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Amalgam
Alloy of Mercury = Silver: Sn Copper: Cu Tin Zinc: Zn
What metal in amalgam is a base metal and highly susceptible to corrosion in the mouth?
Silver
Why is copper added to amalgam?
Reduce rate of corrosion in amalgam To make it last longer
Tofflemire/Matrix Band Retainer
To maintain stability of matrix band during condensation of restorative material for class II preparation
Wedge with Tofflemire used to
Create a tight contact and prevent an over hang
In order to detect an overhang, visible on an xray, which in instrument in your cassette would you pick up?
Explorer (Shepards hook)
Bonding agent is used to establish
micro-mechanical retention with tooth structure.
Phosphoric acid etch is used to
create a roughened tooth structure in order to increase surface area for micro-mechanical retention.
Enamel is ______________ mineralized and is the ___________________ tissue in the body.
96%, hardest
Phosphoric acid etch is used for __________ secs and ______________ enamel.
15-20, demineralize.
When enamel is etched is appears...
Frosty!
What happens if we get etch on the dentin?
Destroy smear layer and dentinal tubules are now open.
If dentinal tubules are open, what happens?
Pain
Light cure products work by
Photo-initiators and cause chem reaction to polymerize.
2 reasons for bonding failures
-Salivary contamination -Oil contamination (from prophy paste)
Number one cause for bonding failure is....
Salivary contamination
Rubber dam is used to
isolate the restorative field from the rest of the mouth.
Sealants are
barriers that protect occlusal surface from bacterial assault.
What is the best way to prep an occlusal surface for sealant placement?
Prophy jet or Cavi jet
Steps for sealant placement
Pumice/ prophy jet - Rinse isolate dry
Etch - rinse dry
Apply/ wick off excess
Polymerize (light cure)
Check retention/ occlusion
Composites are
Esthetic restoration made with a bonding agent = micro- mechanical retention with tooth structure
Composites are made from
silicates, quartz, glass = filled with tooth colored particles
What are added to composites so they appear radiolucent on xrays?
Silicates, quartz, glass
Barium and Strontium are added to composite resins for....
Radiopacity
Handling characteristics, classification and clinical application of composites are dependent on...
Filler particle size.
Microfill particles in composite = Midifill particles in composite = Nanofill = Blended all =
Nerds + Jelly beans + Sugar = Nanofilled micro-hybrid
Liners are used
Seal dentinal tubules or Seal and medicate the pulp
Calcium hydroxide is used to
Seal dentinal tubules medicate the exposed pulp horn Stimulate odontoblast to stimulate reparative dentin = NO RCT
Zinc Oxide Eugenol (ZOE)
Liner Oil of clove = soothing to pulp Cannot use under a composite
Resin-modified glass ionomer
Most popular liner used today bonding agent that has glass ionomer powder and releases Fluoride
Bases
Insulate and protect the pulp
Cements are
nonconductive and have compressive strength
Liner only when
small dentinals are exposed = small cavity
Base & Liner is used when
large cavity and pulp is exposed = pink no bleeding to insulate & reduce sensitivity
Zinc phosphate is a _______________ ______________.
exothermic cement = generates heat. Mixed on glass slab
Which of the following cements generates heat when mixed? A: Zinc Eugenol B: ZInc phosphate
B: Zinc phosphate
Polycarboxylate cement must be mixed with.....
polyacrylic acid liquid
Glass Ionomer cement
-Binds to dentin -Releases fluoride -Expands/contracts ike tooth structure -Can be used as a class V restorative material
Resin cements
USed for esthetic situations
Resin based glass ionomer
Hybrid cement = viscosity
Zinc- Oxide Eugenol cement is used for
Temporary crowns, soothes pulps
How do you clean zinc-oxide eugenol?
Orange solvant
Elastomeric
Material with elastic properties = think elastoman = flexible
2 Elastomeric materials
Water soluble = hydrophilic (loves H2O) Water insoluble = hydrophobic (hates H2O)
Water soluble elastomerics
Hydrocolloids = Reversible (agar) Irreversible (alginate)
Agar undergoes a reversible reaction is because undergoes a
physical reaction.
Solidification by cold is called..
gelation
Hydrocolloids Irreversible (alginate) undergoes change by a _______________ reaction.
Chemical
Cold water _____________ sets alginate and warm water _______________ alginate set time.
slows, accelerates
Syneresis means (alginate)
Loss of a solvent by a solute = to shrink = losing water to atmosphere
Imbibition means (alginate)
Absorption of a solvent = to swell = taking on water
Why do we aerate the alginate powder?
Because it is a fine powder
Elastomeric insoluble
polyether rubber
Which of the hydrophobic impression materials distorts when left in water?
Polyether rubber
Gypsum
calcium sulfate dihydrate = 2 molecules of water
How do we get alpha or beta calcium sulfate hemihydrate?
from calcium sulfate DIHYDRATE = heated and water extracted
To use gypsum we need to ...
add the water back = expands as it sets!
The more water we add to gypsum, the ______________ _________________.
greater expansion = lower compressive strength.
Beta calcium sulfate hemihydrate gypsum is
Plaster = big expansion, particles further apart = takes a lot of water and is lower compressive strength
Alpha calcium sulfate hemihydrate gypsum is
Stone = less water = less expansion and higher strength.
Put in order the weaker to stronger gypsum products. Alpha STONE Beta PLASTER Alpha DIE STONE
Beta Plaster Alpha Stone Alpha Die Stone *** Think A id better than B ****
Diestone contains
a chemical additive to make it stronger
Diestone is used for
working models by lab techs
What 2 agents can modify gypsum products?
Borax = slows it down (think burro = slow donkey) Potassium sulfate = speed up (think eating a banana will make you fast)
A model base should be trimmed
perpendicular to the midline
What is inlay wax?
Wax used by the lab tech to create the waxed patterns on models
Waxes are
modified paraffins
Utility was is used for..
cushion ortho brackets and appliances modify an impression tray to cushion edges
Casting alloys
used to make inlays, onlays, creons, bridges
Inlays fit
"in the tooth, in the cusp"
Onlays fit
cover the cusps
Casting alloys are categorized by
alloy composition = precious or non-precious metals
Precious alloys are
noble metal = last a long time and resistant to tarnish and corrosion. Gold, platinum & palladium
Non-precious alloys are
Base metals = tarnish & corrosion Nickel: 50% females have Nickel allergy
Do not treatment plan for a PFM for a patient that has a metal allergy because
gingival tissue will never heal due to allergy
How do we polish gold in the mouth?
Tin oxide = okay in mouth
Why cant we polish gold in the mouth with rouge?
Because it is toxic
T or F: Gold foil will always look like gold
True and will always be at the gumline or front of the mouth = have to hammer = 1st premolar to premolar.
Implants are used because
they are biocompatible alloy of titanium
Endosteal means
within bone
Failure of implants is due to
No integration Inadequate bone Peri-implantitis (inflm around implant)
Contraindications for implants
Inadequate bone Periodontal disease Uncontrolled diabetes Smoking Infection Bisphosphonates
Bisphosphonates
increase bone density, but decrease vascularity = decrease healing potential.
Can we use an electric toothbrush and air polisher on an implant crown?
YES
Do we scale implant with a metal instrument?
No, never
Pyrophosphates are
tarter control toothpastes = leading cause of dentinal sensitivity
Triclosan
ACTIVE ingredient in gum care toothpaste = antiseptic
Potassium nitrate Sodium Citrate Strontium Chloride are all ingredients found in what toothpaste?
Active ingredient in Antihypersensitivity Toothpastes
Hydrogen peroxide Carbamide bicarbonate are active ingredients in which toothpastes?
Home bleaching pastes
Sodium bicarbonate is the active ingredient in..
denture cleansers
Thermoplastic polymer is used for
mouthguard fabrication
Polymethylmethacrylate & Bis-acrylic resins are used for?
Temporary crown restorations
Which dental tissue most look like enamel?
Porcelain
Galvanism is
Generation of electrical current when dissimilar metals are in an acidic environment
Irreversible hydrocolloid
alginate
Tensile
capable of being stretched
Ductility
Ability of material to undergo a change in shape of from without breaking
Malleability
materials capacity to be shaped by force or pressure
Compressive strength
the force a material can withstand before breaking
Final mercury content on high copper amalgam restorations is
50 % or less
Note 
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