Bonding

Question 1

Discuss Bonding to Enamel

Answer 1

Bonding to enamel is easy
High mineral content, can be demineralised by etch
Low water content helps

Question 2

Discuss Bonding to Dentine

Answer 2

Harder because of greater organic content

Dentine has lower CSE than composite

Question 3

Requirements of a Dentine Bonding agent

Answer 3

Flowability
Intimate contact with Dentine
Low viscosity
Adhesion to substrate

Question 4

Critical surface energy is lower in Dentine than in composite so

1. What happens to composite if it is applied
2. How to fix this

Answer 4

1. It slips off and doesn’t bond

2. Prime the Dentine to increase the CSE

Question 5

Discuss Dentine Conditioner

Answer 5

• 37% orthophosphoric acid
• removes smear plugs from smear layer on Dentine
• causes decalcification and exposure of collagenous matrix

Question 6

Discuss Dentine Primer

Answer 6

• HEMA
• bifunctional
  hydrophilic (HE) bonds to Dentine
  hydrophobic (MA) bonds to composite

Question 7

Discuss Bond

Answer 7

Resin that penetrates Dentine surface and attaches to primers hydrophobic surface

Usually a mixture of bis-GMA and HEMA