9/12: Lecture 4 - Biomaterials

Question 1

What is the most used restorative material?

Answer 1

Dental composite resin

Question 2

What are 3 components of composite resin?

Answer 2

1. Organic resin matrix
2. Inorganic filler aprticles
3. Coupling agent

Question 3

What is the organic resin matrix?

Answer 3

difunctional monomer with 2 reactive ends for cross-linking

Question 4

What are the functions of the organic resin matrix?

Answer 4

Hold composite material together, allows modality, and will polymerize when activated to harden into solid material

Question 5

What are examples of organic resin matrix?

Answer 5

Bis-GMA and UDMA
TEGDMA

Question 6

What does TEGDMA act as?

Answer 6

Dilutent and is correlated to polymerization shrinkage

Question 7

Where are the of inorganic filler particles located? What do they do there?

Answer 7

dispersed into matrix to reinforce its mechanical properties

Question 8

What are the functions of inorganic filler particles?

Answer 8

Reinforce matrix, decrease shrinkage, decrease thermal expansion, control viscosity, decrease water sorption, increase radiopacity
- different sizes and distrubutions (hybrid)

Question 9

What is the function of the coupling agnet?

Answer 9

binds filler particles to resin matrix

Question 10

What is the coupling agent made of?

Answer 10

Silane

Question 11

What does the coupling agent allow for?

Answer 11

better stress distribution, improves mechanical properties, and decreases water sorption along filler-resin interface

Question 12

What is the purpose of the activator-initiator system?

Answer 12

Monomers need to be converted to polymers

Question 13

What are activators?

Answer 13

Light (blue light)
Heat
Tertiary amine (CHEMICAL)

Mnemonic: A Loud Team, I Can’t Beat
Activators: Light and Tertiary Amine, Initiators: Camphorquinone and benzoyl peroxide

Question 14

What is the function of activators?

Answer 14

Convert initator into free radicals

Question 15

What are initators?

Answer 15

Benzoyl peroxide (CHEMICAL)
Camphorquinone (LIGHT CURED)

Mnemonic: A Loud Team, I Can’t Beat
Activators: Light and Tertiary Amine, Initiators: Camphorquinone and benzoyl peroxide

Question 16

What happens once initiators are in the free radical?

Answer 16

Addition reaction begins

Question 17

What is the purpose of bulk fill?

Answer 17

can restore in a single increment up to 4-5 mm, for posterior (class 1 and 2)

Question 18

What are the advantages of bulk fill?

Answer 18

increased depth of cure, reduced polymerization shrinkage (designed to minimize shrinkage), improved adaptation, and simplified technique

Question 19

What are disadvantages of bulk fill?

Answer 19

more translucent (body), cannot mimic layering of tooth, needs higher output in curing light

Question 20

What kind of resin matrix do bulk fills use?

Answer 20

UDMA resin matrix

Question 21

How do bulk fill composites modify their UDMA resin matrix?

Answer 21

adding aromatic groups to make it a fragmentation monomer = less polymerization shrinkage

Question 22

What initator do bulk fills use?

Answer 22

alternative photoinitiator (ivocerin)

Question 23

How does the alternative photoinitiator (ivocerin) compare to camphorquinone as an initator?

Answer 23

Alternative photoinitator has higher absorption across more wavelengths compared to camphorquinone

Question 24

What are the two types of bulk fill composites?

Answer 24

Can be flowable bulk fill (only replace dentin and acts as a base for regular composite on occlusal) or full body bulk fill (dentin and enamel, use subtractive technique)

Question 25

What are the benefits of regular composite?

Answer 25

many applications, versatile, layering technique, more esthetic

Question 26

How do the filler particles compare in regular composite?

Answer 26

More filler particles (80-85%) and usually hybrid and smaller in size