Acid Etching for Enamel and Dentin Bonding Flashcards
Know compositions of Enamel and Dentin
- Mineral/Inorganic
- Organic
- Water
Enamel: 88-M, 2-O, 10-W
Dentin: 50-M, 25-O, 25-W
3 Jobs etching accomplishes
- Dissolves hydroxy apatite
- Removes smear layer
- Increases total surface energy
What is the % of phosphoric acid used for enamel etching?
30 - 40%
Does increasing the depth of demineralization increase bond strength?
NO! It will actually increase post-op sensitivity!
Degree or _______ varies enormously from acid to acid and from patient to patient
decalcification
TERM – used to improve estheritcs because it makes the visual transition from tooth to composite more gradual
Easier to hide finish lines if they are VERTICAL and HORIZONTAL rather than diagonal
Bevels
How long should you etch primary teeth?
60 - 120 seconds
Etching enamel for as little as _____ seconds produces the same bond strength as etching for longer
15 seconds
If you over etch dentin, bond strength will —?
DECREASE
Dentin is a ____ bonding to enamel?
Secondary
6 Steps of Bonding to Enamel
- Shade selection prior to RD isolation
- Place bevel and remove unsupported enamel
- Etch enamel
- Rinse and Dry
- Place enamel bonding resin (NO SCRUB)
- Place restorative composite
After enamel has been etched, saliva _______ the bond strength to enamel
DECREASES
How must you treat a contaminated etched tooth?
RE-ETCHING
Does GI require etching?
NO -Chemical bonding between:
- Polycarboxylic/ Phosphate monomers
- Hydroxyapatite
5 Steps for Bonding to Dentin
- Etch dentin for 15 seconds (NO MORE)
- Rinse and Dry (not overdrying)
- Place dentin/enamel bonding resin
- Scrub bonding resin (unlike enamel)
- Place restorative composite
True/ False
Water will contaminate etched enamel
False!
Saliva and Blood will contaminate etched enamel!
Properties of Dentin
- Contributes ___ % to the hardness of enamel
- _____ tensile strength and _____ modulus of elasticity than enamel
- ________ properties
- Stops the propagation of _______ in the enamel
- 20%
- higher tensile strength and lower modulus of elasticity
- isotropic properties
- most cracks
Is dentin uniformly mineralized?
NO
Which is more mineralized – peritubular or intertubular dentin?
Peritubular Dentin
Tubule density changes with _____?
location
Dentin relies on the penetration of adhesive monomers into ______ fibers
Collagen
In order to create microtags in enamel, you should etch with strong or weak acid?
STRONG
You should etch dentin with a strong or weak acid?
WEAK
The type of class # with the highest C factor =
Class I
Is composite packable and condensable like amalgam?
NO
TERM—
- Adheres to layer of tooth debris, saliva, and bacteria
- Covers surface and plugs tubules to reduce permeability
- Weak cohesion and adhesion (limits bond strengths)
SMEAR LAYER
If dentin becomes dessicated, ____% of the bond strength is lost
50%
How can you restore the bond strength if dentin is dessicated?
Rehydrate with water to open the collagen fibers prior to the next step of the restoration
Does a composite resin fight against caries if leaking occurs?
NO
Should a tooth be wet or dry when diagnosing caries?
DRY
What allows for the composite restoration to able to add another layer or composite? (unless contaminated with blood or saliva)
Oxygen Inhibition Layer
Is it necessary to redo the whole composite if you find a void with an explorer post curing?
NO- simply use bond and composite to patch the void
Does self-etching primers remove the smear layer?
NO- there will be a hybrid and smear layer entanglement
Does total etch remove the smear layer?
Yes! A hybrid layer entanglement will occur with resin adhesive
The bonding agent will penetrate thru the __________ dentin and forms the hybrid layer (resin-dentin interdiffusion zone)
Intertubular Dentin
Greater # of blades on a bur = smooth/rough cutting?
Smoother
If a patient is at high risk for root caries, what restoration material should be considered?
Glass Ionomer
When polishing a composite, you should begin with the ______ to ______ abrasive disks
Coarse to fine
True or False?
Silicane is the nano filler particle
FALSE– fillers are glass particles
Is using color the best indication for determining caries?
NO – arrested caries are darker than active caries; staining
When polishing a composite with a rotary instrument, it is important to keep in mind that it results in….
1.
2.
- Heavy Force
- Heat Production
What was the initial dentin bonding system like?
3 step system
- Strong acid
- Primer scrubbed into dentin
- Resin adhesive, thinned, and polymerized with light
True or False
The 3 step dentin bonding system is technique sensitive
TRUE; however it is the GOLD STANDARD!
Primers are solutions containing ______ monomers dissolved in a solvent such as acetone, ethanol or water.
Hydrophilic
In order to simplify the 3 step dentin etching system… What 2 components were added together to create a 2 step system?
- Acidic Etch
- Primer and Bonding Agent
What components are part of the optibond solo plus?
- Primer
- Bond
2-Step dentin etch technique (with use of acid etch first)
How exactly does dessicating the dentin prevent the bonding integrity?
- Collagen bridges collapse
- Poor penetration of primer/bond
- Unhealthy hybrid layer
Describe how to use the optibond solo plus
- Apply primer/bond
- Scrub for 15sec on all areas of tooth needing bonding
- Blow air to thin
- Repeat steps 1-3
- Light cure for 20 seconds
What is the purpose of using 2 layers of primer/bond?
- Improve penetration
- Thicker hybrid layer
- Increases bonding agent coverage and strength
Thoughts about One-Step Self-etch?
BAD
Several challenges with all 3 components were combined into one bottle.
Dental Composite setting reaction is a ______-______-_______ setting reaction
Free-Radical-Initiating Setting Reaction
The oxygen inhibition layer consists of many ______ monomers which allow for the continuation of added composite if needed.
Uncured (non-polymerized resin)
