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