Metal allow of which one of the elements is mercury (Hg)
Amalgam
Metals that are a combination of several elements
Alloys
_____ ______ is made by mixing approximately equal parts (by weight) of a powdered metal alloy with liquid mercury
Dental amalgam
The mixing process of the alloy with the liquid mercury is called
amalgamation or trituration
The mechanical device is called
amalgamator or triturator
What is the working time of the amalgam?
the time needed to condense and carve
First method used to produce dental amalgam particles is grinding an ingot of metal to produce filings. Such amalgam alloys are called
lathe-cut alloys
Second method used to produce dental amalgam particles is to spray molten metal into an inert atmosphere. The droplets cool as they fall, producing
spherical alloys
Soem products are a combination of both lathe-cut alloys and spherical particles called
admixed or blended alloys
Amalgam alloy is the
silver-tin
When was dental amalgam developed?
France in the 1800s
Process in which a solid is formed from a material dissolved in a liquid
Precipitation
Microstructure of Low-Copper Amalgams
y (Ag-Sn)
y1 (Ag-Hg)
y2 (Sn-Hg)
**Etan Sn-Cu-Hg replaces y2
A slow change in shape caused by compression
Creep
Resin dissolved in a solvent
Copal varnish
What is an effect of moisture?
delayed expansion
What type of restorations require extreme attention to detail and considerable skill?
Gold foil, also called direct gold or cohesive gold
Which of the following elements is used in the highest amount in an amalgam restoration?
a. tin
b. copper
c. silver
d. mercury
e. aluminum
d. mercury
Amalgam is strongest in _______ strength after it has set
a. shear
b. tensile
c. compressive
d. bending
c. compressive
The elements composing the gamma-two (y2) phase (the weakest and most corrosion-prone phase) of amalgam reaction are
a. silver and tin
b. silver and mercury
c. tin and mercury
d. tin and tin
c. tin and mercury
The function of silver in the amalgam reaction is to:
a. reduce strength and corrosion resistance
b. increase strength and corrosion resistance
c. minimize oxidation
d. maximize oxidation
b. increase strength corrosion resistance
control of the mercury content during mixing and condensing of amalgam must be carefully considered because
a. the higher the mercury content, the higher the strength and the lower the marginal breakdown
b. the lower the mercury content, the higher the st
b. the lower the mercury content, the higher the strength and the lower the marginal breakdown
The single most important feature that accounts for the clinical success of amalgam restorations is
a. finish and polish
b. marginal seal
c. economy
d. ease of manipulation
b. marginal seal
The manufacturers of dental amalgam control all of the following except
a. alloy composition
b. rate of setting reaction
c. proper trituration technique
d. particle size
c. proper trituration technique
An amalgam restoration that has been finished and polished
. reduces the ability of plaque to adhere
b. resists tarnish and corrosion
c. will not have any voids
d. is more likely to have continuous margins with tooth structure
e. all of the above
f. a, b,
f) a, b, and d
In the low-copper or traditional amalgam reaction, tin reacts with mercury. In the high-copper amalgam reactions, tin reacts with
a. silver
b. copper
c. zinc
d. mercury
b. copper
The life expectancy of an amalgam restoration is indirectly related to the size of the restoration. As the restoration increases in size, internal stresses decrease, as does the life expectancy True or False
First statement true, second statement false
Ashley was condensing an amalgam during lab and she noticed that the triturated amalgam had a softer, "mushy" feel. What type of alloy did she most likely use in the mixed amalgam?
a. spherical
b. lathe-cut
c. admixed
d blended
a. spherical
Just as Jennifer triturated her amalgam, the appearance of it was "crumbly" and dry. it already looked set. The amalgam was most likely
a. mixed with an increased mercury/alloy ratio
b. over triturated
c. properly triturated
d. under triturated
b. over triturated
Amalgam may be used for a variety of restorative procedures. ALL of the following pertain to the use of amalgam EXCEPT
a. Good service to patients at a reasonable cost
b. for cingulum pit areas on the lingual of anterior teeth
c. amalgam cores
d. restorin
d. restoring Class I, II, IV, and V caries
It has been reported in the scientific literature that _____% of dental patients have a TRUE mercury allergy
a. 0.01
b. 0.05
c. 0.1
d. 1.0
c. 0.1
The use of gold foil is limited to small restorations because of its
a. short term longevity
b. low strength compared to other restorative materials
c. high cost of gold foil compared to other materials
d. unique handling characteristics
b. low strength compared to other restorative materials