Amalgam Flashcards
When would you not want to use amalgam?
Aesthetics are important
Patient has a history of sensitivity to mercury or amalgam.
Retentive cavity cannot be produced due to loss of tooth substance.
Where excessive removal of sound tooth substance would be required to produce a retentive cavity.
When might you consider using amalgam?
Large posterior cavity.
Inadequate moisture control.
Aesthetics not important
Patient cannot afford composite.
Name some advantages of amalgam.
Durable
Long lasting
Shorter placement time
Less clinically demanding for the operator
Corrosion products may seal the tooth restoration interface.
Economical
Good compressive strength.
Good abrasion resistance.
Name some disadvantages of amalgam.
Poor aesthetics.
Maintained in place with retentive and resistance form, so need to remove sound tooth tissue to do so.
Does not bond directly to tooth.
Corrosion at tooth-restoration interface may result in ditching.
Local sensitivity reactions.
Tooth discolouration- corrosion products migrate into tooth surfaces.
Exposed to creep.
For amalgam- what is consider sufficient depth of the cavity?
1.5-2mm.
For amalgam- the gingival floor of an inter proximal box should be approximately how far to the axial wall?
90 degrees.
Is moisture contamination ok for amalgam?
A degree of moisture contamination is okay but it is better to keep the cavity dry.
What occurs if you have moisture contamination with amalgam?
Reduces strength
Increases creep
Increases corrosion
Increases porosity
Why is condensation important during amalgam application?
Expels excess mercury bringing it to the surface where it will be carved off.
Eliminates voids.
Adapts the material to the cavity walls.
For amalgam- what is the correct cavosurface margin angle?
90 degrees.
What is the Cavo surface margin angle?
Junction of prepared tooth to unprepared tooth.
How would you remove an amalgam restoration?
Under dental dam, with high volume aspiration.
High speed to chunk the amalgam and remove it this way.
How much mercury is absorbed from a filling?
0.5 micrograms/surface/day.
Equates to 490 amalgam surfaces would be required to reach the exposure dose limit.
When should you never place an amalgam?
Children under 15
Pregnant women
Breastfeeding women
A patient wants you to remove their amalgam restoration and replace with composite. What is the justification?
No justification on health grounds for not placing amalgam restoration.
No justification for removal of sound amalgam restorations unless there is a proven allergic reaction.
