what alloy is used to fabricate inlays, onlays, crowns, and bridges?
casting alloys
what is the most widely used material in restorative dentistry?
metal
metals have ____ strength, can melt at_____ temp, ______ temp and electricity, and can be polished to a high _____ (luster)
high
high
conduct
shine
t/f metals have varying degrees of ductility
true! they can be pulled or drawn into a wire
t/f gold is ductile and the margins of gold restorations can be burnished for a better adaptation to tooth preparation margins
true
in the 1900s, who developed a technique for making dental restorations from metal that was melted and cast into a mold? what was this technique called?
Taggart
lost wax technique (used dental casting alloys use this technique)
t/f alloys unlike amalgam are placed directly into the preparations, and inside the mouth
false! OUTSIDE the mouth
which metals are seldom used in dentistry?
pure metals
intracoronal preparations are _____ the tooth
inside
extracoronal preparations are _____ the tooth
outside
______ is both intra and extracoronal
onlay
which cast metal restoration is 100% inside the tooth, and has no undercuts?
INLAY
which cast metal restoration is an inlay and includes one or more cusps?
ONLAY
which two types of crowns are extracoronal?
full coverage
partial coverage
what is inside the tooth PLUS covers one or more cusps? Which restoration?
ONLAY
which type of casting alloy for restorations may be intracoronal or extracoronal? (hint: pure or cast?)
cast-metal restoration
high noble metal = at least ___% noble metal weight and ____% gold weight
60%
40%
t/f an inlay restoration can also cover the outer surface of one or more cusps
true
which alloys do not require any gold but contain at LEAST 25% noble metals by weight?
noble alloys
which alloys do not require gold and require LESS than 25% of noble metal weight?
base-metal alloys
what is the most corrosion resistant of the noble metals that has been used in dentistry for centuries?
GOLD!
Au = _______
GOLD!
Pt = _______
Platinum
Pd =________
Palladium
what are the three noble metals in RED?
gold
platinum
palladium
t/f silver is a noble metal and a precious metal
FALSE! only a precious metal!
why is silver not a noble metal?
because of high tarnish and corrosion
which is the most corrosive resistant noble metal?
gold
pure gold = ___ carat which is ____% or _____ fine
24
100%
1000
half of pure gold = ____K = _____% and ______ fine
12 K
50%
500 fine
gold is classified by what three things?
hardness (resistance)
malleability (shaped)
ductibilty (stretched)
which noble metal in RED is not used much in dentistry?
platinum (expensive, high melting point, and difficulty mixing with gold)
which dental alloy has GOOD corrosive resistance INCREASES hardness of alloy and is LESS expensive than gold?
Palladium
the more ductile the alloy, the ____ the margins can be burnished
more
platinum and palladium are also known as ______ metals because of their high monetary value
precious
Cu =______
Ni =______
Ag =______
Zn =______
Sn=______
Ti=______
these are all _____ metal alloys
copper Cu
Nickel Ni
Silver Ag
Zinc Zn
Tin Sn
Titanium Ti
BASE metal alloys
base metal alloys are ___ _____ metals
non precious (due to lower cost)
base metal alloys have less than ___% noble metal
25%
do noble class alloys require gold?
what percentage of noble class metals is base metals?
no
75%
what metal has the highest incidence of allergic response?
Nickel
what will happen if someone is allergic to nickel?
a black line around the gumline will appear
what base metal increases harness of gold alloys?
copper
what reduces oxidation of alloy during casting? which base metal?
