Adhesives 4 Flashcards
ideally, adhesives should mimic the DEJ
1) enamel
2) dentin
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Bonds to the adherent
why do we need adhesion
1) prevent leakage of bacteria and recurrent caries
2) provides seal over remaining decay
3) more conservative tooth prep
4) strengthen tooth tissue
5) bonding to enamel and dentin
6) reduce post op sensitivity
sclerotic dentin
1) dentinal tubules completely filled with minerals
2) caused by aging or caries/attrition
3) less etchable
–
1) it is built in response to caries
why worry about bond strength
1) required to overcome 17-18 mpa
2) if it shrinks and pulls away from walls, it will fail
3) needed for retention and peripheral seal
4) bonding failures are either adhesive or cohesive failure
cohesion and adhesion
1) adhesion: between bonding agent, tooth, and restoration
2) cohesion: within the same material
adhesive failure
1) interface of two surfaces
cohesive failure
1) within one surface
hybrid layer
1) a successful and long term stable bond depends on the hybrid layer with exposed collagen matrix infiltrated by resin adhesive
2) primer exposes them
- it has acid inside and the scrubbing helps
- also wets the dentin
matrix metalloproteinases
1) collagen fibril degradation
2) normally released when dentin is severed
- hydrolyze dentin bond resulting in decreased dentin bonding strength
3) MMP inhibitors: chlorohexidine and benzalkonium chloride
- added to newest bonding agent
review adhesive generations
4-7th
total etch
1) removes smear layer
2) 4th and 5th
self-etch
1) no rinse
2 incorporates smear layer
3) 6-7th
universal
1) still self etch, new additives
2) 7th
6th generation
1) acidic primer
- replaces phosphoric acid gel
- effective on dentin, not enamel
- no rinse
2) adhesive
- equivalent to adhesive in 4th gen
- hydrophobic
7th generation
1) acidic primer and adhesive
prelude
1) primer
2) adhesive
3) link
- allows for a light cured adhesive to be autocure *dualcure
- used when bonding to an opaque resin
- neutralize acidity of primer
- to cure oxygen inhibited layer of the adhesive
- not equivalent for scotchbond
3M scotchbond
1) self etch
- good bond to dentine but mediocre bond to enamel
2) selective etch preferred
3) three additional ingredients
- MDP phosphate monomer
- vitrebond copolymer
-silane
vitrebond copolymer
1) polyalkenoic acid copolymer
2) long chain organic acids from glass ionomer cements
3) provides ionic bonding to residual hydroxyapatite
silane
1) bifunctional molecules
2) bonds resin to the silica quartz filler
- organic end to resin
- silicone end to glass
10 MDP
1) 10 MDP monomer
2) bonds to many substrates
- dentin
- enamel
- metal
- ceramics
3) two functional groups that like…
- resin
- Ca2+ in tooth
- ceramic
4) long chain keeps the functional groups apart
5) phosphate group bonds to ceramic and calcium
6) methacrylate allows it to incorporate into adhesive (resin)
scotchbond uses
1) direct restorations with light
2) cementation of veneers only to thin glass ceramic
3) repair composites, PFMs, all-ceramic restorations
4) poor performance with chemical or dual cure material
tips
1) preserve enamel and dentin as much as possible
2) restore teeth using good principles of adhesive dentistry
3) understand the various generations and how their use is different
4) follow the exact correct process for each bonding system
