Dental Materials: An In-Depth Exploration of Bonding and Bonding Agents

What is bonding?

means of binding two adjoining materials and providing resistance to their separation

3 multiple choice options

What are the three essential functions of a dental bonding system?

- provides resistance to separation

- distributes stress along bonded interfaces

- seals interface

What is adhesion?

molecular or atomic attractions between 2 contacting surfaces promoted by interfacial force of attraction btw. molecules/atoms of 2 different species

3 multiple choice options

How is adhesion achieved between teeth?

- removing hydroxyapatite to create pores

- infiltration of resin monomers into micropores and subsequent polymerization

What are factors that play a role in adhesion bond formation? .

- surface energy and wetting

- interpenetration

- micromechanical interlocking

- chemical bonding

- hydrolytic stability

What is the the smear layer?

poorly adherent layer of ground dentin produced by cutting the surface of dentin

3 multiple choice options

Application of ___ is used to remove the smear layer from both enamel and dentin

acid

True/False: older patients who have been exposed to fluoride longer will need a longer etch time

True

What is the etching time for most etching gels?

A) 10 seconds

B) 15 seconds

C) 30 seconds

D) 1 minute

B) 15 seconds

True/False: the advantage of short etching times is that they yield acceptable bond strength

True

How long should the acid be rinsed off the tooth for?

A) 10 seconds

B) 20 seconds

C) 30 seconds

D) 40 seconds

B) 20 seconds

True/False: dentin can withstand aggressive drying after being etched

False

True/False: aggressive drying of dentin causes collapse of the dentinal tubules

True

True/False: contamination increases the energy level of the etched surface

False

What is the most widely used type of acid for etching?

phosphoric acid

What percentage of phosphoric acid works best on enamel?

A) 15%

B) 23%

C) 37%

D) 52%

C) 37%

Dentin cannot be aggressively dried after acid etching BECAUSE it causes the collapse of the dentinal tubules

A) statement true, reason true, related

B) statement true, reason false, unrelated

C) statement false, reason false

D) statement true, reason true, unrelated

A) statement true, reason true, related

Phosphoric acid removes the smear layer and about ___ microns of enamel

A) 5

B) 10

C) 15

D) 20

B) 10

Phosphoric acid removes about ___ microns of enamel

A) 5

B) 10

C) 15

D) 20

B) 10

What is an example of a bonding agent?

BISGMA

True/False: BISGMA is a liquid at room temp

False

I. BISGMA is a paste at room temperature

II. BISGMA won't flow into etched crevices

A) I true, II false

B) I true, II true

C) I false, II false

D) I false, II true

B) I true, II true

What is used with BISGMA to bond to the tooth?

TEGDMA

True/False: TEGDMA is paste at room temperature

False

What is the proper process of etching a tooth?

- etch enamel for 15 seconds

- rinse (15-20 seconds)

- dry enamel

- place adhesive

- light cure for 20 seconds

- place restorative material

Place these steps in the correct order:

1. rinse (15-20 seconds)

2. place adhesive

3. light cure 20 seconds

4. etch enamel (15 seconds)

5. place restorative material

6. dry enamel

A) 1, 2, 3, 4, 5, 6

B) 4, 1, 6, 2, 3, 5

C) 4, 1, 6, 5, 3, 2

D) 3, 1, 4, 2, 5, 6

B) 4, 1, 6, 2, 3, 5

___ MPa is deemed necessary to eliminate leakage

A) 17

B) 23

C) 33

D) 37

B) 23

True/False: a bevel increases surface area and creates more micromechanical retention

True

True/False: you should always etch a tooth 2 mm beyond the finishing line

True

What are the 3 steps to bond to dentin?

- etch + rinse/dry

- prime

- place adhesive

True/False: if you overetch dentin, you can cause postoperative sensitivity

True

What are ways to prevent dentin collapse after an etch and rinse?

- air syringe 1-3 seconds

- blot with a damp cotton pellet

What are the three components of dentin bonding agents?

- acid

- primer

- adhesive

What is a primer?

molecule that makes a moist hydrophilic surface more hydrophobic so the hydrophobic adhesive will spread out on it

3 multiple choice options

Etchants have a pH around

A) 1-2

B) 3-4

C) 5-6

D) 7-8

A) 1-2

What is an example of a primer using in dentin bonding agents?

HEMA

True/False: HEMA has high hydrophobicity

False

True/False: if a primer has the ability to both etch and prime, it is categorized as a self-etching primer

True

What are most commonly used solvents in dentin bonding agents?

water, ethanol, acetone

What is the primary purpose of using adhesives?

fill interfibrillar space of the collagen network

What are the types of polymerization?

- photoinitiator

- self-cure

- dual cure

What is an example of a desensitizer that reduces post-op sensitivity?

glutaraldehyde

2 multiple choice options

What is added to prevent collagen degradation?

benzalkonium chloride and chlorhexidine

2 multiple choice options

What is the composition of the hybrid layer?

collagen, HEMA, BISGMA

All of the following are components of the hybrid layer EXCEPT one. Which one is the exception?

A) collagen

B) fibrillin

C) HEMA

D) BISGMA

E) none of the above

B) fibrillin

The hybrid layer is around ___ microns thick

A) 10

B) 15

C) 20

D) 25

A) 10

The fourth generation of bonding agents is

A) 1 step

B) 2 steps

C) 3 steps

D) 4 steps

C) 3 steps

The fifth generation of bonding agents is

A) 1 step

B) 2 steps

C) 3 steps

D) 4 steps

B) 2 steps

The sixth generation of bonding agents is

A) 1 step

B) 2 steps

C) 3 steps

D) 4 steps

B) 2 steps

The seventh generation of bonding agents is

A) 1 step

B) 2 steps

C) 3 steps

D) 4 steps

A) 1 step

What are common bonding errors?

- contamination of field

- desiccated dentin (collapse + poor infiltration)

- over etch results in demineralized collagen under hybrid layer

True/False: if there is saliva contamination after etching, you should rinse, re-etch for 10 seconds, rinse and proceed

True

If you have saliva contamination, you should:

A) rinse, re-etch, rinse, and proceed

B) start over

A) rinse, re-etch, rinse, and proceed

If you have blood contamination, you should

A) rinse, re-etch, rinse, and proceed

B) start over