American Dental Association criteria for the standardization of new dental materials
Must not be poisonous or harmful to the body
Must not be harmful or irritating to the tissues of the oral cavity
Must help protect the tooth and oral tissues of the oral cavity
Must resemble the natural dentition
Must be easily formed and placed in the mo
__________ is any push or pull on matter.
Force
__________ is the reaction within the material that can cause distortion.
Stress
__________ is the change produced within the material that occurs as the result of stress
Strain
Pulls and stretches the material.
Tensile stress
Pushes the material together
Compressive stress
Breakdown of the material from lateral force.
Shear stress
A change in temperature in the oral cavity results from a hot or cold product.
Thermal Changes
True or False
Dental materials contract or expand at the same rates.
False
Dental materials contract or expand at their own rates.
Changes in temperature can cause a dental material to pull away from the tooth, causing:
Microleakage
Faulty restoration
An electrical current in the oral cavity can take place when there are 2 different metal is present.
Galvanic Action
What conditions must you have to allow these electrical currents to conduct?
Saliva contains salt(good conductor)
2 metallic components of different composition can act as a battery
What is the most common sign of corrosion?
Surface discoloration (can be removed easily with the use of polishing agents)
What can cause a reaction within a metal restoration?
Temperature, humidity and saline
Certain foods containing metallic forms that cause corrosion of a dental material.
The degree to which a substance will dissolve in a given amount of another substance.
Solubility
Example of a substance with low solubility.
Sand
Example of a substance with high solubility.
Sugar
Describe what a material look like if it is very flowable.
Liquidy
The strength that causes unlike materials to stick to each other.
Adhesion
Characteristics of dental materials that can affect the adhesion process are:
Wetting
Viscosity
Film thickness
True or False
A liquid flows more easily on a smooth surface than on a rough surface.
False
A liquid flows more easily on a rough surface than on a very smooth surface.
True or False
The thinner the film the stronger the adhesive junction.
True
This is the ability to hold 2 things together firmly when they will not adhere to each other.
Retention
A setting process of a dental material is initiated by what 2 actions.
Curing
To replace/bring something back to its natural appearance and function.
Restorative
To replace/bring something up to a pleasing appearance.
Esthetic
_________ materials are applied to the tooth while the materials is pliable and can be carved and finish.
Restorative
Direct Restoration examples
Amalgam
Composite resin
Glass ionomers
Intermediate restorative materials/IRM
Tooth whitening products
True or False
Amalgam is safe' affordable and durable material used predominantly to restore anterior teeth.
False
Used predominantly to restore posterior teeth (premolars and molars)
Indications for Using Amalgam
Primary and permanent teeth
In stress bearing areas of the mouth
When there is severe destruction of tooth structure
As a foundation of a crown
Poor POH
Moisture control is problematic
When the cost is overriding patient concern
Indications for NOT Using Amalgam
Esthetic is important
History of allergy to mercury or other amalgam components.
Cost of other restorative materials or treatment is not a factor.
Composition of Amalgam
Mercury 43-54%
Alloy powder 57-46%
Silver, tin, copper and zinc
Which metal alloy that gives amalgam strength?
Silver
Which metal alloy that gives amalgam for its workability and strength?
Tin
Which metal alloy that gives amalgam strength and corrosion resistance?
Copper
Which metal alloy that gives amalgam to suppress oxidation?
Zinc
2 Types of Direct Restorative Materials
Amalgam
Composites
Two forms amalgam is supplied in:
Capsules
Mercury in pellets
Can amalgam be used in anterior teeth?
Yes it can when esthetic is not a factor.
The most harmful route of amalgam toxicity for dental professionals.
Inhalation
Amalgam Hygiene Guidelines
Avoid mercury to come in contact with your skin.
Protect against spillage during trituration.
Keep the lid closed during trituration.
Do not discard amalgam in trash.
Collect and store scrap amalgam in a labeled hazardous waste container.
Container should
Health concerns for people who are exposed to high levels of mercury.
Tremors
Kidney dysfunction
Depression
Nervous system disorders
Types of Toxicity
Direct absorption (contact with the skin)
Inhalation (breathing in mercury; greatest hazard to DHCP)
Ingestion (swallow)
Amalgam supplied in pre-measured capsules
1 spill= 400mg
2 spill=600mg
3 spill=800mg
Pestle inside capsule is used to break the separating membrane in the capsule.
Activator
The process by which the mercury and alloy are mixed together to form the mass of soft amalgam.
Trituration
Precautions when handling mercury
Operatories should be well ventilated.
Store and waste amalgam in a sealed container.(EPA accordance)
Floors should be solid sheet of vinyl with no cracks.
Avoid excessive heat.(it vaporizes)
Use HVE when removing existing amalgam restorations.
Clean merc
What is the maximum level of exposure that is considered safe for occupational exposure in any 8 hour work shift over 40hr.work week?
50mg/cubic meter
Used to measure the amount of mercury found in the air.
Dosimeter.
What are the tests that can be taken to check the levels of mercury in the body?
Blood tests
Urine tests
True or False
Composite resin are stronger than amalgams or gold restorations.
False
Composite resins are not as strong as amalgam or gold restorations.
Indications for using composite resins
Restore Class I, II, III, IV, V restorations
Hypocalcification, attrition, abrasion and congenital abnormalities.
Closure of diastema.
Esthetic recontouring of teeth such as peg laterals.
Contraindications for using composite resins
Esthetic is not a factor
Poor POH
Cost is the significant factor in treatment decision.
Compositions of composite resins
Organic resin matrix
Inorganic fillers
Coupling agent
Pigments
A fluid like material called dimethacrylate also referred to as BiS-GMA.
Resin Matrix
True or False
The amount of filler, the particle size determine the strength and wear resistant characteristics of the material.
True
Types of composites
Macrofilled composites
Microfilled composites
Hybrid composites
Flowable composites
Sealant composites
Type of composites that has largest particles, greatest strength, duller, rougher surface and it is self-cured.
Macrofilled composites
Type of composites that has smaller fillers, highly polished finished restoration and used primarily in anterior restorations,
Microfilled composites
Type of composite that is used most often today, mixed range of particle sizes, smoother than macrofilled composite, has greater strength than microfilled composites, it has high resistance and has excellent shading characteristics.
Hybrid composite
Type of composite that is supplied as either a hybrid or nanofilled composite with enough filler included to make the material wear resistant and the material is designed to flow easier into the more conservative prep.
Flowable composites
Type of composite that is resemble flowable composites with less viscosity. This allow the material to flow into the tiny pits and fissures of the tooth surface.
Sealant composites
Three classifications of composites
Macrofilled
Microfilled
Hybrid
Which composite material can be used for most all cavity classifications?
Hybrid
Composition of composites which strengthens the resins by chemically bonding the filler to the resin matrix.
Coupling agent
Composition of composites that gives and match the color of the tooth. Most often the color comes from inorganic substance.
Pigments
True or False
You can use ZOE material under composite.
False
True or False
Placement of composite is accomplished by increments and light curing is performed before additional increments are added 2-3mm at a time.
True
A material that is light proof/individual units, will not polymerize until it is exposed to light and a kit will vary shades.
Composite
Is the process by which the resin material is changed from pliable state into a hardened restoration.
Polymerization
Curing time depends on
Manufacturers instructions
Thickness and size of the restoration
Shade of the restorative material used.
Instruments used to contour and polish a finished composite resin.
Finishing burs
Abrasive materials
Material hardens as a result of chemical reaction of the materials once mixed together.
Auto cured
Material does not harden until it has been exposed to a curing light.
Light cured
Curing takes place as the material is mixed and the final cure does not occur until the material has been exposed to a curing light.
Dual cured