Resin Composites

Question 1

What is a resin composite?

Answer 1

a combination of 2 chemically different materials with a distinct interface separating the components.

Question 2

What are resin composited used for?

Answer 2

tooth coloured fillings

Question 3

What is the earliest direct tooth coloured restorative material called?

Answer 3

Forerunner’s silicates

Question 4

What is the setting reaction of forerunners silicates?

Answer 4

aluminosilicate glass + phosphoric acid = salt and water

Question 5

Where are acrylics derived from?

Answer 5

products used to make dentures

Question 6

What type of set do acrylics have?

Answer 6

chemical

Question 7

In resin composite, what is the resin matrix usually based upon?

Answer 7

methyl methacrylate or dimethacrylate monomers

Question 8

What are the 3 components of the resin matrix?

Answer 8

• Methacrylate/ dimethacrylate monomer
• Comonomers i.e., TEGMA
• Inhibitors

Question 9

What reaction occurs in retained acrylics in resin composites?

Answer 9

free radical polymerisation

Question 10

What is polymerisation triggered by?

Answer 10

light curing

Question 11

What do fillers have to be coupled with?

Answer 11

coupling agent

Question 12

What are coupling agents used for?

Answer 12

improve the adherence of resin to filler surface

Question 13

What is the purpose of fillers?

Answer 13

reduce shrinkage

Question 14

What is the name of the coupling agent in resin composites?

Answer 14

vinylsilate

Question 15

What is silane?

Answer 15

a filler

Question 16

What happens to surface hardness as filler content increases?

Answer 16

surface hardness increased

Question 17

What happens to volume when filler is added?

Answer 17

decreases percentage volume by setting

Question 18

What happens to thermal expansion when filler is added?

Answer 18

thermal expansion decreases

Question 19

What is the visible blue light used to set resin composites called?

Answer 19

camphorquinone

Question 20

What do all resin composites contain?

Answer 20

resin
filler
coupling agent

Question 21

What are resin and filler useless without?

Answer 21

coupling agent

Question 22

What is the role of coupling agent?

Answer 22

transfers the stress generates under loading from the rigid and brittle filler to the more flexible and ductile polymer matrix

Question 23

What are the 4 types of resin composites based on filler particle size?

Answer 23

• conventional
• microfilled
• hybrid
• nanocomposites

Question 24

What must the properties of resin composite conform to?

Answer 24

ISO 4049

Question 25

What happens to viscosity on leaving the tube?

Answer 25

increases

Question 26

What are the disadvantages of resin composite?

Answer 26

may stain as resin matrix can take up fluids e.g., wine

Question 27

What influences the overall success of a restoration?

Answer 27

cavity shape

Question 28

What is C factor?

Answer 28

number of bonded surfaces/ number of un-bonded surfaces

Question 29

What does C factor relate to?

Answer 29

shrinkage

Question 30

What type of setting occurs in resin composite?

Answer 30

exothermic

Question 31

What can trapped air pockets in resin composite result in?

Answer 31

inhibition of polymerisation and softens the matrix

Question 32

What are nanofillers?

Answer 32

fillers with particle sizes ranging from 1-1nm

Question 33

What is the optimum absorption of camphorquinone?

Answer 33

460-480nm

Question 34

What happens when composite cures?

Answer 34

contraction

Question 35

What are the 3 mechanisms influences by chemical effects?

Answer 35

• abrasive
• erosive
• fatigue

Question 36

What is the name of the coupling agent?

Answer 36

vinylsilane