Resin Composites 2

Question 1

what is the optimum absorption of camphorquinone?

Answer 1

460-480nm = visible blue light

Question 2

what kind of activation lights have been used in the past?

Answer 2

-quartz tungsten halogen GTH
-fibre optic light guide - on use fibres break, reduced efficiency for light transmissions
- cooling/timing mechanisms
heat
broad spec filtered to eliminate harmful wavelengths

Question 3

LED’ s = what kind of spectrum?
have a low?
what kind of heat?
bulky or small?

Answer 3

narrow spectrum
less bulky
low heat
low current

Question 4

avoid what with LED’s?

Answer 4

sequential activations

Question 5

what is LED quality control like?

Answer 5

low

Question 6

how to increase coverage with LED lights?

Answer 6

multi LED curing lights

Question 7

Zach and Cohen 1965 found?

Answer 7

5. 5 degrees caused pulipitis in 15% monkey teeth

11. 1degrees caused pulipitis in 60%

Question 8

with an LED unit wait how long until using again?

Answer 8

at least 30 seconds before curing again

if not = heat builds up at LED tip = discomfort and tissue irritation

Question 9

Plasma Arcs - xenon bulbs how do they work?

Answer 9

spark, potential difference across gas and gas ionises to form plasma

Question 10

plasma arcs - how much power output?

what do they need?

Answer 10

ten times QTH

need efficient cooling

Question 11

apply plasma arc for how long?

was stops sequential activations?

Answer 11

2-3 seconds

timer prevents sequential activations

Question 12

Argon lasers give out?

Answer 12

blue light

Question 13

Argon lasers narrow wavelength means?

Answer 13

do not coincide with all materials

Question 14

Argon lasers have a collimated beam which allow?

Answer 14

greater depth cure with minimum heat production

Question 15

how to look after a unit?

Answer 15

avoid contact with RC

regularly check the output

Question 16

How to use a lamp checker?

Answer 16

apply to light from new because measurements are relative

Question 17

what is abrasive wear?

Answer 17

hard asperites penetrate the polymer matrix removing material by shearing and cutting

Question 18

what is erosive wear?

Answer 18

impact of asperites produce damage of polymer matrix

Question 19

what is fatigue?

Answer 19

Localised deformities of polymer = subject to repeated stresses = failure

Question 20

In vitro staining by silver staining can see what 3 stages of wear?

Answer 20

• little wear, no substance damage
• higher wear, more considerable damage
• catastrophic wear b/c extensive subsurface damage

Question 21

what is resin matrix softening?

Answer 21

Inhibition of polymerisation b/c entrapped air pockets

b/c chem scattering = foods, plaque acids

Question 22

stress concentrates at resin filler and what happens?

Answer 22

thermomechanical fatigue
watersorption
polymerisation shrinkage
mechanical stresses on restoration