Test #1-2 Flashcards
What are the qualities that are needed for a base
- thick
- absorbs biting forces
- thermal insulation
- irritation to stimulate secondary dentin
what is the current belief that pulplal sensitivity is caused by
micro leakage not temp change
what is not preferred over a base material
bond, eliminates microleakage
what can be used as a base
any dental cement
what base cant be used under composite materials
ZOE
What base has a stronger matrix, has less effect on pulp due to neutral ZOE
EBA (ethoybenzoic)
why must zinc phosphate be mixed on a cool glass slab
exothermic*
Zinc oxide powder is mixed with __________ initial set is very_________
phosphoric acid, acidic
what is zinc phosphate not recommended for
deep cavit prep unless a layer of calcium hydroxide is first placed
what is the acidity like of polycarboxylate
acidic- but ph rises with time there fore its kinder to pulp
what restorations can polycarboxylate be placed under
all restorations, usually amalgam
what is the primary use of polycarboxylate
cement
what is the most popular base
glass ionomer
what are qualities of glass ionomer
strength, bonding, fl2, non irritating, anticariogenic
what are qualities of glass reinforced polymer
bonds to dentin, releases fl2
because glass ionomer is a polymer what else can it bond to
other polymer materials used in restorations
b/c glass ionomer bonds what does it reduce
microleakage at the interface
glass ionomer can be used under
all restorations
what are resin cements
fluid composites, less fillers
what are some examples of resins
mouthguards, bleach trays dentures, partials
what material will be used when the restoration is temporary
ZOE
what material will be used in a deep cavity prep
calcium hydroxide
what is used as a bonding agent under esthetic polymers, glass ionomers, composite and hybrids
acrylic resin/glass ionomer
What are varnishes being replaced by
bonding agents
What are varnishes used for
to seal cut dentin
T/F varnishes dissolve slowly in oral fluids and is not permanent
True
What is the name of an intermediary material-varnish
copalite/universal varnish
What is a Liner used for*
to seal dentin and medicate pulp
What does calcium hydroxide stimulate
secondary reparative dentin
What 2 things seals dentinal tubules
varnish, glass ionomer
What kind of pH does calcium hydroxide have
basic
Calcium hydroxide dissolves in oral fluids
true
what happens when calcium hydroxide dissolves
it raises the pH which neutralizes the pH and decreases bacterial growth
What kind of restorations can calcium hydroxide be placed under
all types of direct restorations
What is calcium hydroxide being replaced with
bonding material that is not soluble and doesnt weaken the tooth
What are the 3 types of intermediary materials
base, varnish, liner
what does a base do
absorbs biting forces and insulates pulp
what does a liner do
reduces acidity, stimulates pulp and is a bonding material
What restorative materials are tooth colored filling materials
esthetic direct restorative materials
This is used for direct restorations, core buildups, veneers, sealants and cement
composite
what is a BLEND direct restorative material
a combination of composite and glass ionomer
WHat is compomer direct restorative material
hybrid of composites and glass ionomer cements
what is a polyacid modified glass ionomer direct restorative material
more glass ionomer than composite
what is a polyacid modified resin composite
more composite than glass ionomer
what is important to remember about composites, glass ionomers and blends
they are all polymers with reinforcing particles locked in the polymer framework
what restores form and function, bonds chemically with other polymers and effectively seals cut dentin
composite and glass ionomer
what is polymethyl/methacrylate PMMA*
a polymer made up of multiple methacrylate monomers
What is a Dimethacrylate resin*
reaction between bisphenol-A and glycidyl methacrylate= Bis-GMA**
What kind of polymer is a dimethacrylate resin
a cross linked polymer
Bis-GMA has what*
larger molecules therefore less polymerization shrinkage than methacrylate monomers
Triethylenglycol Dimethacrylate (TEGDMA)*
dimethacrylate
reduces viscosity
both bis-GMA and Tegdma are used in composite resins T/F
true
What are the advantages and disadvantages of Urethane Dimethacrylate*
Advantage-low viscosity
disadvantage- more brittle, more polymerization shrinkage than bis-GMA
What is the composition of Composites
monomer-dimethacrylates (Bis-GMA, TEGDMA, URethane)
What kind of filler particles are used in composites
silicates (quartz), radiopaque materials (Barium, strontium, zinc) and silane (bonds matrix and fillers)
What are the classification sizes of fillers:*
Macrofill 10-20 microns
Midifill .1-10microns
Microfill .01-.1 microns
What kind of particles are in a hybrid composite*
combination of sizes, gives increase strength and polishability
Why is a composite flowable*
less fillers more resin
What is affects shrinkage during polymerization
-shape of prep and intensity of light
what are characteristics of composite
- shrinkage-polymerization
- low thermal conductivity
- resin absorbs water
- thermal expansion
What is bonding
formation of resin layer that connects the primed surface to the overlying restoration
What is the smear layer
the compacted debris on enamel or dentin from cavity prep
What is the composition of Glass ionomers
organic, ionic polymer
silicate glass
fluoride
What is the polymerization of glass ionomers
chemically activated
light activated
dual cure
what are characteristics of glass ionomer
thermal expansion similar to tooth bonds to enalel and dentin high compressive strength low tensile strength slightly soluble in water
What are glass ionomers used for
restoratives
cements
bases/liners
