amalgam
an alloy ( a mixture of 2 or more metals, binary or tertiary) 1 Hg, the only metal thats liquid at room temp
dental amalgam
Hg combined with power of Ag, Sn, aCu, and Zn
Amalgamation/ trituration
process of mixing
amalgamator/Triturator
the mixer
components of dental amalgam
capsule, pestle, alloy powder
lathe cut alloys & spherical alloys
2 types of alloy shapes
tough, wear resistant, long lasting, cost effective, seals margins
advantages of using dental amalgam
Mercury
what liquid needs to be added to an alloy to produce a dental amalgam
seal margins
what can we do with amalgam to decrease micro leakage
France
amalgam was first developed in
low copper
Ag increases strength and corrosion resistance, Zn acts as deoxidizer, Sn is weak link
Dispersealloy
first high copper dental amalgam admix
high copper dental amalgam
admix, spherical, setting reactions displace tin which is weak link
gamma (y)
silver/ tin component, strongest, most corrosion resistant
higher cost
more silver =
Lathe cut or admix
when restoring class II restoration (has to break the contact) we need to have what type of amalgam
spherical
which type of amalgam is too weak for a class II restoration
creep
the gradual flow of a material under stress
low creep values
good
corrosion of dental amalgam
can lead to failure
tarnish
surface discoloration
what type of environment do we see corrosion
acidic environments
delayed expansion
what happens when too much moisture contaminates the amalgam
class II
require a matrix band and a retainer
secondary decay, marginal breakdown, cusp fracture
amalgam failure is likely due to
I's and V's
gold restorations were formally seen in small class
isolation & dry field
purpose of rubber dams
stamp the material
1st step in preparing the rubber dam material
punch the holes
2nd step in prepping the rubber dam material
prepare the clamp
2rd step in preparing the rubber dam material
posterior
bow of clamp always faces the
anterior
butterfly clamps are used on which teeth