Etch and Bond

Acid etching

the use of etchant to remove the smear layer on the tooth structure

what does etch do to teeth?

• dissolves enamel(hydroxplate crystals)

• create tags(aka undercuts) on the teeth for micro-mechanical retention

• clean/roughens the surface

• remove smear layer

micr-mechanical retention

what allows denatl materials to stick to the tooth prep

how much phosphoric acid is in etch?

37%( concentration of [30 - 40%]chem nerd stuff here 😏 )

steps for etching

1. use fluoride-free pumice to clean the surface

2. rinse + dry

3. place etch for 15 - 30 secs

4. rinse +dry( DO NOT DESICATE)

why don’t you use pumice that has fluoride?

because fluoride doesn’t work well with other bonding agents :(

what kinds of acid can etch be made up of?

malic or phosphoric acid(phosphoric is more common)

bond

glue or adhesive used to join dental materials to the tooth

hybrid layer

result of the bonding material soaking into the tooth

enamel bonding examples

• sealants

• Ortho brackets

• veneers

• MD-Bridges

what does a properly etch tooth look like?

matte; frosty white

why is dentin bonding more difficult ?

because dentin contains more live organic matter and water + more open dentinal tubercules

Side effects of etch misuse/overetching

• Enamel damage: can weaken enamel, increase likelihood of decay, leave white-spot lesions on tooth

• Tooth Sensitivity

• Tissue damage