Curing / Etch / Dentine Bonding Agent

Question 1

What is light curing known as

Answer 1

Polymerisation process

Question 2

What is gel point

Answer 2

Instant where material passes from liquid to solid

Question 3

What causes stress

Answer 3

Setting up of bonding interface

Question 4

Stress relieved up to what point

Answer 4

Gel point

Question 5

After gel point, composite =

Answer 5

unyielding

Question 6

Why 2mm curing depth

Answer 6

Minimise stress transferred

Question 7

Why are fillers placed in composite

Answer 7

To decrease shrinkage

Question 8

Materials in composite

Answer 8

Strontium glass
Barium glass
Borosilicate glass
Silica
Ceramic
Prepolymerised resin
Quarts

Question 9

Etch

Answer 9

37% phosphoric acid

Question 10

Ph of etch

Answer 10

0.2 strong acid

Question 11

What occurs during etch

Answer 11

Decalcification

Question 12

How long does decalcification take

Answer 12

5-8 seconds

Question 13

What does etching do

Answer 13

Decalcifies portions of enamel rods

Question 14

Mechanism of etch on tooth

Answer 14

Dissolves calcium salts

Inter prismatic and prism areas = exposed for interlocking tag formation with bonding resin
= mechanical bonding

Question 15

Bond strength of etch

Answer 15

20mPa

Question 16

Dentine bonding agents - mode of action

Answer 16

Need to change properties of dentine (smear layer) from hydrophilic to hydrophobic

Question 17

Basic bonding to enamel/dentine =

Answer 17

Exchange process

Replacement of minerals by resin monomers

Micro mechanically interlocked in created porosity

Question 18

Dentine hybrid layer

Answer 18

Hybridisation - infiltration of resin monomers into collagen fibrillar matrix of demineralised dentine then polymerisation

Creates a molecular level mix of adhesive polymers + hard tissues = hybrid layer