pure gold=___% and ____% = _____ fine and _____ fine=___ karate
how many karates is 500 fine or 50% gold?
what are the classifications for casting alloys? 3
high noble metal
t/f noble metals have no gold requirement
what are three examples of noble metals?
what is the most corrosive resistant nobal metal?
what % of gold is 14K?
if 24K is 100% and 12K is 50% (12/24=.5...hence 50%) SOOOO 14/24=.5833333333333333 and there you have it!
_____ is a dental alloy that is not used much
what noble metal is a good corrosive resistance, increases hardness of alloy and is less expensive than gold
palladium dental alloy is _____ corrosive resistance, ______ hardness of alloy and _____ expensive than gold
why is silver not a noble metal?
because of high tarnish and corrosion
what base metal is the highest incidence of allergic response
how is a nickel allergy shown?
blackness around gumline
what reduces the oxidation of alloy during casting of a base metal?
what is added to gold to incrase hardness?
copper and silver
why is zinc added to gold?
to reduce oxidation of cast alloy
what is added to gold based alloys to keep crystals from growing too large?
iridium or ruthenium
what is added to form oxides on the metal to bond porcelain? 4
indium, iron, gallium and tin
the substructre of porcelain is heated at high temperatures to form what on the surface?
how does the porcelain fuse to the oxide layer
how thick is coping metal?
how much does the tooth have to be reduced for a PFM?
what is responsible for allergic responses?
what has the highest incidence of allergenicity?
who is more likely to have a nickel allergy?
WOMEN 10:1 over men
why are women more likely to be allergic to nickel?
jewelry (topically applied-worst kind of allergy)
where in the mouth is the most common site for nickel allergy?
corwns around free gingival tissues
t/f some responses to nickel in the mouth cause skin reaction
_____ fineness number of gold solder, the _____ the gold content the _____ the melting point of the solder
what is added to both gold and silver solders to lower the melting range?
solders can be gold or silver what is an example of a silver solder?
ortho fixed space maintainer
solder wire components together
t/f wrought metal alloys may be annealed (what does that mean)
what is an example of a wrought wire?
clasps for removable prothesis
arch wire held to ortho bracket by ____ wire or ____
what is held to the ortho bracket by ligature wire or elastics?
t/f reamers have more twists than files
what cuts faster reamers or files?
what is the canal sealed with so bacteria can't grow in the space
what is gutta percha used for?
to seal the canal so bacteria cannot grow in the space
what is the purpose of a endodontic post?
retain core buildup
t/f the endo post is in the canal perpendicular
why is the endo post parallel?
to transmist less stress to the root than tapered
casting metals, solders, and wrought metal alloys