WEEK 8 - DR POLSTER Flashcards
(30 cards)
Where do you look for etch instructions?
the manufacturers of the bond
How do you apply etch for a cavity with enamel and dentin?
selective etch (20-40s) wash and dry.
why do you etch?
to create microporosities
what happens if you etch for too long?
you ruin the structure of the enamel.
when do you know to stop etching?
when it develops a frosty appearance.
What happens if you etch for 40 seconds and there is no frosty appearance?
keep etching in 5 second increments
what does a frosty appearance after etching mean?
smear layer is removed
What are the components of primer?
MDP, HEMA, Camphorquinone and water
is 10-MDP mostly hydrophobic or hydrophilic?
Hydrophilic
What is 10-MDP?
an adheesive monomer that forms nanolayers through adhesion with hydroxylapatite.
what are the benefits of the nanolayers formed by 10-MDP
they are more resistant to degredation contributing to the longevity of the restoration.
is HEMA hydrophilic or hydrophobic
hydrophilic
what is the function of HEMA?
prevents phase separation which is the formation of water droplets in the hydrophobic resin.
what is the function of water in a primer?
acts as a solvent
what is the function of camphorquinone in dental primers?
it is a photo-initiator so it initiates the polymerization reaction
where do you apply primer?
to both dentin and enamel
how long do you leave the primer for?
20 seconds
what do you do after letting the primer sit for 20 seconds?
blow dry with mild air flow for more than 5 seconds until the rippling effect stops.
what does it mean when the rippling effect stops in primer?
the solvent has evaporated.
what is bond made up of?
10-MDP, Camphiquinone, HEMA, BIS-GMA
what is the function of BIS-GMA? Is it hydrophilic or hydrophobic?
hydrophobic, provides strength and reduces shrinkage.
how much bond should you use?
a sparing amount
how long do you cure bond?
5-10 seconds depending on the strength of the LED light
how long do you light cure each increment of resin?
20 seconds
