Restorations

Question 1

What is the most ideal wettability of a resin?

Answer 1

Needs to be wettable.
Lowest degrees possible.

Question 2

Define the following categories of wettability in degrees:

Mostly non-wetting

Absolutely no wetting

Mostly wetting

Absolute wetting

Answer 2

Categories of wettability include:

“mostly nonwetting” (>90 degrees),

“absolutely no wetting” (180 degrees),

“mostly wetting” (<90 degrees),

and absolute wetting (0 degrees).

Anusavice, Kenneth J.; Shen, Chiayi; Rawls, H. Ralph. Phillips’ Science of Dental Materials - E-Book (Anusavice Phillip’s Science of Dental Materials) (p. 259). Elsevier Health Sciences. Kindle Edition.

Question 3

Can wettablity be enhanced by increasing or decreasing the surface energy of the surface (ie. dentin, enamel)?

Answer 3

Wettability can be enhanced by INCREASING the surface energy of the substrate.

Question 4

How is surface energy increased?

Answer 4

Surface energy of a surface can be increased by cleaning and microroughening the tooth. This is done with cleaning and acid etching the surface.

Question 5

What is hydrolytic stability and why is it important?

Answer 5

Hydrolytic stability is the resistance to chemical degradation by water. Enamel and dentin are hydrated, hydrophilic a nd permeable to water. For an adhesive monomer to wet hard tooth tissue, it must be both HYDROPHILIC for water compatiblity and HYDROLYTICALLY STABLE to ensure longevity.

Question 6

Why must dentin not be completely dry when applying a hydrophobic resin?

Answer 6

Because the collegen fibers (mainly type I) will collapse.

Question 7

What does contamination such as saliva, blood or oil do to the surface energy of a surface?

Answer 7

Contaminants will REDUCE surface energy and REDUCE wettability. If a surface becomes contaminated – etch it again for 10 seconds.

Question 8

How long should an etchant be placed? How long should it be rinsed?

Answer 8

Etch for 15 s (generally) and rinse for 20s

Question 9

What is the pH of etchants?

Answer 9

pH 1-2

Question 10

What are the main components of a bonding system?

Answer 10

A typical dentin bonding system includes etchants, resin monomers, solvents, initiators and inhibitors, fillers,

Anusavice, Kenneth J.; Shen, Chiayi; Rawls, H. Ralph. Phillips’ Science of Dental Materials - E-Book (Anusavice Phillip’s Science of Dental Materials) (p. 262). Elsevier Health Sciences. Kindle Edition.

Question 11

Describe the steps for the following (state how many steps there are to each):

Fourth generation bonding systems.

Fifth generation bonding systems

Sixth generation bonding systems

Seventh generation bonding systems

Answer 11

Fourth generation bonding systems: 3 step (etch; prime; bond)

Fifth generation bonding systems: 2 step (etch; prime & bond is in one)

Sixth generation bonding systems: 2 step (etch&prime is in one; bond is 2nd step)

Seventh generation bonding systems: 1 step (etch prime & bond all one step)

Question 12

What are the following compounds?

bis-GMA, TEGDMA, and urethane dimethacrylates (UDMA),

Answer 12

These are the mostly hydrophobic adhesive resins in most dentin bonding systems

Question 13

True or false:

Methacrylamides have recently replaced methacylates in several resin bonding products because it is more hydrolytically stable.

Answer 13

True

Question 14

What are the three ways polymerization can be initiated in both adhesives and restorative composites?

Answer 14

Polymerization can be initiated through :

• a photoinitiator system (ie. camphorquinone) and an initiator (ie. tertiary amine)
• through a self cure system that includes a chemical initiator (ie. benzoyl peroxide)
• through a dual-cure initator system