restorative and aesthetic material ch 43 Flashcards
amalgam =
name given to “silver things”
consists of many different metals with silver being the predominant metal. Mixed with approx, equal parts of mercury
dental amalgam
contraindications to dental amalgam
asthetics are important
pt has a history of allergy to mercury
cost
alloy powder mixed with mercury
forms a soft pliable mixture
when placed in a tooth, condensed, carved, and allowed to harden, the mixture become a permanent
dental amalgam
silver
65% gives amalgam its strength and silver color
tin
29% for its workability and strength
copper
6% for its strength and corrosion resistance ability
zinc
2%, to suppress oxidation
—-+—– = amalgam
alloy + mercury
physical characteristics of mercury
liquid at room temp
vaporizes with increased heat
highly poisonous
where to store scrap amalgam
in a wide mouth airtight container marked
non-contact amalgam
amalgam handling
do not contact skin
protect against spillage during mixing
do not throw away in general waste
advantages of amalgam
best restorative material for posterior teeth
user friendly can be mixed, placed, and carved in a short time
can last very long
disadvantages of amalgam
non-esthetic in color
contains mercury so its dangerous
takes 24 hrs to completely set
capsules (600 mg of alloy)
for small or single surface restorations
capsules (800 mg of alloy)
for larger restorations
trituration
process by which the mercury and alloy powders are mixed together to form the mass of amalgam
what is mixing done by
an amalgamator
Etch can be supplied as
liquid/gel
malice acid
phosphoric acid
what removes the smear layer
acid etching
when you apply etch to enamel how long do you leave it for
ranges from 15-30 secs
T/F; avoid contact with soft tissue, rinse thoroughly if contaminated with acid etch .. Protect pulp
True
Bonding agents function
reduce microleakage, reduce sensitivity , help living tissue inside tooth recover from stress
when to place bonding agents
placed in tooth after cavity prep and just before placement or restorative material