Lec 3 Bonding, Etching, Primer Flashcards
The process of attaching restorative materials, such as a bonded amalgam or a bonded composite resin, to the tooth by adhesion.
Bonding
The first step in the bonding process involves ___________ of the surface of the tooth or the ____________ to receive the material that will be bonded to it.
preparation; restoration
Conditioning the enamel or dentin with an acid.
Etching
Most commonly used acid is ____________ in concentrations ranging from ___________.
- phosphoric acid
- 10% to 38%
Removes mineral from the surface to create roughness.
Acid
Are usually applied with a brush, a small cotton pellet, or a small sponge.
Liquid etchants
Are usually applied by brush or dispensed from a syringe through a fine needle or brush tip.
Gel etchants
- The recommended rinsing time for acid gels is approximately _________ or longer.
- Rinsing times _____________ may not remove residual silica.
- 10 seconds
- shorten than 5 seconds
Rinsing times for liquid etchants can be shorter— ______ seconds.
5 to 10 seconds.
Surface Wetting
- ______________ creates a high surface energy.
- ____________ attracts contaminants and resin to the etched surface.
- Surface must be _________ if saliva contamination occurs.
- ___________ increases contact of the bonding resin with etched tooth structure.
- Acid etching
- High surface energy
- re-etched
- Good wetting
Enamel etching was introduced by?
Dr. Michael Buonocore (1950s)
Affects the prism core or prism periphery or both.
Enamel etching
Acid Solution affect the prismatic structure of the enamel by preferential removal of either? (3)
- prism core
- prism periphery
- both
An etched enamel surface as seen in this scanning electron micrograph has numerous ___________ that provide __________ and greatly increase the ___________ for bonding.
peaks and valleys
retention
surface area
Etching pattern characterized by removal of prism core.
Type I
Etching pattern showing loss of prism periphery.
Type II
“honeycomb” appearance
Type I etching pattern
Enamel rods etched, creating numerous _____________.
microundercuts
Resin bonding agent engaging microundercuts, creating ___________ for mechanical bond to tooth.
“resin tags”
Etching Times:
- Enamel of permanent teeth is etched for ___________.
- The etched surface should have a __________ when dried.
- Primary teeth should be etched for __________ or more.
- 20-30 seconds
- frosty appearance
- 60 seconds
When a cavity preparation is cut with rotary or hand instruments, this layer of cutting debris forms on the surface of the cut dentin and enamel.
Smear layer
Dentin etching:
- Etching dentin with phosphoric acid dissolves the _________ first, then portions of the _____________ from the surface of the dentin, creating a _________ surface and exposing _____________ that are part of the dentin matrix.
- Dentin is etched for ______________.
- When one is etching both enamel and dentin as in a coronal cavity preparation, it is best to apply the acid to the _________ first for 10 seconds, then to the ________ for 10 seconds.
- _____________ dentin can result in a weaker bond and in posttreatment sensitivity.
- smear layer; hydroxyapatite crystals; porous surface; collagen fibrils
- 10 seconds
- enamel; dentin
- Over-etching
Removes some of the mineral exposing the collagen fibers of the matrix, as seen in this scanning electron micrograph.
Acid etching of the dentin
3 types of etching technique?
- self-etch
- selective etch
- total etch
