditioning of tissues
Functional impression materials

Question 13

How to manage a sharp bony ridge after XLA?

Answer 13

Cushing effect of liner reduces discomfort

Question 14

What can result in pain/paralysis/parasthesia?

Answer 14

Excessive bone atrophy a long time after XLA - mental nerve orifice exposed