Operative Final Review

Question 1

Which generation of dentin bonding agents is the gold standard?

Answer 1

4th Gen - Etch, prime, bond (Optibond FL)

Question 2

What are shortcomings of 7th gen dentin bonding agents?

Answer 2

1. Lower durability, Increases water sorption in HEMA rich adhesives, and phase separation of adhesive components with HEMA, increased nanoleakage, reduced shelf life

Question 3

What are the benefits of wet bonding for total etch?

Answer 3

1. Increased resin-dentin bond strengths

2. Decreased post-sensitivity

Question 4

Why the addition of water for etching adhesives? (wet bonding)

Answer 4

Decreases the sensitivity associated with dry bonding

Question 5

Why do etchants contain water?

Answer 5

To ionize the acidic reaction

Question 6

How does the strength of an acid in self-etching adhesives affect the bond?

Answer 6

The stronger the acid etch component, the greater the penetration of the resin tags into the smear layer and then into dentin.

Question 7

Define hybrid layer

Answer 7

Resin-dentin inter diffusion zone

Question 8

Which generation is considered the strongest and most durable?

Answer 8

6th gen (self etch, etch/prime and then bond)

Question 9

What are the three methods of adhesion?

Answer 9

1. Physical (van der waals, electrostatic interaction)
2. Chemical (bonds between atoms)
3. Mechanical (undercuts and irregularities produce interlocking of material)

Question 10

Does tubule density increase or decrease as you go from enamel to dentin to pulp

Answer 10

Tubule density decreases as you move away from the pulp

Question 11

What is the pH and hybrid layer thickness of phosphoric acid?

Answer 11

pH 0.1-0.4

Depth: 5-8 um

Question 12

What is the pH and hybrid layer thickness of ultra mild SE?

Answer 12

pH >2.5

Depth: 300 nm

Question 13

pH and hybrid layer thickness of Mild SE

Answer 13

pH = 2

Depth: 500 nm - 1 um

Question 14

pH and hybrid layer thickness of strong SE

Answer 14

pH < or equal to 1

Depth: 4 um

Question 15

What pH is best for etchant?

Answer 15

Mild and 2.0

Question 16

Explain “water tree formation”

Answer 16

Poorly hybridized resin tags are saturated with water as opposed to hybridized resin tags in etched dentin saturated with ethanol. This prevents sealing of the hybrid layer

Question 17

Define microleakage

Answer 17

Passage of bacteria and toxins between restorative margins and tooth prep walls

Question 18

Define nanoleakage

Answer 18

Microporosities in the hybrid layer and dentin

Question 19

What is an MMP and how are they activated?

Answer 19

Matrix Metalloproteinase Protein - slowly degrade exposed collagen fibrils
- Activated by acid etching

Question 20

Should CHX be used to inhibit MMP’s in vivo? Why is this?

Answer 20

No, no difference between groups in terms of sensitivity or clinical performance of composite restorations. This is because CHX is water soluble and will wash out over time.

Question 21

Particle size of macro filled?

Particle size of midi

Answer 21

10-100 um

1-10 um

Question 22

Particle size of mini
Particle size of Micro
Particle size of Nano

Answer 22

0. 1 to 1 um
1. 01 to 0.1 um
2. 001 to 0.01 um

Question 23

Difference between heterogenous and hybrid

Answer 23

Heterogenous are mixtures of cured and uncured composites that are all the same size. Hybrid has a mixture of major particle sizes

Question 24

Greatest degree of conversion for composites?

Answer 24

65%

Question 25

What is the depth of cure for A1-A2 shades?

Answer 25

5 mm

Question 26

What is C factor?

Answer 26

Number of bonded vs unbounded surfaces

Question 27

What is the significance of placing composite margins on dentin vs enamel?

Answer 27

Tredwin study concluded that all dentin margins showed significant more leakage then enamel margins in every combination. Gingival margins should be placed on enamel.

Question 28

Composite contraction stress

Answer 28

17 MPa

Question 29

Filtek bulk fill depth of cure and indications?

Answer 29

Depth: 4 mm

Indicated as base for Class I and II, more shrinkage, less CTE due to lower filled content

Question 30

Percentages between hydrogen peroxide and carbamide peroxide

Answer 30

Hydrogen peroxide: 38% (in office)

Carbamide peroxide: 10% (home)

Question 31

Non-vital bleaching technique

Answer 31

“Walking bleaching” - Uses sodium perborate (38%) - may cause cervical external resorption. Stay above CEJ

Question 32

If patient is asymptomiatc, how much can you bleach?

Answer 32

As much as you/they want

Question 33

Indications/contraindications of bleaching

Answer 33

Indications: Pt not happy with color esthetics
Contraindications: Hypersensitivity, pregnant and lactating women, children with large pulps, gingival recession, finances

Question 34

What is in Gluma and how does it work?

Answer 34

Gluteraldehyde and HEMA - precipitates plasma proteins to occlude dentinal tubules . Can interfere with dentin bonding systems (because you’re occluding the tubules)

Question 35

What kind of fillers are added to hybrid composites?

Answer 35

Surface modified zirconia/silica and surface modified silica particles

Question 36

What kind of filler particles are added to Filtek supreme?

Answer 36

20 nm Silica filler, 4-11 nm zirconia filler, and combined 20 nm silica and 4-11 nm zirconia/silica cluster filler

Question 37

What kind of filler particles to Filtek bulk fill flowable?

Answer 37

0.1 to 5.0 um ytterbium trifluoride filler and 0.01 to 3.5 zirconia/silica.