Tutorial 10a - Properties + choices of materials relevant to RPD constructions Flashcards

Question

DENTURE CLASP MATERIALS What does the amount of retention depend om?

Answer 1

A

accurate - good fine detail
can be used with undercuts - accurately reproduces shape without distortion
easy to use/ handle
cheap + affordable
good shelf like
flows better + less viscous than silicone putty
non- toxic/ irritant + acceptable taste/ smell
compatible with stone/ plaster
good hydrophilic properties

Answer 2

A

need to retake if incorrect
blow holes can occur - due to incorporating too much air
tears easily (hard with V deep undercuts
mixing important - temp, humidity, etc affect composition of materials, qualities, working + setting time
cannot be recast
lack of dimensional stability = can swell due to water absorption or shrink due to water evaporation so needs to be cast quickly and kept moist
(- distortion due to syneresis or imbibition - needs to be cast immediately)

Answer 3

A

condensation
- mainly used in lab
- alcohol by-product during
polymerisation causes instability
- 2 phase usu hand mix
addition

Answer 4

A

ADVANTAGES
- cheap
- good elastic recovery
- good detail
- good working time
- pleasant taste/ smell

DISADVANTAGES
- low tear strength
- volatile by-product
- poor dimensional stability
- short shelf life
- hydrophobic

Answer 5

A

diff viscosities available: ultra light, light, medium, heavy + putty
accurate - with use of different viscosities
good tear resistance
dimensionally stable - can be cast some time after not immediately
non toxic/ irritant, pleasant smell/ taste
can be recast multiple times
good shelf life
good working/ setting time
automix available (easier to mix + dispense)
accurate in recording landmarks
high resistance to deformation
high elasticity

Answer 6

A

expensive compared to alginate
not common but can lock into deep undercuts
(add notes on cheung’s sheet, cannot read)
can’t use with latex gloves (sulphur contamination impedes setting)
hydrophobic - surfactants added to make more hydrophilic BUT can then suffer from imbibition
can be V rigid = be aware of mobile teeth
more difficult to remove from mould
longer setting time than alginate
sensitive to contaminates

Answer 7

A

palate
large edentulous saddles where teeth are missing
distal extension saddles

Answer 8

A

1
1. acrylic
2. cobalt chromium (CoCr)
3. thermoplastic - flexible nylon
(add notes on cheung’s sheet, cannot read)

2
1. Type IV gold alloy
2. Titanium
3. Stainless steel
- can be V thin + light, fracture resistant,
corrosion resistant + good thermal
conductivity
4. aluminum
- accurate

Answer 9

A

Type IV gold alloy
- V expensive + outdated

titanium
- lightweight + biocompatible BUT expensive + complicated casting

Answer 10

A

adequate physical + mechanical properties

Answer 11

A

1
- Polymethylmethacrylate (PMMA)

2
- can be heat cured or self cured

3
self cured = has 80% strength of heat cured + more residual monomer

Answer 12

A

cheap
good for long span edentulous areas
easy to reline - for transitional cases
easily adjustable + can add teeth to it if poor prognosis in arch
biocompatible
mainly mucosal support but can add clasps for extra retention (gold/ stainless steel)
asthethetic (potentially no clasps required)

Answer 13

A

Polyamide nylon = single polymeric chain)

EGs

valplast
flexite
TCS
Iflex
Duralex

Answer 14

A

(Make more detailed Q???)