Module 3 Flashcards
What is the only pure metal that is liquid at room temperature?
Mercury
What is an alloy?
mixture of 2 metallic substances
Amalgams are classified according to?
composition (low/high copper)
particle size
What is Amalgam made of?
Mercury Silver Tin Copper Zinc (sometimes)
One problem with the ZINC in amalgam is?
uncontrolled enlargement of amalgam (creep)
One advantage of ZINC?
adds plasticity (eases condensing)
The majority of alloys are _____ copper content?
high
Copper increases the ______, _____, ______ expansion, and _________ resistance?
strength
hardness
setting
corrosion
Low Copper content leads to?
corrosion
We want a Gamma __ reaction?
1
A Gamma 2 reaction is between ___ and Mercury?
tin
A Gamma 1 reaction is between _____ and mercury
silver
Percentages of Copper in Low VS High copper amalgams?
4-5% = low 13-30% = high
What are the 3 types of particle sizes in amalgam?
Lathe
Spherical
Admixed
What is the benefit of Spherical amalgam particles?
can be packed closely together
What are 4 advantages to using amalgam restorations?
easy to insert
not technique sensitive
resists fracture
long service life
Corrosion of amalgam is decreased when it is?
polished
Kaolin in the Ceramic material becomes _____ when wet?
cohesive
Fledspar particle in ceramics fuse and form glass of the same shape when subjected to?
high heat
What is the difference between Porelain and Ceramic?
Porcelain is fired (baked)
Ceramic is cast (machine milled)
What are 2 disadvantages of ceramic/porcelain restorations?
cause wear on opposing enamel
affected by APR (acids containing fluorine)
What is the difference between an inlay/onlay?
inlay lays “within” the cusps
only lays “on” cusps
Metal reactivity has an _______ relationship?
inverse
If a metal has LOW reactivity it has _____ nobility
HIGH