Adhesion/Acid etch/Dentine bonding agents

Question 1

adhesive materials give the potential to?

Answer 1

seal vulnerable pits and fissures
conserve tooth tissue
reduce and eliminate leakage

Question 2

what are the 3 approaches to achieving adhesion?

Answer 2

micromechanical attachments
chemical adhesion to enamel and dentine
complex adhesion - wetting, penetration and formation of bound material of restorative substrate interference

Question 3

example of micromechanical attachment products?

Answer 3

acid etch

resins

Question 4

example of chemical adhesion to enamel/dentine products?

Answer 4

coupling agents

cements containing polyacids

Question 5

example of complex adhesion products?

Answer 5

modern dentine bonding agents

Question 6

a low contact angle gives?

Answer 6

good wetting

Question 7

attraction between adhesve and adhered lowers what?

Answer 7

the surface tension of adhesive = so will flow into irregularities

Question 8

acid etch for enamel margins developed by?

is the application of what?

Answer 8

Bounocore 1955

acid gel

Question 9

acid etch of enamel margins is the selective decalcification of?
creates what?

Answer 9

enamel prisms

micromechanical tags into which bonding resin may flow

Question 10

acid etch increases surface what?

Answer 10

surface roughness - microscopically

Question 11

acid etch incrases enamel surface energy by?

Answer 11

removing surface contaminants
increases wetting
facilitates micromechanical retention

Question 12

do not etch for too long or what will happen?

etch for how long to get effect?

Answer 12

too long - allows re precipitation of calcium and phosphate

10-60 seconds

Question 13

wash to etch for how long?

Answer 13

60 seconds to remove debris

Question 14

dry to allow what when etching?

Answer 14

to enable hydrophobic resin to penetrate and attach

Question 15

why stick to same manufacturer?

Answer 15

avoid potential chemical compatibility problems

avoid light curing problems especially if using LED

Question 16

what properties does an ideal dental adhesive have?

Answer 16

high bond strength to enamel and dentine
an immediate and durable bond
a reliable bond
prevent bacterial ingress
safe and simple to use

Question 17

problems with dentine bonding?

Answer 17

dentine is hydrophilic and adhesives are hydrophobics
vital
consits of organic and inorganic material
covered by a smear layer

Question 18

what are primers?

Answer 18

dentine conditioners
acids
alter surface appearance and characteristics of dentine

Question 19

what are coupling agents?

Answer 19

primers

components that do the sticking

Question 20

what are sealers?

Answer 20

flows into dentinal tubules
seals dentine with surface layer rich in methacrylates
ensures bonding to the resin in composite

Question 21

dentine conditioners - examples?

Answer 21

maleic, oxalic, phosphoric and nitric acids

Question 22

how do dentine conditioners work?

Answer 22

acid base reaction with hydroxyapatite
open dentinal tubules
demineralize surface dentine to a depth of 4 microns

Question 23

how do primers work?

Answer 23

act as adhesives
bond hydrophobic composites to hydrophilic dentine
generally - M-R-X dissolved in volatile solvent

Question 24

how does HEMA work?

Answer 24

bonds to hydroxyl of apatite and amino groups of the collagen
solvent enhances penetration by seeking and displacing water carrying the coupling agent with it

Question 25

types of sealers?

Answer 25

resins

mix of BISGMA and HEMA

Question 26

acid opening of tubules risks what?

Answer 26

nano leakage

• dentine etch is greater than resin can penetrate
• dentine microstructure disruption and failure

Question 27

3 stage process of sealing

Answer 27

1. application of etchant, washed off creating dentine demineralised layer
2. application of primer
3. application of sealer

Question 28

2 stage process of sealing - approach one

Answer 28

1 - application of etchant - washed off creating dentine demineralised layer
2 - application of primer and sealer in single solution

Question 29

2 stages of sealing - approach two

Answer 29

1 self etching primer

2 application of sealer in single solution

Question 30

one stage sealing?

Answer 30

self etching primer and sealer applied as single solution

components supplied in two pouches and mixed before use