DMS- Acrylic resin

Question 1

What is transverse strength?

Answer 1

How well the denture copes with stresses that cause deflection.

Question 2

Compare heat cured acrylic dentures to self curing dentures?

Answer 2

We chose a heat cured acrylic denture.

It becomes undersized as it contracts by 0.5mm during manufacture and expands by 0.4mm due to uptake of water during use. There is 0.1-0.5% unreacted monomer.

A self curing denture- the tertiary amine activates the benzoyl peroxide. This is less efficient leaving 3-5% leftover unreacted monomer.

This causes the denture to be oversized as there is exansion due to water uptake but less contraction.

Question 3

Discuss the use of Ultra-Hi as a denture base product?

Answer 3

This is used in the GDH as it has a greater deal of ductility (mitigating any cracks) and has greater flexural strength (so will survive longer)

Question 4

What is a light activated denture resin and when is it used?

Answer 4

This material is made of:

• Acrylic co-polymer
• Photoinitiator
• Urethane dimethacrylate matrix
• Acrylic copolymers.

These are used for customised impression trays and the repair of fractured dentures.

Question 5

Why do we not use radiopaque polymers?

Answer 5

Because it made the material too weak.

Question 6

What alternatives can the patient use if they have an allergy. Compare them.

Answer 6

Nylon (Disadvantage- it absorbs water causing swelling and softening)

Vinyl polymers (soften at 60*c and require an expensive technique to mould)

Polycarbonates (can withstand high temperatures but distort when in use causing a poor fit)