Dental Amalgam

Question 1

What is dental amalgam the product of?

Answer 1

amalgamation

Question 2

define amalgamation

Answer 2

mixing of alloy with mercury

Question 3

what 5 metals make up dental amalgam?

Answer 3

silver, tin, zinc, mercury and copper

Question 4

name the 2 compositions of dental amalgam

Answer 4

conventional

higher copper

Question 5

give the 2 variations in alloy morphology for dental amalgam

Answer 5

lathe cut

spherical

Question 6

what effect does copper have on dental amalgam?

Answer 6

strengthening effect

Question 7

what does zinc act as in dental amalgam?

Answer 7

as a scavenger for oxygen to prevent oxidisation of the other metals

Question 8

what must the clinician do to the amalgam before using it on patient?

Answer 8

triturate (mix) it

Question 9

placement to function of amalgam restoration?

Answer 9

15-20 minutes

Question 10

final strength of restoration?

Answer 10

24 hours

Question 11

give the term for:

plastic deformation of amalgam under load that presents as protrusions at restoration margins

Answer 11

creep

Question 12

what is ‘creep’ exacerbated by and why?

Answer 12

CORROSION causes release of Hg in the merging crevice and localised expansion of amalgam occurs

Question 13

what is the positive aspect of corrosion of dental amalgam?

Answer 13

corrosion products provide marginal seal

Question 14

what increases the chances of corrosion of dental amalgam?

Answer 14

contact with gold restoration

Question 15

what does packing and condensation remove when placing an amalgam restoration?

Answer 15

excess mercury

Question 16

what does small particle size of alloy in dental amalgam achieve?

Answer 16

higher initial and final strength

Question 17

describe the dimensional changes in amalgam over time after trituration

Answer 17

small shrinkage during first 30 mins

expansion due to crystallisation in next 30-60 mins