DMS 3

Question 1

4 stages in acrylic resin polymerisation

Answer 1

1 - activation - of initiator to produce free radicals
2 - initiation - free radicals break C=C bonds in monomers and transfer free radicals
3 - propagation - growing polymer chain
4 - termination - of polymerisation

Question 2

initiator within PMMA

Answer 2

benzoyl peroxide

Question 3

gaseous porosity

Answer 3

may be seen in PMMA if heat cured too fast

Question 4

contraction porosity

Answer 4

may be seen in PMMA if insufficiently packed during curing process

Question 5

ISO standard for impression materials
(depth of replication)

Answer 5

grooves/indentations of 20 or 50 micrometres

Question 6

ISO

Answer 6

international orginisation for standardisation