Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

2ND Year - CSA clinical aspects > Amalgam > Flashcards

Amalgam Flashcards

1
Q

Define amalgam

A

Any alloy of mercury with another metal other metals

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

Defne dental amalgam

A

Essentially an alloy of silver =, mercury and tin with some other metals aded to modify the properties

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

State the chemical reaction that forms amalgam

A

Ag + Sn=> Ag3Sn

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

What shapes can the alloy powder particles be in?

A

Lathe cut

Spherical

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

What is amalgam made up f?

A

Amalgam powder (made up of silver , copper etc)
AND
liquid mercury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Let the 3 possible reagins the can occur when liquid mercury and amalgam powder are mixed together?

A
  1. 3Ag+Sn=>Ag3Sn
  2. 2Ag+3Hg=>Ag2Hg3
  3. Hg+7Sn=>Sn7Hg
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

State the gamma reaction that occurs when liquid mercury and amalgam powder are mixed together

A

3Ag + Sn => Ag3Sn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

State the gamma 1 reaction that occurs when liquid mercury and amalgam powder are mixed together

A

2Ag + 3Hg => Ag2Hg3

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

State the gamma 2 reaction that occurs when liquid mercury and amalgam powder are mixed together

A

Hg + 7Sn => Sn7Hg

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

Which of the 3 reactions that occur in amalgam the most problematic?

A

The gamma 2 reaction :

Sn7Hg

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

What is the gamma 2 reaction responsible for?

A
  1. Corrosion
    2, Creep
  2. Decrease in strength
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do we ad to amalgam to reduce the gamma 2 phase?

A

Copper

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

State the gamma 2 reaction when copper I added

A

AgCu + Sn7Hg => Cu6Sn5 + Ag2Hg3

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

Name the 4main ingredients that makeup modern amalgam powder

A
  1. SIlver
    2, Tin
  2. Copper
  3. Zinc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

State the percentage weight of silver in modern amalgam powder

A

65%

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

State the percentage weight of tin in modern amalgam powder

A

29%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

State the percentage weight of copper in modern amalgam powder

A

6-13%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

State the percentage weight of zinc in modern amalgam powder

A

2%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the IDEAL ratio of powder to liquid in amalgam

A

Ideally final amalgam restoration should contain less than 50% mercury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the problem with trying to mix powder with less than 50% mercury?

A

It is very difficult as the mixture is too dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do we overcome the problem of too dry amalgam mix?

A

By increasing the amount of mercury BUT then later removing in when we are packing

22
Q

How do we remove the excess mercury the setting our amalgam filling?

A

During packing the excess mercury indrawn to the top and hen we scrape it away during carving

23
Q

Describe spherical amalgam powder particles

A

They are softer and more flowable

24
Q

Describe lathe cut amalgam powder particles

A

Less flowable

Good for building up late amounts missing tooth structure

25
Give some advantages of amalgam
1. Has good compressive strength 2. Good wear resistance 3. Kind to opposing teeth 4. Easy to use 5. chemically set 6. Cheap 7. Radio-opaque so can be seen on radiographs
26
What are the disadvantages of amalgam
1. It is non-adhesive 2. It's weak in thin sections 3. It's a thermal conductor 4 It's Unaesthetic 5. Can become a plaque retentive factor
27
Give some properties of amalgam
1. Non adhesive 2. Weak in thin sections 3. Thermal conduction / expansion 4. Corrosive 5. Unaesthetic 6 Reactions (lichenoid reactions)
28
When would we place an amalgam filling?
1. Class I and class II caries 2. Areas where heavy occlusal forces are encountered 3. Where aesthetics are not important 4. Building up broken teeth prior to crowning
29
What qualities must our cavity have before we place an amalgam filling
1. Clean walls 2. No unsupported enamel prisms 3. Undercut 4. Cavosurface angle greater than 90 5. Amalgam-margin angle greater than 70 6. Cavity must be greater than 2mm
30
What is an undercut ?
When the base of the cavity wider than the top
31
What is retention?
The prevention of the amalgam filling from being puled out vertically
32
What type of retention is displayed in amalgam?
Retention is macro molecular
33
When may an undercut not be sufficient ?
When a cusp of the tooth is completely missing
34
What do we NOT use anymore to keep amalgam in place if a cusp is missing?
Pins
35
Why do we no longer use coins when placing an amalgam restoration?
The pins can: Go into the pulp Weaken the tooth
36
What do we do instead of placing pins?
Create pits and grooves
37
Does phishing improve the life expectancy of amalgam restorations?
NO
38
What is the problem with polishing amalgam?
Amalgam takes 24 hrs to set so you can't polish straight away Also polishing generates heat which may irritate the pulp
39
Compare he median age of replacement of amalgam with composite
``` Amalgam = 15 yrs Composite = 8 yrs ```
40
Compare the average life span of amalgam and composite
``` Amalgam = 12 yrs Composite = 5 yrs ```
41
What is the main reason for failure for both amalgam and composite?
Secondary caries
42
Does amalgam or composite have a greater risk of developing secondary caries
Risk of secondary caries was 3.5 times greater in composite than amalgam
43
Does amalgam perform better in large or small restorations?
Large
44
How much of amalgam is made up of mercury|
Approx 50%
45
What state of mercury is toxic?
Mercury vapours is highly toxic
46
When are mercury vapours released in dentistry?
Mercury vapours are released from amalgam fillings during chewing and toothbrushing
47
What has amalgam been blamed for?
1. Neurotoxicity 2. Kidney disfunction 3. Reduced immunocompetence 4. Birth defects 5. Effects on oral & intestinal bacteria
48
What has reared shown on the effect f amalgam on our health?
It has never been convincingly show that the negligible levels of mercury entering the body from amalgam fillings have any impact on general health
49
What is the main reason mercury is being phased out?
Due to its detrimental affect on the environment
50
What happens when mercury enters the environment?
It s converted by bacteria into Methy mercury in fresh and salt water
51
Why is methyl mercury dangerous?
It is highly poisonous
52
How do we dispose of amalgam in the clinical skills labs?
Put empty capsules and waste amalgam in the receptacles provided ◦ Clean the heads into the designated sink (This has a separator on it) Report any spillages

2ND Year - CSA clinical aspects (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions