adhesives

Question 1

traditional problems with bonding to detnin

Answer 1

1. low hydroxyapatite content
2. high water content
3. Bis GMA is hydrophobic
4. polymerization shrinkage of composite
5. procedure
6. technique sensitive

Question 2

effect of wet or dry dentin

Answer 2

adhesive can fill somewhat wet
it CANNOT FILL THE DRY TUBULES
-‘under-wet syndrom’
- ‘over-wet syndrome’

Question 3

solutions for dentin wet/ dry problem

Answer 3

1. dont use air for dryin - use sponge or brush
2. use desensitizer to re-wet
3. use self-etching system

Question 4

why is air drying risk

Answer 4

often leaves dentin tubules too dry and tubulues are open more – increase chances of post-operative sensitivity

Question 5

effect of dentin adhesive on moisture (MPa) with time dry

Answer 5

wet - MPa - 27

2-3 seconds dry – 13
- so loss in HALF OF BOND STRENGHT

30 seconds dry - 6 MPa

so early dentin adhesives needed moisture for bonding

Question 6

self-etching means?

Answer 6

put the etching and priming into the same step

so two components applied individually
or
two components mixed

Question 7

advantages of self etching

Answer 7

1. simpler technique – no need for moist dentin, no exposure of tubules
2. etching stage also ‘deposits’ the resin
3. reduced post operative sensitivity

Question 8

disadvantages of self etching

Answer 8

1. lower bond values to enamel
2. not compatible with self curing (or dual curing) composite systems
3. not recommended for use with resin cements

Question 9

generation 7? plus example

Answer 9

one bottle 
example is G-Bond 
1. apply and wait 10 seconds
2. air -dry  thoroughly with max air pressure for 10 deconds
3. light cure for 10 seconds

Question 10

self-cure vs light cure with composites bonded with one-bottle dentin adhesives

Answer 10

not compatible with self-cure so use LIGHT CURE WITH THESE

Question 11

How to select a good adhesive

Answer 11

1. select a product using ‘simple steps’
2. find research data to compare performance of adhesives (within the same study)
3. check shelf-life
4. ask company reps for sensitivity reports