Zinc oxide eugenol impression pastes

Question 1

Two paste system

Answer 1

Base paste- Zinc oxide
Accelerator- Eugenol

Question 2

Composition

Answer 2

**Base paste (white) **
- Zinc oxide 87%
- Olive oil, Linseed oil
- Zinc acetate
- Traces of water

Accelerator (red)
- Eugenol
- Fillers (Kaolin, Tale)

Question 3

Applications of ZOE paste

Answer 3

Insulating medium in tooth cavities (cementing)
Temporary filling material (sedative)
Root canal filling material
Promotes healing (surgical pack)
Corrective impression material
Bite registration paste
Relining material for loose dentures

Question 4

Setting reaction

Answer 4

Sets by chelation (acid+base) = (salt+water)
1. Zinc oxide+water = zinc hydroxide
2. Zinc hydroxide (base) + Eugenol (acid) = Zinc Eugenolate

Question 5

Slowing down setting time

Answer 5

• Add small glycerine
• Alter amount of paste
• Cooling mixing slab

Question 6

Advantages and disadvantages

Answer 6

**Advantages **
- Good consistency
- Dimensional stability
- Sufficient working time
- Records accuarte details
-No separation medium needed as no reaction with gypsum
-Correctable
Most mucostatic paste

**Disadvantages **
-Requires special tray for manipulation
-Sticky
-Eugenol gives a burning sensation
Inelastic terefore cannot be used in undercuts