What are sealants?
polymer coating to protect the teeth from further decay
What are the characteristic designs that allow for direct use?
light cured, flowable into pits
What is recommended to use before sealants to prepare the enamel?
etch
What is the major structural chemical used in sealant?
BidGMA-TEGDMA
Does sealant use fillers?
No
What type of bonding does the sealants have with the enamel?
mechanical
Are sealants meant to last a long time?
no but etching helps to extend longevity
What is macrotags?
larger interprism resin penetration
— looks like small notches in enamel
What are microtags and what is their purpose?
smaller penetrations into the enamel that provide the major retention of the sealant
How does oxygen inhibit sealants/polymerization?
interferes with radical polymerization via termination
thinner layer = bigger problem
The an adhesive layer usually hydrophobic or hydrophilic?
Both in order to bond with enamel and dentin
Do adhesive possess acid or basic groups that promote bonding
acidic
Are adhesive filled or unfilled?
unfilled or lightly filled
What two properties must flowable materials balance?
viscosity and mechanical properties
How does the resin viscosity correlate with mechanical properties?
increase in mechanical properties = increase in viscosity
How does increasing filler load affect the viscosity and mechanical properties?
increases viscosity and improves mechanical properties
Where in the tooth-adhesive-composite model does adhesive failure occur?
above adhesive
Where in the tooth-adhesive-composite model does cohesive failure occur?
in the middle of the adhesive layer
Where in the tooth-adhesive-composite model does structural failure occur?
in the dentin
What structures can interfere with adhesive bonding to tubular dentin?
The smear layer and plug
What is the smear layer and plug composed of?
ground collagen and hydroxy-appetite
How many steps are total-etch adhesives?
2-3
How many steps are self-etch adhesives?
1-2
How many steps are RMGI adhesives?
1
What are the 4 traditional steps for dentin bonding?
etch, prime, adhesive, restoration
Is the primer hydrophobic or hydrophilic?
hydrophilic
Can glass-ionomers be a cement, base, and/or liner?
cement and base
Can zinc oxide eugenol be a cement, base, and/or liner?
all 3
Can calcium hydroxide be a cement, base, and/or liner?
liner and base
What is characteristic of cements?
used to bind restoration of appliances to tooth structure
What are the three types of cements?
water-based
resin based
oil based
What are the curing mechanisms?
light cure
cold-cure for methacrylate
water cure for cements
What is the general scheme of chemical or cold cure?
mix part A and B to initiate polymerization
How does one control the balance between mechanical properties and viscosity?
more filler = high viscosity & modulus
more liquid = opposite and longer working/setting time
What is the powder to liquid ratio?
2.7:1
Do resin based cements use monomers that are high or low in MW?
Low
What are resin based cements used for?
ortho, cermanic corwns/bridges, veneers, inlays
What is 4-META modifier?
an additive to promote bonding in resin adhesives
What is zinc phosphate used for?
crowns
What is a liner?
realtively thin material used to protect dentin from residual reactants that diffuse out of the restoration/oral fluids that may penetrate leaky restorations
Do liners have a high or low viscosity
low
What solution liners are used under amalgam?
copal varnish
What solution liners are used under composite?
adhesives
What are the requirements of an extensive carie?
close to pulp (0.5 mm) or exposed pylp
What is used to protect the pulp in extensive caries?
calcium hydroxide liner
What is characteristic of CaOH2 liners?
paste reacts via acid/base calcium ions cross link insulator high solubility stimulates reparative dentin
What cell is stimulated by CaOH2?
odontoblasts
What is the brand name of CaOH2?
Dycal
What are the components of zinc oxide and eugenol?
reinforced powder, ZnO powder, eugenol oil of clove
What is the purpose of the oil of clove?
dulls pain (obtundent)
What are the restriction of zinc oxide and eunegol?
cannot be sued under composite and inhibits polymerization
What is the purpose of liners and bases?
protect the pulp
minimize post-op sensitivity (insulator and calm inflammation)
controls fluid movement
Define bases
Provide thermal protection for the pulp and mechanical support for restorations by distributing the stress across underlying dentin
What are the types of bases?
only water based
What is the reaction utilized by bases?
acid-base reactions
What are the characteristics of wax?
temporary melt at low temp carvable burn off stable dimensionally
Is the thermal expansion coefficient of wax small or large?
large