Lecture 4

Question 1

benefits of composite resins

Answer 1

good aesthetics, easy to place and cured by light

Question 2

what are the components of composites?

Answer 2

organic resin and inorganic filler w/ coupling agent interface

Question 3

benefits of resin/filler?

Answer 3

resin: : helps w/ processing and handling
filler: holds modulus in place and resists wear

Question 4

probs of resin / filler?

Answer 4

resin: poor wear resistance
filler: brittle and poor processing

Question 5

how do you cure composites?

Answer 5

crosslinking w/ light

Question 6

crosslinking holds ____ chains togther w/ _____ bonds and crosslink _____ depends on starting materials

Answer 6

polymer
covalent
density

Question 7

different sizes of filler

Answer 7

micron, nano and nano in matrix

Question 8

traits of nano fillers

Answer 8

have high SA so high viscosity also have tendency to aggregate, fill up to 40%

Question 9

traits of microfillers

Answer 9

80% fill

Question 10

traits of nano fillers in matrix

Answer 10

don’t aggregate but dont have coupling agent so poorer matrix bonding, fill 60%

Question 11

benefits of smaller fillers(like nano)

Answer 11

high polishability and wear resistance

Question 12

consequences of shrinkage

Answer 12

stress on tooth structure and microleakage leading to 2’ caries

Question 13

components of glass ionomer

Answer 13

acid-polymer in aq. solution

base- glass

Question 14

how are glass ionomers cured?

Answer 14

acid base rxn., the stronger the acid, the faster and more exothermic

Question 15

when curing glass ionomers, you get the fomation of ______, not all _____ is consumed, no _______ _______ is needed, and _____ is slowly released

Answer 15

salt bridges
glass
coupling agent
fluoride

Question 16

differences and similarities btwn adhesives and composites

Answer 16

adhesives still have resin chem and are light cured but they have acidic groups and are unfilled

Question 17

the ______ properties of adhesives let them bind to composite and the _______ properties let them bind to enamel

Answer 17

hydrophobic

hydrophilic

Question 18

what do hydrophilic modifiers do?

Answer 18

promote bonding

Question 19

how are sealants different from composites?

Answer 19

no filler, and low viscosity

Question 20

what’s the oxygen inhibition layer?

Answer 20

layer where ox. interferes with radical polymerization -prob w/ sealants b/c they’re so thin