DHE132 Lecture 1

the Chinese in 659 AD

1800

G.V. Black

• Replace or restore lost tooth structure
• Prevent decay
• Take impressions
• Finish, polish, clean a filling or prosthesis
• Replace lost soft tissue

• Protects the public
• Controls & regulates
• ✓efficacy
• Safety
• Meets standards

Set standards used to develop specifications and testing on am international level

• biocompatible
• durable
• nonreactive in acid or alkaline conditions
• compatible with other materialsesthetically acceptable

• there is NO adversity to living tissue
• Postoperative sensitivity
• Toxicity
• Hypersensitivity
• Documentation

the principles of engineering and biological systems to the design of new dental materials

mastication= Normal masticatory force on the occlusal surfaces of molar teeth averages 90 to 200(psi) pounds per square inch

• Tensile
• Compression
• Torsion
• Bending
• Shear

tensile

compression

torsion

bending

shear

the internal force that resists an applied force

the resulting distortion

crack = Strain = distortion occurs

6.2 to 7.0

moisture and acidity

[therefore leakage is an issue]

galvanic shock

An electrical current transmitted between twodissimilar metals in a solution containing electrolytes

metals + acid + moisture

• Expansion
• Contraction
• Percolation [gap openings] can occur
• Thermal conductivity
• CTE = coefficient of thermal expansion =
• heat = expansion\ cool = contraction\ CTE is the measure of these changes in volume or length in a given material

Gold or composite

When fluids, microorganisms, and debris from the mouth penetrate the outer margin of the restoration and progress down the walls of the cavity preparation.(not desirable)

• maintain position w/out displacement
• Mechanical or chemical

undercuts in the preparation

obtained through adhesion or bonding

• Acid etch
• Retention grooves
• Microabrasion etch 1st\ aluminum oxide forced onto the tooth by compressed air.

The ability of a liquid to wet or intimately contact asolid surface.

hue, chroma, & value

the dominant color

• intensity \strength or lack of [high\low]
• 

• how light or dark a color is [dark\light]
• 

• Location
• Tactile sensitivity
• Radiographs
• Air
• Magnification
• Illumination

• Strongest [because they involve the exchange of electrons]
• Three types:
• Ionic:[1 e- exchange = brittle/broken], covalent:[2 e- exchange = strong/hard/high melting point]
• Metallic:[multiple e- cloud [-] attraction]

• Much weaker
• No e- sharing
• Much deformation and fracturing

• Solid: has shape and volume
• Liquid: has volume but not shape
• Gas: has neither volume nor shape

has shape and volume

has volume but not shape

has neither volume nor shape

• is a combination of a solid and a liquid
• Most materials are mixtures of more than one state of matter.

• describes how the size of an object changes with a change in temperature; i.e.. ice
• + a measure of the change in length of an system over a given temperature range

is the tendency of matter to change in volume in response to a change in temperature

Mechanical and thermal changes

• strength to withstand biting and chewing forces
• Force load
• Stress
• Tensile
• Compressive
• Shear
• Strain

• Contraction & Expansion
• *Thixotropic

liquid[s] being able to flow more easily under mechanical forceCertain gels or fluids that are viscous in static conditions will become less viscous when shaken, agitated, stressed

• How much a material dissolves
• Able to dissolve in fluids
• Measured as:
• HighLow

change in shape or form

ability to bend considerably with small stress resulting

maximal stress a material can withstand without rupture or fracture

ability to withstand permanent deformation under a compressive load without rupture. (Gold is a malleable metal)

ability of a material to resist fracture

property of being easy to break or rupture (opposite of toughness)

the force which causes attraction between like molecules

the material to which the adhesive is applied (receiver of the adhesive)

spreading of a liquid over a rough surface. Promotes adhesion by providing more intimate contact between adhesive and adherend.

the ability of material to withstand permanent deformation under a tensile load without rupture

a chemical reaction that gives off heat

how a material is held in place by means such as the shape of the cavity preparation, etching the surface or placing retentive groves

(a substance) deforms under stress, but then returns to its original shape after the removal of the stress

the maximum stress a structure can withstand without being deformed permanently

(Young’s Modulus) that property which relates to the rigidity or stiffness of a material under stress

does not deform much when a stress is applied, it has a high elastic modulus. [it can withstand the strain]

Molecules in a liquid state

• its resistance to flow.
• The thicker the material, the harder it is for the material to flow.
• Film thickness [aka.the minimum thickness attainable] is important when dental cements are used

viscosity

thin fluids

thick fluids

used in the treatment of disease and include materials such asMedicated basesTopical applications for periodontal disease

directed toward the prevention of disease and the promotion of oral health.Preventive materials includeSealants

makes up the largest classification and include fillings, crowns, implants, etc.Restorative materials are further classified asDirectIndirect

• Reaction:
• Set mixing time
• Chemical
• Light
• Dual-cure
• Manipulation:
• Through
• Directions
• Accuracy
• Shelf Life:
• Storage
• Manufac. date

Occupational Safety and Health Administration

Center for Disease Control

Other Potentially Infectious Materials

Personal Protective Equipment

National Fire Protection Association

Material Safety Data Sheets

Environmental Protection Agency

American Dental Association

Globally Harmonized System

• US Department of Labor agency
• Mission: protect workers: physical, chemical and infectious diseases while at work
• Set standards: in work facilities [exposed to human body fluids]
• This OSHA standard is the ‘Bloodborne Pathogens Standard’:
• “Avoiding occupational exposures to blood is the primary way to prevent transmissions in health-care settings”. CDC (Center for Disease Control) 2003

• Employee training, safety, and documentation requirements
• New employee training within 30 days,
• when new chemicals introduced,
• once a year refresher
• Records are kept for 5 years or whiled employed + 30 days
• Exposure determination: low high risk

• Infection control
• Universal precautions
• Standard measures used
• Post-exposure follow-up
• PPE = Personal Protective Equipment
• Housekeeping/laundry

• PROTECTS EMPLOYEE [workers] and patient
• Disposal of biohazardous (regulated) waste
• Hired companies
• What about PCC?

• Offering of Hep.B Vaccination, and yearly TB testing
• Mandated training for dental Employees

Inspections of dental facilities as it relates to worker safety

• Gloves: utility and examination.
• Masks [particulate matter]
• Gowns. Long sleeved & fluid resistant.
• Fabric or disposable.
• Safety glasses. Protect from side and front.

• particulate matter
• Mercury
• toxic effects of chemicals
• airborne contaminants

• Inhalation
• Absorption through the skin
• Ingestion
• Invasion directly through a break in the skin

• Catch fire
• React or explode when mixed
• Be corrosive or toxic

inhalation

• Product identifier
• Signal word
• Hazard systems
• Precautionary statements
• Pictograms
• Supplier info.
• Supplemental info.

Material identityHazard warningsSupplier information

• Blue – health
• Red – flammability
• Yellow – reactivity
• White – what PPE needed for specific hazard (A-X)

4 = extreme hazard

3 = high hazard

2 = moderate hazard

1 = slight hazard

0 = no hazard

4  Danger: may be fatal on short exposure. Specialized protective equipment required

3  Warning: Corrosive or toxic. Avoid skin contact or inhalation

2 Warning: May be harmful if inhaled or absorbed

1  Caution: May be irritating

0  No unusual hazard

4 Danger: Flammable gas or extremely flammable liquid

3  Warning: Flammable liquid flash point below 100° F

2  Caution: Combustible liquid flash point of 100° to 200° F

1 Combustible if heated

0 Not combustible

4  Danger: Explosive material at room temperature

3  Danger: May be explosive if shocked, heated under confinement or mixed with water

2  Warning: Unstable or may react violently if mixed with water

1 Caution: May react if heated or mixed with water but not violently

0 Stable: Not reactive when mixed with water

W: Water Reactive

Oxy: Oxidizing Agent

Inhalation hazard

• Scope:
• Covers: all haz. Chemicals; substances; diluted solutions; mixtures; pharmaceuticals; food additives; cosmetics;
• Work exposure
• Transportation
• Enhanced Protection of peoples and environment
• Facilitation of international trade in chemicals
• Insuring more sound management of chemicals

žJune 1, 2015 complete modifications

žDec. 1, 2015 = last day to ship under “Old System”

• Dec. 1, 2013 = new labels & SDS
• June 1, 2016 complete GHS training

• Name
• Hazard label
• Correct number level
• Expiration date
• Manufacture if changed into different container.
• Original containers need to have expiration date

Flush area with water immediately for at least 5 minutes.

• Discuss requirements & standards
• Explain the hazards of the chemicals
• Protection measures
• Label accuracy
• Record keeping
• Differentiate/ maintain bio–living- aerosols