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RESTORATIVE MATERIALSDA 130 Dental Materials and Anatomy and Physiology
HISTORY OF DENTAL AMALGAM
Has been in use for over 150 years in dentistry
“Amalgam” actually means a mixture of metals Consists of Mercury: Alloy Alloy made up of varying percentages of silver, tin,
copper and zinc
Percentages of alloy and mercury were once mixed by the hand of the dental assistant Research soon discovered that mercury was a
hazardous material, so standards of handling were developed
WHEN DO WE USE DENTAL AMALGAM?
Dental amalgam is still considered a safe and effective means to restore a tooth
Amalgam is often used for: Primary and permanent teeth For stress bearing areas of the mouth (usually
posterior) For areas where moisture contamination is not a
concern For cost purposes When aesthetics is not a concern
MERCURY HAZARDS?
Although dental amalgam contains mercury, when it is mixed with the alloy, the chemical composition changes, and it becomes harmless
Mercury on it’s own is liquid metal, and considered hazardous Premeasured capsules prevent dental personnel
from handling mercury in it’s liquid state
HOW TO HANDLE DENTAL AMALGAM
There is still a risk to healthcare workers regarding dental amalgam; therefore: We use PPE when handling We use premeasured capsules We make sure we close the door of the triturator
when mixing amalgam Always use the suction during application to
prevent patient aspiration, which could lead to potential toxicity
Have a mercury spill kit handy if a spill should occur, do not vacuum up!
Have an amalgam scraps container to place excess amalgam, do not throw in garbage!
TRITURATOR AKA AN AMALGAMATOR
WHEN TO USE CAUTION WITH DENTAL AMALGAM: When mixing the dental amalgam
Mercury vapors will be released Keep door to triturator closed during mixing
When handling amalgam Use a no-touch technique (even with gloves on) Use instruments to pass material, never touch with
bare hands! When restoring a tooth with an existing amalgam
restoration Be sure to use your PPE, vapors are given off when
handpiece is in use When cleaning amalgam after completion of
procedure Place in a amalgam scraps container
A container with a tight lid and keep either dry or with a small amount of radiographic fixer
ADDITIONAL PRECAUTIONS:
Do not sterilize extracted teeth with amalgam restorations Waste haulers will remove for a fee
Replace amalgam traps at regular intervals Use a mercury spill kit if you have scraps or
loose mercury
AMALGAM ARMAMENTARIUM Basic set-up (mirror, explorer and college pliers) Spoon excavator Tofflemire and wedges (if needed) Amalgam carrier Amalgam well Condenser or plugger Carvers
Hollenback Cleoid/Discoid
Burnishers Acorn / Ball
Articulating paper forceps Triturator
PROCEDURE STEPS:
Patient is given local anesthesia Tooth is prepared – with a high speed and
low speed handpiece Tofflemire is placed – if there is
interproximal involvement) Medicaments placed (if necessary) – bases
or liners Amalgam is mixed – with triturator Amalgam is packed – into a
carrier
PROCEDURE STEPS: Amalgam is transferred – into the tooth Amalgam is condensed – using condenser Anatomy is carved – into amalgam with hollenback
and cleoid/discoid Tofflemire is removed Restoration is smoothed – using burnishers Tooth height is checked – using articulating paper Adjustments may be
necessary – return back to
carvers and burnishers Give patient post-operative
instructions
COMPOSITE RESTORATIVE PROCEDURE:
Composite has been the restorative material of choice for some time now
The growing concern of the public in regards to the safety of dental amalgam created the demand for high strength, aesthetically pleasing composite resin
COMPOSITION OF COMPOSITE RESINS:
Resin matrix: Dimethacrylate aka BIS-GMA: a fluid monomer (liquid)
Fillers: quartz and silica (minerals and crystal compounds)
Macrofilled: larger particles found in resin, known for high strength
Microfilled: smaller particles in resin, known for aesthetic qualities and ability to polish
Hybrid: most commonly used today, provide high strength and aesthetically pleasing results
Flowable: used in a syringe, this variation of composite is used for it’s flowable consistency
Dentist’s will often use this to place on floor of preparation Sealant composites: similar to flowable, but consistency is
even thinner to allow flow into pits and fissures of occlusal surfaces
THE RIGHT SHADE:
Critical to creating a cosmetic final result Use a universal shade guide
Unless a lab provides the office with a separate one
Take shade in natural light Turn dental light off
Use a hand mirror, and have patient approve shade prior to use Documentation of approval and selected shade is
also necessary
TECHNIQUE SENSITIVE:
Composite is affected by a number of factors, many of which the dental assistant can control: Moisture contamination
Saliva Light sensitive
Composite will begin to set if exposed to any light Considerations for use with other materials
Certain dental materials cannot be used with composite: Eugenol based medicaments Fluoride treatments Dental sealers (varnish)
MEANS OF ISOLATION:
ETCH AND BONDING AGENTS
Composite fillings are not created with mechanical retention, chemical retention is necessary
Acid etch – phosphoric acid Used to open enamel rods and dentin tubules Similar to sandpaper on wood Tooth should appear chalky white when properly
done. Primer is used to condition tooth and aids in
bonding Bonding agent unifies the tooth and material
MICROSCOPIC IMAGES OF ENAMEL RODS
Before etching After etching
MICROSCOPIC IMAGES OF DENTIN TUBULES
Dentin and nerve tissue
Enamel and dentinal tissue
ARMAMENTARIUM:
Basic set-up Spoon excavator Plastics instrument Condenser Burnisher Articulating paper forceps Matrix strips Composite/dispensing unit Acid etch Prime and Bond system Curing light
PROCEDURE STEPS:
Dentist administer local anesthesia to the patient
Shade is taken Always prior to preparation
Tooth is prepared – with dental handpieces Tooth is isolated – meaning, protecting the
tooth from moisture and contaminants Cotton rolls, dri-angles and rubber dam are indicated
Acid-etch is placed – creates porosities on the tooth surface Usually for 20-40 seconds
Thoroughly rinse for 20 seconds Replace wet cotton rolls
ETCH FIRST, THEN APPLY BONDING AGENTS
PROCEDURE STEPS Dry tooth Place primer – conditions tooth to receive bond Dry tooth Place bonding agent – allows for unification of tooth
and composite material Cure
With light for 20 seconds Place composite material
Flowable first on floor of prep Hybrid placed in layers and cured in increments
Final details are created Final cure – 40-60 seconds
FINAL STEPS
After completion of the procedure, the dentist will check the occlusion (how the patient bites)
Once optimal occlusion is achieved, the dentist will polish the restoration