1. C - Bonding Theory Flashcards
Describe the Total Etch (4th Gen) systems.
- 3 - step bonding adhesives
- Etch
- Primer
- Bonding resin
- Most sensitive technique
- Gold Standard
- Highest bonding values
Which bonding adhesive system is the gold standard and has the highest bonding values?
Total Etch Systems - 3-Step Bonding Adhesives
(4th Generation Adhesives)
All-bond 2, Scotchbond MP, Optibond FL
Describe the 5th Generation (2-step) adhesives.
- 2-step adhesives
- Etch
- Prime/Bonding resin (single bottle)
- Enamel is poorly etched
Which 5th generation adhesive has a neutral pH?
Prime & Bond
Describe the 6th generation bonding system.
- 2 steps
- Etch & Prime (H2O)
- Bonding resin
- Self-etch
What are the names of the 6th gen adhesives?
- Clearfil SE Bond
- Liner Bond II
Describe the Self-Etch systems.
- “All-in-one” adhesives
- Etch/Primer/Bond
What are the main pro’s and con’s of the self-etch systems? (single step)
- Pro’s
- pH can be lowered to etch uncut enamel
- Lower sensitivity
- Less technique sensitive
- Con’s
- pH is still limited, smear layer retained
- Water entrapment in hybrid layer
What type of adhesion system has the “true bonding”?
Glass Ionomers
Why don’t you use glass ionomers as a luting agent for all ceramic restorations?
- Water expansion
What are the steps in forming good adhesion?
- Clean adherend
- Good wetting
- Intimate adaptation
- Bonding
- Good curing
What is the performance factor that is the biggest variable for success?
Operator - technical ability, age, eyesight, etc
What are the 5 performance factors?
- Operator
- Design
- Materials
- Intraoral Location
- Patient
What is the function of dentin bonding primers?
- Displace water and allows monomers to penetrate dentinal collagen matrix
- Alcohol or acetone evaporates and removes water
- Promotes infiltration into collagen
What does dried enamel do for bonding strength?
- It increases the surface energy allowing hydrophobic resin to impregnate the rods with deep resin tags
What is the majority of our “dentin bonding”?
Intertubular dentin
What are the factors affecting dentin adhesion?
- Dentinal wetness
- Smear layer
- Isolation
Can you rinse away the smear layer?
No, but etch and rinse will, self-etch maintains it
The smear layer may reduce dentin permeability by as much as ____?
86%
What creates a thick smear layer?
Diamond burs
Where do the “water trees” form?
Under the hybrid layer
What is the C-factor?
- Ratio of bonded resin surface/un-bonded resin surface
- Higher C factor = more shrinkage & strain
What is the elastic bonding concept? (tensile buffering)
- When composite is cured and shrinks
- A more elastic bonding resin layer allows the resin interface to stretch
- This preserves the hydrbid layer
Filler = more elastic
Describe the LEGO system.
- Liner
- Etch
- Gluma
- Optibond Solo Plus
Most composites are under-cured, what are 2 measures to make sure this doesn’t happen?
- Correct placement of light
- Use a finger rest
What’s wrong with curing composites with the laser system?
- Excessive polymerization strain and shrinkage
- Heat
- Composite crazing & shrinkage = sensitivity
Which light systems have narrow emission spectrums?
- Laser systems
- LED systems
How can you reduce internal stresses?
- Soft-start polymerization
- Incremental additions with C-factor
- Stress breaking liner
