Composite

Question 1

3 components of composite

Answer 1

1) highly cross-linked polymeric matrix (organic)
2) fillers (inorganic)
3) silane coupling agent

Question 2

example of polymerization inhibitor

Answer 2

butylated hydroxytoluene (BHT)

Question 3

high density monomers

Answer 3

Bis-GMA

UDMA

Question 4

added to bis-GMA to decrease viscosity

Answer 4

TEGDMA

Question 5

high density makes it ___

Answer 5

viscous and difficult to manipulate

Question 6

Bis-GMA and UDMA cause increase in what?

Answer 6

increase in:

• polymerization shrinkage
• strength, rigidity
• cross linking

Question 7

the greater the proportion of diluting monomers, the greater the _____

Answer 7

the greater the polymerization shrinkage

Question 8

function of fillers

Answer 8

• reinforcement
• reduction of polymerization shrinkage
• reduction of thermal expansion/contraction
• decreased water sorption
• control of workability/viscosity
• imparting radiopacity

Question 9

quartz

Answer 9

• chemically inert
• abrasive
• hard to grind
• hard to polish

Question 10

silica

Answer 10

• not crystalline
• not as hard as quartz
• less abrasive and easier to polish

Question 11

barium

Answer 11

-most common
-radiopacity
-not as inert
slowly leached and weakened in acidity, alkalinity, oral fluids

Question 12

glass fillers

Answer 12

• attacked by fluoride solutions
• susceptible to abrasive wear
• less lifetime (compared to silica resins)

Question 13

distribution of fillers

Answer 13

various particle sizes allow max loading (fewer spaces)

Question 14

coupling agent

Answer 14

bonds filler particles to resin matrix

Question 15

commonly used coupling agent

Answer 15

organosilanes

Question 16

when would you use a microfilled composite resin

Answer 16

restoring lesions on smooth surfaces but NOT stress-bearing situations

Question 17

resin with elongated fillers and spheroidal particle fillers at different sizes (both microfine and fine)

Answer 17

hybrid composite

Question 18

better polishing than macrofilled composites, bit harder

Answer 18

small particle composites

Question 19

smaller, no surface roughing problem, better translucency

Answer 19

microfilled composite

Question 20

why do microfilled composites chip a lot

Answer 20

the bond between composite particles and cured matrix is weak

Question 21

better at high stress sites but also esthetic, contains colloidal silica and ground particles of glass with heavy metals

Answer 21

hybrid composite

Question 22

individual particles are surface coated FIRST, then put in chain
prevents agglomeration and high viscosity

Answer 22

nanofilled composite