LO 4 Flashcards
(29 cards)
What restorative materials must be applied by adhesion?
- Amalgum or composite resin
- Orthodontic brackets
- Porcelain or composite veneers
How do you prepare the bonding surface (before etching)
Remove plaque, caries, and debris
______ is the first step in the bonding process
Acid etch technique
What solution is used to acid etch?
Phosphoric acid (10%-38%)
Acid etch creates _______ _______ ideal for bonding
Microscopic pores
Etching can also be called ________
Conditioning
What are resin tags?
When the resin or primer is flowed over the etched surface, it penetrates into the microscopic pores. This hardens (polymerizes), it creates projections called resin tags
What is micromechanical retention?
When resin tags lock into the tooth, it creates a mechanical bond know as micromechanical retention
Bonding agents are usually ______ viscosity
Low
Good wetting encourages ________
Better contact
When etching enamel, it reduces the ends of ________
Enamel rods
When etching enamel, resin tags are created in and around
The enamel rods
Etched enamel appears ______
Frosty
What should you take into consideration when etching dentin?
- Higher water content
- Collagen matrix with fewer minerals
Dental tubules in dentin causes ______
Fluids to flow from the pulp
Define hydroxyapatite
Cut tooth structure (from drilling cavity)
What is the smear layer and why does it need to be removed?
- A tenacious surface layer of debris resulting from cutting the tooth during cavity prep. It is composed of mostly fine particles of cut tooth structure and can contain saliva, blood, bacteria, and plaque
- Sticks to dentin and plugs dentinal tubule openings, greatly reducing permeability. It also interferes with formation of bond to dentin
What is used to remove the smear layer?
Phosphoric acid
How long does etching take?
Approx 60 seconds
What does timing for etching depend on?
- Manufacturer directions
- Area being etched
- Strength of phosphoric acid
Rinse time is ______ compared to etch time
Equal
During the etching process, it is important that dentin is not _______
Dessicated (overdried)
When bonding to enamel there is/are ______ component(s)
One (bonding agent)
When bonding to dentin there is/are ________ component(s)
Two (primer and adhesive/bonding agent)