Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DCP2 > Dental amalgam > Flashcards

Dental amalgam Flashcards

1
Q

what is dental amalgam

A

an alloy of mercury mixed with metallic elements including silver, tin, copper, palladium, indium, and sometimes zinc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the purpose of dental amalgam in restoration

A

dental amalgam is used to create plastic mix that is applied to prepared cavity to restore the teeth structure and function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the role of mercury in amalgam

A

mercury liquefies and reacts with amalgam alloy to produce plastic mix that remains workable at room and body temp for reasonable period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

improper handling of mercury can cause what

A
  • systemic absorption through skin
    -inhalation of mercury vapor
    -inhalation of air borne particles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are some mercury hygiene procedures in dental office

A
  • avoid baseboard heaters
    -avoid carpeting
    -ensure proper ventilation
    -regular monitoring of Hg vapor levels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are mercury hygiene practices for dental personnel

A

-no touch technique when handling mercury
-wear a face mask
-regular urine analysis
-wear detection badages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are important mercury hygiene techniques

A
  • -regularly check amalgamator
  • when removing old amalgam use water spray and suction
  • store Hg in cool place
  • store amalgam scrap in capped jars containing water with x-ray fixer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the affects of silver in dental amalgam alloy

A

increases : strength , resistance, to tarnish and corrosion and setting expansion

decreases : flow and creep, setting time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are affects of tin in dental amalgam alloy

A

increases: flow and creep and setting time

decreases: setting expansion , strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are affects of zinc dental amalgam alloy

A

increases: strength, plasticity of mix
delays: expansion when contaminated with saliva
prevents oxidation of alloy constituents during manufacturing
decreases rate of marginal fracture under occlusal load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the types of dental amalgam alloy based on copper content

A
  • low copper amalgam alloy ( convectional amalgam alloy): contains 2-5% copper
  • high copper amalgam ( non gamma 2 amalgam alloy): contains 13-30% copper
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the types of dental amalgam alloy based on zinc content

A

-zinc containing amalgam alloy
- zinc free amalgam alloy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how is the lathe cut prepared

A

by grinding an ingot of alloy on lathe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the characteristics of lathe

A

-particles are small they range from several micrometer to 200 micrometer in diameter

-irregular shape with sharp edges and rough surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how is spherical alloy prepared

A

the ingot of alloy is melted and then sprayed through a nozzle
method of preparing known as water atomization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are characteristics of spherical alloy

A
  • particles have smooth surfaces and margins with a diameter of several micrometer to 100 micrometer
17
Q

what is admired alloy

A

oldest type of high copper alloy

18
Q

what is admired alloy composition

A

mixture of 2 alloys
1- high copper spherical particles( copper 20-40%)
2- low copper lathe cut particles

19
Q

what is the total copper content of admired alloy

A

9-20%

20
Q

what are the type of alloy particles based on size

A

micro cut
fine cut
coarse cut

21
Q

what happens during setting reaction of low copper amalgam

A

tin reacts with mercury compound (y2)
reaction: silver tin y2 + mercury give us AgSn+ AgHg+ SnHg

22
Q

y or y1 or y2 is the weakest phase and low strength phase of amalgam

A

y2

23
Q

what is the weakness of low copper and amalgam

A

low strength: y is more than y1and y1 is more than y2
low corrosion resistance : y1 is more than y and y is more than y2
high creep
low marginal integrity
lowest melting point of all phases in set amalgam

24
Q

what happens during setting reaction of high copper amalgam

A

Tin reacts with copper to form tin copper compounds( non y2 phase)
reaction: silver tin y + copper + mercury will give us AgSn y+ AgHg y1 + CuSn

25
Q

in high copper amalgam reaction we don’t have y2 what does that mean

A

it leads to stronger and more resistant corrosion amalgam and high copper has 13% to 30% copper

26
Q

what is the range of mercury content in dental amalgam and what factors influence it

A

the mercury content in dental amalgam is 40-50% influenced by shape , size and composition of alloy particles

27
Q

why do irregular alloy particles require more mercury in amalgam

A

to fill spaces between them cuz of their uneven shape which create more voids that need to be filled

28
Q

how does using spherical alloy particles affect mercury content in amalgam mixture

A

reduce the mercury portion to less than 50% cuz they fit together more efficiently leaving fewer gaps to be filled

29
Q

which of these require more mercury due to their particles less efficient packing
A- high copper spherical alloys and mercury
B- low copper microfine lathecut alloys

A

B- low copper microfine lathecut alloys

30
Q

the final mercury content in amalgam is influenced by

A

by the initial mercury content and clinical technique used during placement specially the force of condensation applied

31
Q

how does condensation technique affect mercury in amalgam

A

it packs the core particles closer together and drives excess mercury to surface n that reduces the amount of mercury within amalgam mass

32
Q

what happens if excess mercury is retained in amalgam matrix

A

can lead to loss of physical properties such as strength and durability making restoration less effective

33
Q

what issues arise from a lack of dispensed mercury or faulty trituration

A

can create weak particle/ matrix interface which results in reduction of amalgam physical properties compromising its integrity

34
Q

define corrosion in amalgam restoration

A

electrochemical destruction of metal by reacting with environment

35
Q

types of corrosion

A

tarnish or surface corrosion
stress corrosion
galvanic corrosion

DCP2 (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions