DHE132 Lecture 1

  1. Silver paste was first mentioned by?
    the Chinese in 659 AD
  2. In the year ___, in France, silver shavings from coins were mixed with mercury to form a sloppy paste.
    1800
  3. In 1895, ___ developed the first viable amalgam formula
    G.V. Black
  4. Certified” materials are used to:
    • Replace or restore lost tooth structure
    • Prevent decay
    • Take impressions
    • Finish, polish, clean a filling or prosthesis
    • Replace lost soft tissue
  5. Food and Drug Administration (FDA)
    • Protects the public
    • Controls & regulates
    • ✓efficacy
    • Safety
    • Meets standards
  6. International Standards Organization (ISO)
    Set standards used to develop specifications and testing on am international level
  7. Materials used must be:
    • biocompatible
    • durable
    • nonreactive in acid or alkaline conditions
    • compatible with other materialsesthetically acceptable
  8. Biocompatibility:
    • there is NO adversity to living tissue
    • Postoperative sensitivity
    • Toxicity
    • Hypersensitivity
    • Documentation
  9. Biomechanics:
    the principles of engineering and biological systems to the design of new dental materials
  10. Force =
    mastication= Normal masticatory force on the occlusal surfaces of molar teeth averages 90 to 200(psi) pounds per square inch
  11. Types of forces:
    • Tensile
    • Compression
    • Torsion
    • Bending
    • Shear
  12. Image Upload 1
    tensile
  13. Image Upload 2
    compression
  14. Image Upload 3
    torsion
  15. Image Upload 4
    bending
  16. Image Upload 5
    shear
  17. Stress =
    the internal force that resists an applied force
  18. Strain =
    the resulting distortion
  19. stress
    Image Upload 6
  20. strain
    Image Upload 7
  21. If the stress within the object can not take the applied force, it will
    crack = Strain = distortion occurs
  22. pH of saliva is
    6.2 to 7.0
  23. Material selection (metals especially) suffer from the effects of
    moisture and acidity
  24. Tarnish and Corrosion occur
    [therefore leakage is an issue]
  25. When the current stimulates the pulp it is called
    galvanic shock
  26. Galvanism:
    An electrical current transmitted between twodissimilar metals in a solution containing electrolytes
  27. These 3 elements will produce and electric current (Galvanism)
    metals + acid + moisture
  28. Temperature effects:
    • 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
  29. Which is the better conductor of temperature?
    Gold or composite
  30. MICROLEAKAGE
    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)
  31. Retention =
    • maintain position w/out displacement
    • Mechanical or chemical
  32. Mechanical retention =
    undercuts in the preparation
  33. Chemical retention =
    obtained through adhesion or bonding
  34. Forms of retention
    • Acid etch
    • Retention grooves
    • Microabrasion etch 1st\ aluminum oxide forced onto the tooth by compressed air.
  35. Wetting:
    The ability of a liquid to wet or intimately contact asolid surface.
  36. The three components of color
    hue, chroma, & value
  37. Hue is
    the dominant color
  38. Chroma
    • intensity \strength or lack of [high\low]
    • Image Upload 8
  39. Value
    • how light or dark a color is [dark\light]
    • Image Upload 9
  40. What are some ways of detecting restorative materials?
    • Location
    • Tactile sensitivity
    • Radiographs
    • Air
    • Magnification
    • Illumination
  41. Primary bonds
    • 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]
  42. Secondary bonds
    • Much weaker
    • No e- sharing
    • Much deformation and fracturing
  43. 3 basic physical structures of  a  material
    • Solid: has shape and volume
    • Liquid: has volume but not shape
    • Gas: has neither volume nor shape
  44. Solid:
    has shape and volume
  45. Liquid:
    has volume but not shape
  46. Gas:
    has neither volume nor shape
  47. Plaster
    • is a combination of a solid and a liquid
    • Most materials are mixtures of more than one state of matter.
  48. Linear coefficient of thermal expansion
    • 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
  49. Thermal expansion
    is the tendency of matter to change in volume in response to a change in temperature
  50. If a material is going to be sitting in the human mouth it must be able to withstand:
    Mechanical and thermal changes
  51. Mechanical:
    • strength to withstand biting and chewing forces
    • Force load
    • Stress
    • Tensile
    • Compressive
    • Shear
    • Strain
  52. Thermal Change
    • Contraction & Expansion
    • *Thixotropic
  53. 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
  54. Solubility/ Soluable
    • How much a material dissolves
    • Able to dissolve in fluids
    • Measured as:
    • HighLow
  55. DEFORMATION:
    change in shape or form
  56. FLEXIBILITY:
    ability to bend considerably with small stress resulting
  57. ULTIMATE STRENGTH:
    maximal stress a material can withstand without rupture or fracture
  58. MALLEABILITY:
    ability to withstand permanent deformation under a compressive load without rupture. (Gold is a malleable metal)
  59. TOUGHNESS:
    ability of a material to resist fracture
  60. BRITTLENESS:
    property of being easy to break or rupture (opposite of toughness)
  61. COHESION:
    the force which causes attraction between like molecules
  62. ADHEREND:
    the material to which the adhesive is applied (receiver of the adhesive)
  63. WETTING:
    spreading of a liquid over a rough surface. Promotes adhesion by providing more intimate contact between adhesive and adherend.
  64. DUCTILITY:
    the ability of material to withstand permanent deformation under a tensile load without rupture
  65. EXOTHERMIC:
    a chemical reaction that gives off heat
  66. MECHANICAL RETENTION :
    how a material is held in place by means such as the shape of the cavity preparation, etching the surface or placing retentive groves
  67. ELASTICITY:
    (a substance) deforms under stress, but then returns to its original shape after the removal of the stress
  68. ELASTIC LIMIT:
    the maximum stress a structure can withstand without being deformed permanently
  69. MODULUS OF ELASTICITY:
    (Young’s Modulus) that property which relates to the rigidity or stiffness of a material under stress
  70. A stiff material:
    does not deform much when a stress is applied, it has a high elastic modulus. [it can withstand the strain]
  71. Flow=
    Molecules in a liquid state
  72. The viscosity of a liquid is
    • 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
  73. Retention is effected by
    viscosity
  74. low viscosity =
    thin fluids
  75. high viscosity =
    thick fluids
  76. Therapeutic
    used in the treatment of disease and include materials such asMedicated basesTopical applications for periodontal disease
  77. Preventive
    directed toward the prevention of disease and the promotion of oral health.Preventive materials includeSealants
  78. Restorative
    makes up the largest classification and include fillings, crowns, implants, etc.Restorative materials are further classified asDirectIndirect
  79. Things to consider about materials
    • Reaction:
    • Set mixing time
    • Chemical
    • Light
    • Dual-cure
    • Manipulation:
    • Through
    • Directions
    • Accuracy
    • Shelf Life:
    • Storage
    • Manufac. date
  80. OSHA =
    Occupational Safety and Health Administration
  81. CDC =
    Center for Disease Control
  82. OPIM =
    Other Potentially Infectious Materials
  83. PPE =
    Personal Protective Equipment
  84. NFPA =
    National Fire Protection Association
  85. MSDS =
    Material Safety Data Sheets
  86. EPA =
    Environmental Protection Agency
  87. ADA =
    American Dental Association
  88. GHS =
    Globally Harmonized System
  89. OSHA Occupational Safety and Health Administration
    • 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
  90. OSHA:  required Exposure Control Plan
    Blood-borne/Hazardous Materials
    • 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
  91. To control possible exposure:
    • Infection control
    • Universal precautions
    • Standard measures used
    • Post-exposure follow-up
    • PPE = Personal Protective Equipment
    • Housekeeping/laundry
  92. OSHA  regulations:
    • 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
  93. PPE: Personal Protective Equipment
    • Gloves: utility and examination.
    • Masks [particulate matter]
    • Gowns. Long sleeved & fluid resistant.
    • Fabric or disposable.
    • Safety glasses. Protect from side and front.
  94. Hazardous Materials in the Dental Office
    Exposure to :
    • particulate matter
    • Mercury
    • toxic effects of chemicals
    • airborne contaminants
  95. Pathways of exposure:
    • Inhalation
    • Absorption through the skin
    • Ingestion
    • Invasion directly through a break in the skin
  96. Hazardous chemicals can
    • Catch fire
    • React or explode when mixed
    • Be corrosive or toxic
  97. Which is the most severe pathway?
    inhalation
  98. GHS
    • Product identifier
    • Signal word
    • Hazard systems
    • Precautionary statements
    • Pictograms
    • Supplier info.
    • Supplemental info.
  99. NFPA
    Material identityHazard warningsSupplier information
  100. NFPA (National Fire Protection Association)       Chemical Hazard Labels
    • 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
  101. Health (Blue)
    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
  102. Flammability (Red)
    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
  103. Reactivity (Yellow)
    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
  104. Special Notice Key (White)
    W: Water Reactive

    Oxy: Oxidizing Agent

    Inhalation hazard
  105. GHS scope & Benefits
    • 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
  106. Chemical manuf. compliance dates:
    žJune 1, 2015 complete modifications

    žDec. 1, 2015 = last day to ship under “Old System”
  107. Employer compliance dates:
    • Dec. 1, 2013 = new labels & SDS
    • June 1, 2016 complete GHS training
  108. Per OSHA standards Every container with chemicals or materials needs to be labeled with:
    • Name
    • Hazard label
    • Correct number level
    • Expiration date
    • Manufacture if changed into different container.
    • Original containers need to have expiration date
  109. Eye wash, body wash station
    Flush area with water immediately for at least 5 minutes.
  110. SDS (Material Safety Data Sheets) SDS Explanation
    As an operator you must be able to:
    • Discuss requirements & standards
    • Explain the hazards of the chemicals
    • Protection measures
    • Label accuracy
    • Record keeping
    • Differentiate/ maintain bio–living- aerosols
Author
dentalhygiene
ID
337657
Card Set
DHE132 Lecture 1
Description
DHE132 Lecture1
Updated