2. restorations that have heavy occlusal - 3 •
contacts
restorations that cannot be well isolated- 4 •
restorations that extend onto the root - 5 •
surface
foundation- 6 •
abutment teeth for a removable partial - 7 •
denture
temporary or caries control restoration- 8 •
3. ;Contraindications •
Amalgam has no specific •
contraindications for use in class I ,II,VI
;Amalgam may be contraindicated in •
esthetically prominent areas of posterior - 1 •
teeth
small to moderate classes I &II that can - 2 •
be well isolated
small class VI restoration- 3 •
4. Advantages of Amalgam Restoration •
Ease of use- 1 •
high strength- 2 •
excellent wear resistance- 3 •
lower cost- 4 •
5. ; Disadvantages •
non esthetic- 1 •
less conservative- 2 •
weakens tooth structure- 3 •
more difficult tooth preparation- 4 •
initial marginal leakage- 5 •
6. Common Problems Associated with •
amalgam restoration
Causes and potential solutions •
Postoperative sensitivity- 1 •
Causes •
a- lack of adequate condensation •
b- lack of proper dentinal sealing with •
liners
8. MARGINAL VOIDS- 2 •
;Causes •
a- inadequate condensation •
b- material pulling a way or breaking the •
marginal area
POTENTIAL SOLUTION •
a- proper condensation •
b- careful carving of marginal areas •
9. MARGINAL RIDGE FRACTURE- 3 •
: CAUSES •
a- axiopulpal line angle not rounded •
b- marginal ridge left too high •
c- improper removal of matrix •
d- overzealous carving •
10. POTENTIAL SOLUTION •
a- proper rounding of axiopulpal line angle •
b-creating marginal ridge height correctly •
with the adjacent tooth & occlusion
c- removing matrix correctly •
11. ;Basic components of amlgam •
Silver ( Ag) 40-70%- 1 •
;The silver will affect the following •
a- decrease the setting time •
b- increases the setting expansion •
c- increases the strength •
12. TIN ( Sn ) 25-27% – 2 •
Influences the amalgam in an opposite •
manner to silver
a- decreases expansion •
b- decreases strength •
c- increases setting time •
13. Copper ( Cu ) 6%- 3 •
;Influences the amalgam as following •
a- increases strength •
b- reduce tarnish and corrosion •
c- reduces creep ( reduce marginal •
)deterioration
Note; new alloys called “ high copper “ contain 9 •
%to 30
These alloys have less marginal breakdown •
14. Mercury ( Hg ) 3% max- 4 •
Activates reaction with other alloy particles •
to produce different phases
;Other components •
ZINC ( Zn ) 1% or less- 1 •
Influences the amalgam •
Decreases oxidation of other elements •
15. Palladium ( Pd ) 1% or less- 2 •
Reduces corrosion* •
indium ( In ) 1% or less- 3 •
decreases surface tension •
Reduces creep and marginal breakdown •
Increases strength •
16. Note ; The final finish of the amalgam •
restoration should not be done until after the
amalgam is fully set
It should be delayed for at least 24 hours after •
condensation
It is preferably longer than 24 hours •
By waiting you can be assured that the reactions •
between the alloy and mercury will have been
completed and more corrosion resistant will be
created
17. Why the amlgam restoration should be finished •
?and polished
;For three major reasons •
to reduce marginal discrepancies and to - 1 •
create a more hygienic restoration
to reduce the marginal breakdown which will - 2 •
reduce the chance of recurrent caries
to prevent the tarnishing and to improve the - 3 •
appearance of the restoration
18. Important;;; Heat generation must be avoided •
The use of dry polishing powder and discs can •
easily raise the surface temperature above the
60 c. danger point
A wet abrasive powder in a paste form is the •
agent of choice
NOTE; Heat will not only damage the pulp but •
also draws mercury to the surface of the
restoration and an inferior restoration will result
19. Note; final polishing may be accomplished using •
a rubber cup with flour of pumice followed by a
high- luster agent , such as tin oxide
Note; amalgam has a coefficient of thermal •
expansion approximately twice that of tooth
structure
Note; the discolored corroded superficial layer •
frequently seen on the surface of a dental
amalgam restoration is most likely a SULFIDE
20. Note; The amount of mercury remaining •
dental amalgam after condensation
DIRECTLY AFFECTS the
porosity of restoration- 1 •
compressive strength of restoration- 2 •
corrosive resistance of restoration- 3 •
Note; the smaller condenser point , the •
greater is the pressure exerted on the
amalgam
21. Note ; the amalgam restoration is non toxic , •
mercury is poisonous
Mercury in the form of liquid &vapor represents a •
significant health hazard in dental office
The greatest potential hazard of chronic mercury •
toxicity comes from inhalation of mercury vapor
The vaporization is most likely to occur during •
condensation of the amalgam
Note; mercury hypersensitivity is very rare •
22. Note; a bite-wing radiograph is the best method •
to diagnose incipient carious lesions on the
distal surface of posterior
A diagnostic aid to be used as a last resort to •
confirm the presence of carious lesion on the
proximal surface of an anterior tooth is
mechanical separation by wedge
Note; when two teeth adjacent to each other •
have a class III lesions the dentist should
prepare the large one first and fill the smaller
one first
