Composite material

Question 1

Resin modified GIs, GI

Answer 1

hydrophobic (water based)
self-adhesive
no adhesive required

Question 2

Compomers, Composite resin

Answer 2

hydrophobic (resin based)

Not self adhesive - requires adhesive

Question 3

Dental composite matrix phase

Answer 3

continuous phase

• monomer resin
• initiators

Question 4

dental composite dispersed phase

Answer 4

discontinuous phase

• glass fillers
• colorants

Question 5

Monomer functional groups

Answer 5

monomethacrylates

dimethacrylates

Question 6

monomethacrylates

Answer 6

linear chains - soft - can melt easily

Question 7

dimethacrylates

Answer 7

branched and crosslinked - rigid, don’t melt easily.

Question 8

Composite monomers

Answer 8

difunctional methacrylates

form highly crosslinked rigid networks

Question 9

Monomers in composite

Answer 9

potentially estrogenic - tegma, BIS-GMA, TEGDMA

Question 10

Silicate glasses influence

Answer 10

strengthen (rule of mixtures, more filler = more strength)
Optical properties (color, translucency)
Radiopacity

Question 11

Filler surface

Answer 11

glass has hydrophilic surface

• silica tetrahedrons
• surface hydroxyl groups
• attract water molecules
• inhibits wetting of surface with monomers (hydrophobic)

Question 12

Silane coupling agent

Answer 12

silane coupler - gets hyrophilic glass into composite

• improve composite properties
• adheres filler to resin phase
• primer
• MPS

Question 13

Abrasive

Answer 13

non-contact wear - foods abrade polymer

Question 14

Attrition

Answer 14

occlusal contact wear - higher stresses, lead to polymer microfracture

Question 15

Improved wear from

Answer 15

smaller, softer particles

Question 16

Crystalline (original) filler

Answer 16

quartz - radiolucent, very hard and abrasive

Question 17

Non-crystaline (glasses)

Answer 17

modified to improve characteristics

-softer, additives to make glass radiopaque, more crushable, need to have it wear with resin**

Question 18

GI

Answer 18

acid base rxn

Question 19

Composites

Answer 19

free radical rxn

Question 20

Dentin as substrate

Answer 20

initial preps likely to encounter tubular dentin

Question 21

Smear layer inhibits good adhesion

Answer 21

ground bits of HA, collagen, bacteria, salivary proteins Inhibits resin penetration into dentin

Question 22

Etchant

Answer 22

inorganic acid - 35% Phosphoric acid
completely remove smear layer and plugs
demineralizes surface dentin
leaves a collagen rich surface with numerous pores

Question 23

Primer

Answer 23

primarily hydrophilic monomers - water, alcohol, acetone barrier

Question 24

Adhesive

Answer 24

hydrophilic/hydrophobic mix

Question 25

Hybrid layer

Answer 25

interdiffusion zone - resin and collagen

interpenetration zone

Question 26

Curing lights

Answer 26

halogen
plasma arc lights
argon lasers
LED (the norm)

Question 27

LEDs

Answer 27

peak output ideal for CQ. Power intensity similar to highest QTH but lower than laser and xenon arc

Question 28

LED curing units

Answer 28

small, compact and light weight
battery powered and cordless
long bulb life
power output narrow (negative)
Tip design limited (negative)

Question 29

Curing composite

Answer 29

degree of conversion - % double bonds converted, usually 65%

Depth of cure - 1mm = 65%, 2mm = 45%, 3mm to 4 mm = 15%.

Question 30

Light intensity is proportional to the

Answer 30

distance squared.

Question 31

Acute angle symbol

Answer 31

starts low ends high

Question 32

sun symbol

Answer 32

high output light - faster overall.