Adhesives and Bonding Flashcards
What is the procedure of bonding to enamel
etch enamel
rinse and dry
place enamel bonding resin
place restorative composite
The path of etch is similar to what
caries-cores of rods etch more and lateral sides near sheath
How much of the surface is etched
10µm of surface and penetrates 25-75µm
What is the strength of the acid used to etching
37% phosphoric acid
some 10% solutions being advocated total etch technique
What is the length of time for etching
15-20 sec
Why do primary teeth require a longer etching time
hyperfluornated
What is the proper timing for rinsing etch
10-20 sec
short rinse may leave debris
long rinse may weaken bond
What is the result upend contamination of etched enamel by saliva or secular fluid
it decreases the bond strength
must re-etch
What is the visual clue to determine successful etching
frosty white coloring
What are some drying techniques used to dry the etch
electric hot air dryers
HVE
three way syringe
liquid drying agents do not seem to do anything
What is the difference of etch pattern from gel to liquid
they are the same pattern!
can control gel pattern more
liquid etch is good for grooves and fissures
Bonding resin is made up of what
low viscosity resins (monomers)
After the bonding resin is places with a 10 sec cure, the composite is applied how
2mm increments
40 sec light cure
The remineralization of etched enamel can take up to how many months
2-3; fluoride can induce remineralization
Why is remineralization practical or not
etched enamel is probably polished off during finishing
protein matrix destroyed during finishing
Freshly cut etched enamel produces 25-50% greater bond strengths than uncut, why?
to get through the first amorphous enamel to get to the rods
This gives a good esthetic transition from tooth to material, the best marginal seal and minimum micro leakage, but a less durable restorative material margin configuration
a 45° exit
This conserves maximum tooth structure, produces weaker enamel bonds, can be optically more difficult to hide transition from tooth to material, most durable material margin configuration
90° exit
What is the procedure of bonding to dentin
etch dentin
rinse and dry
place dentin/enamel bonding resin
place restorative composite
This is an adherent layer of tooth debris, saliva, and bacteria which covers surface and plugs tubules to reduce dentin permeability, it offers weak cohesion and adhesion and must be addressed
smear layer
Newer dentin bonding systems remove this, which interferes with the resin bonding
smear layer
You must be aware of these changes in dentin
aging;
primary and secondary are organized
tertiary or repetitive is irregular
sclerotic dentin is high mineralized and response to mild stimulus
Cervical lesions can have either of these two things
sensitivity; open tubules
insensitive; transparant, discolored, occluded tubules
This relies on demineralization and is micromechanical
resin based dentin adhesion
This is difficult to etch, less collagen; use materials that rely on mineral RMGI or GI
sclerosed dentin highly mineralized
Must address the smear layer, how?
ionic and hydrophilic resins
establish micro-mechanical attachment to dentin surface
What are the three methods of attachment involving dentin
smear layer saturation
tubular penetration
resin impregnation
This is a self-etch system involving acidic monomers (phosphate esters/carboxylic acids); minor retentive feature
smear layer penetration
This is the penetration of resin down tubules; moderate retentive feature
tubular penetration
This is dentin demineralization, resin penetrating and wetting remaining collagen; major retentive feature
resin impregnation
What are three components of a dentin bonding system
conditioner or etchant
dentin primer
adhesive resin
This is used to remove the smear layer and cleans surface but does not demineralize dentin; mild acids
conditioner (RMGI)
This removes the smear layer, demineralizes dentin and leaves a pours surface
etchant (adhesive)
What is the total etch system
3 step system or 2 step
etch and rinse then either primer then adhesive or primer/adhesive at once
What is the self etch system
2 step or 1 step
etch/primer then adhesive
or all at once
This is a hydrophilic monomer mixed with solvent; increases smear layer permeability, penetrate wet collagen and provides micro mechanical retention
primer
This is light or unfilled resin; intermediate between primer and composite
copolymerize with primer and composite
usually both hydrophobic and hydrophilic
adhesive resin
Is this enamel or dentin bonding; provides long term durable bond
enamel
Is this enamel or dentin bonding; is not as predictable
dentin
Is this enamel or dentin bonding; this interface may exhibit microleakage
dentin
What is the first step in dentin bonding
acid etch the dentin surface to remove smear layer and create spaces between collagen network
After etching the dentin, what is the next step
apply dentin primer; hydrophilic solutions; penetrate and impregnate collagen
After applying the primer, what is the next step
apply adhesive; penetrates remaining porosities and provides a seal and hydrophobic surface
How would you apply composites in dentin bonding
in 2mm increments
What is dry bonding
all moisture is removed and the dentin is dehydrated
there is potential for collagen to collapse and it decreases permeability
What is wet bonding
all excess moisture removed
dentin surface is fully hydrated
collagen network is exposed
there is a thin layer of water but is removed by acetone based primers and resin replaces water without collapsing collagen network
What is the clinical significance of wet/dry bonding
bond quality
posterior sensitivity
What four things can contaminate dentin bonding
hand piece oil
intersulcular fluid
hemorrhage
air/water syringe
What four things play into the storage of bonding materials
evaporation
cross contamination
temperature
shelf life
When sealing dentin with resin, what is important to keep in mind
resin can penetrate the tubules toward the pulp
they are difficult to cure when mixed with fluid
unpolymerized monomer can leach into pulp; long term effects are unknown
What three things are associated with resin-resin bonding
applications
techniques
mechanisms
What are three resin-resin bonding applications
layering restorations; control color and shrinkage
resurfacing or repairing
cementation of indirect processed composite restorations (inlays, crowds, bridges)
What are the two types of resin-resin bonding
immediate delayed (>24hrs)
In immediate resin-resin bonding this unreacted bonding is left
air inhibited layer
This occurs after the light is removed regarding immediate resin-resin bonding
dark-cure polymerization
This under 10 minutes, new composite can be added directly to the surface, why
composite bonds chemically to air inhibited layer
If greater than 10 minutes or contamination, how can you add composite
clean with etchant and add layers of resin
In delayed resin-resin bonding, there is no what left
no unreacted bonds; no air inhibited layer
these are mechanical bonds
What do the mechanical bonds of delayed resin-resin bonding rely on
roughened surface
good wetting of material
When using a hybrid delayed resin-resin bonding what steps should you yake
roughen (diamond or microabrator)
acid etch
rinse and dry
place infilled resin - wets surface
