#objectives of this lecture :
1.To introduce the armamentarium used with
amalgam placement.
2. To describe the clinical sequence of amalgam
placement in occlusal cavities.
3. To describe the clinical sequence of amalgam
placement in inter proximal surfaces.
4. To describe the optimal safety management during
amalgam placement.
# preparation of amalgam cavity need special design & rigid sets of struction that we need to provide .
#the Aim not only to remove caries ,but also to provide amalgam restoration with enough strength to be able to withstand occlusal force.
# design of cavities is determined by filling material inside it and caries.
#retention : prevention of dislocation of restoration.
#resistance: prevention of fracture of restoration.
# amalgam instruments(open the slides ) :
1.amalgam carrier.
2. dappen's dish
3. amalgam condenser: tip of amalgam condenser is flat surface, so we can push amalgam into cavity.
# note : amalgam is a condensable material.
# we need to remove extra mercury bcz its toxin.
4. burnisher : to smooth the surface of freshly placed amalgam&to have shine amalgam .
5. amalgam carver : two sided tips (pointed tips &long shaft) to make cusps of amalgam.
#when we do activation of amalgam it will be in plastic phase & when it's dry it will be in rigid hard phase.
#if we have defective walls (so no walls support our amalgam restoration),we can't condense amlgm without matrix band &retainer otherwise it will pour into gingival sulcus.
#old info : in posterior upper molars the contact point is in the junction of oclussal and middle third of the crown & in posterior lower molar the contact point is in the middle .And the contact point is toward buccal.
# amalgam is a potentially hazardous material, bcz it contains mercury (toxic material).
#disadvantages of amalgam restoration :
1 -zinc alloy with amalgam will have expansion after setting(special case).
2 -but mainly the restoration material bserlha shrinkage after setting ,so we will have minimal space between amalgam &cavity invasion of bacteria and by product to pulp through dentinal tubulepost operative sensitivity.
Hala2 fe 7al la hal moshkele wl dr. 7aka enu will have Schizophrenia l2eno mara 7n7kelkom 7oto base aw liner w mara la2 enu el 7al .. but the most important thing we should know is this principle.
* principle : it is preferable not to put a base or liner underneath amalgam .bcz any thing under amalgam will not be as strong as amalgam ,so this will jeopardize the mechanical strength of amalgam.
- bss (el 7al ) we can have good seal of amalgam when we use smthing underneath amalgam and we suggest to use a bonding agent (has self edging properties)so it can edge and seal dentinal tubulelessen post operative sensitivity.
OR we can use glow(resin base material.)with amalgam to lessen post operative sensitivity.
3 -from biological point of view amalgam may cause chemical toxicity according to mercury.
4 -electrical danger & thermal expansion bcz amalgam contain metals "Gold crown" for example.
#amalgam capsule : has a membrane that separate the mercury from amalgam alloy.
-when we press it we will have activation .
-we use amalgamator to accelerate this process
-note : we can use amalgamator for other restoration material.
-normal set of amalgam need from 8-10 sec.
#amalgam placement in occlusal cavities (finally blshna n7ki bl cons !!)
-no need for matrix band & retainer .
-as u know we should have enough depth & width to use instrument
-the depth atleast should be 1.5 mm , but ! if caries were deeper 3 mm for ex. ,we should remove the caries and we should put liner underneath it bcz we are in direct contact with dentinal tubule.
-when we activate amalgam we put it in dappen's dish .
- it shouldn’t be over triturating l2nha bt6l3 mfasa5a 3n b3d .&it shouldn’t be under triturating cuase it will appear very shiness in order to unreactive mercury.
-so we need it solid & little pit shiny.
- ur cavity should be over filled with amalgam .
- if the cavity is deep ,we need to put first layer of amalgam and condense it then but the other layer and condense it , after that I start to do burnishing with the large tip at first (pre carving burnishing) ,next we do carving to remove the excess amalgam and we rely on the original tooth structure to have same anatomical&fissure system with adjacent teeth.
-now , we need to check occlusion .
> in completely edentulous patient ,we put patient into retruded contact position (centric relation ), so as to the centric occlusion will coincide with centric relation.
*this approach we call it reorganized approach.
> in dentulous patient , they have centric occlusion (maximum inter cuspation), that 98 % doesn’t coincide with retruded position (centric relation).
*so when we check occlusion ,we don’t retrude the mandible confermative approach.
# proximal amalgam placement :-
-here we put matrix band and retainer with widges .
-the extra thing here that we use prop to mark the outside part of marginal ridge(MR)
- we do carving for MR on two steps,
> first from outside next to adjacent tooth and we mark it with prop.
> then the inner part same as class 1 amlgam filling.
-be careful when u remove matrix band bcz amalgam now is little bit brittle (not completely set) so we need not to produce much forces or pressure into our amalgam ,so u need to slightly sliding matrix band then wedges .
-non contact amalgam : the extra amalgam that we didn’t use it.
- contact amalgam : that we use it and remove it with carver.
#Dental mercury hygieneRecommendations:
Amalgam contains mercury
Some Scandinavian countries has banned the use
of amalgam.
Training for the involved staff.
Remove professional clothing before leaving the
Surgery
#OFFICE settings
Well ventilated.
Use proper work area design to facilitate spill
containment and cleanup. Floor coverings should be
non absorbent, seamless and easy to clean.
Periodically check the dental operatory atmosphere
for mercury vapour. This may be done using
dosimeter badges or through the use of mercury
vapour analyzers for rapid assessment after any
mercury spill or cleanup procedure.
# HYGIENE RECOMMENDATIONS DURING
PREPARATION AND PLACEMENT OF
AMALGAM
Use only pre-capsulated amalgam alloys.
Use an amalgamator with a completely enclosed arm.
If possible, recap single-use capsules after use, store
them in a closed container and recycle them.
Use care when handling amalgam. Avoid skin
contact with mercury or freshly mixed amalgam.
Use high-volume evacuation systems (fitted
with traps or filters) when finishing or removing
amalgam.
# Mercury spills
Never use household cleaning products, in particular
those containing Ammonia or Chlorine.
Never use vacuum cleaners.
Never allow mercury to go down the drain.
Never use a paint brush to remove mercury.
Done by :khaled al-khatib.