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Direct Restoratives

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Title: Direct Restoratives


1
Direct Restoratives
  • Chapter 5 6
  • Dental Materials
  • DAE/DHE 203

2
Part I Metallic Restorations
  • Amalgam Restorations
  • Gold Foil Restorations
  • Matrices and Margins

3
Amalgam
  • Metal Alloy Mercury Amalgam
  • Alloy a mixture of metals
  • Copper, silver, tin, zinc
  • Mercury (Hg) a metal with a low melting point
    making it liquid at room temperature
  • Makes the metal mixture moldable at room temp.
  • Allows for a direct restoration
  • A toxic metal the root of current public concern

4
Amalgam
  • Used in dentistry for almost two hundred years
  • Versatile, inexpensive, durable material
  • Self-seals its interface (with corrosion
    products)
  • Does not chemically bond to tooth
  • No studies of any major national international
    health organizations have ever linked it to
    disease or chronic illness
  • Considered safe effective by industry the
    profession

5
Amalgam
  • Using high-copper alloy since 1960s
  • Compared to low-copper amalgams
  • Require less mercury in the mix
  • Have increased strength
  • Less marginal breakdown
  • Less corrosion
  • Less creep (dimensional change under a constant
    stress)
  • Pre-dosed capsule
  • Convenient
  • Less handling of mercury
  • Proper/consistent mix of amalgam

6
Amalgam
COMPOSITION OF HIGH-COPPER ALLOY
METAL CHARACTERISTIC
SILVER 40-70 ? strength, ? corrosion, ? expansion
TIN 22-30 ? expansion, mixes with copper
COPPER 13-30 ? strength hardness
ZINC 0-1 used in manuf. process
55 60 ALLOY 40 - 45 MERCURY
7
Amalgam
  • Three forms (shapes) of alloy
  • Lathe-cut shavings of metal
  • Rough sharp edges, irregular shape
  • Spherical sprayed frozen metal droplets
  • Round or ovoid shaped
  • Admixed lathe cut spherical

Handling characteristics of amalgam vary with
alloy shape.
8
Amalgam Mixing
  • GOAL thorough mixing of alloy with mercury
  • trituration,amalgamation 5-20 seconds
  • Ideal - plastic mass
  • Shiny, moldable, cohesive
  • Over-triturated
  • sticky, shiny
  • Under-triturated
  • dull, dry, crumbly

9
Amalgam The Procedure
  • Tooth prepped, isolated, apply matrix
  • Liner, base, varnish, as needed
  • Triturate (per manufacturer)
  • Dispense (amalgam carrier), repeat as needed
  • Condense, repeat as needed
  • Carve
  • Check adjust/carve occlusion interproximally
  • Burnish
  • Polish after 24 hours
  • Patients to avoid chewing/grinding for about 8
    hours!

10
Amalgam Setting
  • High Copper Amalgam
  • Gamma-1 phase
  • Silver combining with mercury
  • Form a crystalline matrix
  • 40 of total volume of filling
  • Tin reacts with Copper
  • Tin-copper compounds
  • Initial setting time 5 minutes from trituration
  • Final amalgamation continues for several hours

11
Amalgam Longevity
  • Research ? 20 years
  • Private 8 - 10 years
  • Why replace amalgams?
  • Secondary decay
  • Bulk fracture
  • Marginal breakdown
  • Marginal gap ? decay??
  • Bonding agents help?
  • ? sensitivity
  • ? life of margin
  • ? strength reinforce bond

12
Amalgam Corrosion
  • Less of a problem with
  • high-copper amalgams
  • Surface darkened by tarnish
  • Marginal breakdown
  • Surface pitting galvanism
  • Reduced by
  • Thorough condensing
  • Burnishing polishing
  • Good OH, ? acidity

13
Mercury Handling Safety
  • Avoid skin contact with mercury wear gloves
    eyewear, use kit to clean-up a spill!
  • Avoid mercury vapor wear mask!
  • Re-cap capsule immediately after
    opening/dispensing
  • Dispose of empty capsules in a sealed plastic bag
  • Place amalgam scraps in a sealed container
  • under x-ray fixer solution
  • Use HVE water when removing/drilling amalgam
  • When amalgam is set, mercury is bound to other
    metals!

14
The Public Controversy
"There is no sound scientific evidence supporting
a link between amalgam fillings and systemic
diseases or chronic illness," ADA President
Robert M. Anderton says. "This is a position
shared by the ADA and all major U.S. public
health agencies and is a matter of public
record." Spaeth, Dental Practice Report,
Jul/Aug, 2002
15
The Public Controversy
CDC officials also say there is no proof that
removal of amalgam can cure some illnesses as ADA
protesters claim. While there have been a number
of case studies and anecdotal reports about
adverse effects from amalgam, no published
controlled studies have demonstrated systemic
adverse effects, says the CDC. There is also no
scientific evidence that general symptoms are
relieved by removal of existing amalgam
restorations. Spaeth, Dental Practice Report,
Jul/Aug, 2002
16
The Public Controversy
Legislative bills are being introduced in states
around the country by anti-amalgamists to abolish
the use of mercury in dental amalgams or the use
of dental amalgam altogether.
Anti-amalgam organizations have filed lawsuits
against amalgam manufacturers and the ADA and
local dental associations for conspiring to
hide the truth about amalgam from the public.
17
The Public Controversy
To Haley, the great amalgam debate is simple.
Mercury is toxic. Keep it out of the mouth. End
of story.
Can I prove that chronic exposure causes any one
specific disease? Well, that takes a long time
to do that kind of research. Its hard to prove
that. Removing amalgam would take an oxidated
stress off the the body a very significant
one. Boyd Haley, PhD Chemistry Dept.,
University of Kentucky Spaeth, Dental Practice
Report, Jul/Aug, 2002 (www.dentalproducts.net)

18
Direct Gold Fillings
  • AKA gold foil
  • Not used presently
  • Great material, but
  • NOT esthetic
  • Costly
  • Difficult procedure time-consuming
  • Gold firmly condensed into prep burnish
  • Foil, mat or powdered gold
  • Pure gold can weld w/o heat
  • Class V, buccal or lingual pits, small Class I

19
Matrices Margins
  • Margins of a restoration are to be flush with
    the tooth surface this may be most difficult
    interproximally
  • A matrix builds a border or wall for the
    restoration
  • Wedges are placed to conform the matrix to the
    tooth
  • Margin errors
  • Open margin a gap is left between tooth
    restoration
  • Flash a small amount of restorative above
    cavosurface margin
  • Overhang a large amount of restoration outside
    of margin
  • Submarginal the prep is under-filled
  • Margination the removal of overhangs

20
Part II Esthetic Restorations
  • Polymers Polymerization
  • Dentin Enamel Adhesives
  • Dental Composites
  • Glass Ionomers
  • Compomer Restoratives

21
Polymers Polymerization
  • POLYMERS
  • Long-chain of organic monomers
  • Bis-GMA urethane dimethacrylates
  • Comprised of carbon-carbon double bonds (CC)
  • Monomers linked together thru Polymerization
  • POLYMERIZATION
  • Creating a polymer through chemical reaction
  • Three methods (auto-, photo-, dual-cure)

22
Polymerization
  • Autopolymerization self-, or chemical- cure
  • Monomer base initiator (2 pastes/solutions)
  • Chemical initiator in the catalyst
  • Mixing of pastes begins reaction
  • Setting time varies with product
  • Disadvantages no control of working time
  • have to be mixed

23
Polymerization
  • Photopolymerization light-cure
  • One paste
  • Reaction initiated by visible blue light (not
    UV!)
  • Advantages control of working time no mixing
    less chance for bubbles
  • Disadvantages must cure incrementally keep
    material from light

24
Tips for Photopolymerization
  • Hold light source (tip) as close to tooth surface
    as possible
  • (1-2 mm)
  • Cure buccal, lingual occlusal surfaces with
    Class II III
  • Use eye protection operator and assistant!
  • Follow manufacturers directions for exposure
    time
  • Test light intensity periodically

25
Polymerization
  • Dual-Cure
  • Combination of auto- photo- polymerization
  • 2 paste system light-cure
  • Operator mixes pastes, applies material light
    cures
  • Advantage reassurance that material is curing
    at depth of restoration

26
Enamel Dentin Adhesives
  • Why? To improve the bond of the restoration
    with the tooth (dentin/enamel)
  • When? After the cavity prep is complete
  • What? A 3-step process etch, prime bond
    enhances chemical bond between bonding agent
    (resin) and restoration
  • Remember! Dont desiccate (dry-out) dentin!

27
Enamel Dentin Adhesives
  • 1. Acid Etching
  • Improves the retention of the restoration
  • Increases the surface area of the dentin
  • Removes smear layer from prep
  • Allows for penetration of bonding agent into
    dentin
  • Protect pulp exposures before using!
  • Phosphoric acid (35-37) gel or liquid
  • Isolate teeth, apply etchant, wait (5-15 seconds)
  • Rinse dont desiccate! blot prep to remove
    water

28
Enamel Dentin Adhesives
  • 2. Primer
  • Resin - monomer
  • Improves wettability of prep
  • Penetrates etched dentin tubules
  • Applied in a thin layer thinned with air blot
  • May require light-curing

29
Enamel Dentin Adhesives
  • 3. Bonding Adhesive
  • Un-filled or lightly filled resin
  • Adhesive bonds to collagen fibers in dentin
    mechanically locks-in Hybrid Layer
  • Applied in a thin, uniform layer
  • Light-cured 10-20 seconds
  • New generations being developed

30
Esthetic Restoration Posterior Composite
Decay 30 MOD, plus restoring buccal pit
Cavity Prep drill, etch, prime bond
Restored
31
Dental Composites
  • Mixture of materials
  • polymers (resins) glass particles (fillers)
  • plus pigments for shade variety
  • plus silane as a coupling agent (bond fillers to
    resin)
  • plus chemical to initiate the polymerization
  • Many types available
  • Filler material, particle size, and filler volume
    vary
  • Conventional, Microfill, Hybrids

32
Dental Composites
  • A challenge for users of resins
  • Polymerization Shrinkage
  • When monomer molecules are polymerized they take
    up less space/volume than when uncured (2
    shrinkage)
  • Solutions
  • Incremental Curing Allow for curing between
    layers
  • Use dentin bonding adhesives in prep site

33
Dental Composites
  • CONVENTIONAL COMPOSITES
  • Resin base large quartz fillers (50-60)
  • Good strength hardness
  • Difficult to polish well rough surface
  • Stains and discolors poor esthetics
  • Uses not used for restorations anymore may be
    used as an ortho cement

34
Dental Composites
  • MICROFILLED COMPOSITES
  • Resin base silica particle fillers (30-55)
  • Weaker material (? fillers)
  • Very high polish excellent esthetics
  • May be used as final layer of deep restoration
  • Use Great for anterior restorations (III, V)
  • (NOT Class IV)

35
Dental Composites
  • HYBRID COMPOSITES
  • Resin quartz or glass fillers (65-70)
  • Small or midsize particles
  • Minifills (largest particles are 1 2 um)
  • Midfills ( average particle size is 3 8 um)
  • Metals added to glass to make them radiopaque
  • Combination of esthetics durability
  • Universal use

36
Dental Composites
  • Flowable Composites
  • Hybrid with smaller and fewer particles
  • Dispensed thru canula tip
  • Maybe OK for Class V
  • Packable Composites
  • Hybrid with larger and more particles
  • Condensed with an instrument

37
Dental Composites
  • Handling Tips
  • Prevent cross-contamination of self-cure
    solutions
  • Take care to not incorporate bubbles upon mixing
  • Protect light-cure solutions from white light
    exposure
  • Protect composites from heat
  • Store composite materials in the refrigerator
  • Should have 2-year shelf life
  • May use metal instruments and matrices

38
Dental Composites
  • Able to use a more conservative prep
  • Offer great esthetics perhaps even tinting
  • Biggest reasons for failure in anteriors are
    discoloration recurrent caries adhesion is
    the key!
  • Reason for failure in posterior is marginal
    failure secondary caries
  • Should have a 5 10 year duration (Posterior
    Class IV have lesser duration)
  • May have limited success with Class V fillings
  • The composites can be layered to build strength
    adaptation to prep/margins

39
Glass Ionomers
  • Used for liner, luting cement restoration
  • Powder liquid
  • Inorganic Glass Organic Polymer water/acid
  • glass calcium aluminofluorosilicate
  • particle size restorations ? 40 um - thicker
  • lining/luting ? 25 um more flow
  • Liquid polyacrylic acid tartaric acid water
  • plus pigments for shades
  • Adheres to tooth surface releases fluoride

40
Glass Ionomers
  • Used for Class III and V restorations
  • (non-stress bearing areas)
  • Some forms strengthened with metal particles for
    use as a core build-up material (gray color)
  • Shrinkage of 3-4 - not as detrimental to bond
  • Tooth must be moist for adhesion
  • Soluble in water protect with resin or varnish
  • Not yet equal to esthetics of composites

41
Glass Ionomers
  • Conventional G.I.s
  • Liquid powder
  • Mix on paper pad or glass slab with spatula
  • Add ½ powder at a time
  • Finish mix in 30 seconds
  • OR
  • Triturate capsule for 10 seconds
  • Place into tooth (working time 2.5 minutes)
  • Use matrix to form surface
  • Will appear glossy when mixed

42
Glass Ionomers
  • RESIN-MODIFIED GLASS IONOMER
  • Resin added to mixture
  • Light-cure material - one paste no mixing!
  • Uses liners, bases
  • Added fillers have allowed use of
  • Resin-Modified G.I.s as core material or
    packable primary molar Class I material
  • Not recommended for high-stress areas

43
Compomer
  • A combination restorative material
  • Composite Glass Ionomer
  • Packaged and handle like composites
  • Formulated to releases fluoride less than
    G.I.s
  • Excellent esthetics
  • Not widely used as direct restorative
  • A few products on the market
  • (Brands Compoglass, Dyract, 3M F2000)

44
Part III Preventive Restorations
  • Dental (Enamel) Sealants
  • Preventive Resin Restorations

45
Dental Sealants
  • Applied to the pits fissures of healthy enamel
  • Prevent decay as long as sealant retained on
    tooth
  • Provides a physical barrier against decay-causing
    food/bacteria
  • Non-invasive conservative
  • Use acid-etch technique on enamel surface to be
    sealed

46
Dental Sealants Composition
  • Highly flowable monomer (resin) material
  • Unfilled vs, Filled
  • Self-cure or light-cure
  • Layer of air-inhibited uncured resin
  • Many various delivery systems
  • Opaque, clear, tinted
  • May be glass ionomer

www.nidcr.nih.gov/health/pub/sealants
47
Preventive Resin Restoration PRR
  • Conservative, preventive restoration
  • When frank decay is present in a groove or pit of
    the occlusal surface
  • Combines a composite filling with an enamel
    sealant. Both procedures are performed.
  • Decay is removed with a small, round bur
  • Composite is placed to fill the prep site
  • Sealant is placed to protect the filling rest
    of tooth
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