Impression materials
Any substance or combination of substances used to record an impression or negative reproduction those are called as impression materials.
Impression technique
A method and manner used in making a negative likeness.
Classification
1. Based on material use
A. Inelastic or rigid
- Impression plaster
- Zinc oxide eugenol
- Compound wax
B. Elastic
-
- Alginate
-
- Polysulphide
-
- Silicone
-
- Polyether
-
- Elastomers
- Agar
2. Based on setting of materials
A. Chemical reaction
- POP
- ZnOE
- Alginate
- Silicone
B. Physical change
- Agar-agar
3. Based on viscosity
A. Mucostatic
- Impression plaster
- Agar
- Light body elastomer
B. Mucosuppressive
- Impression compound
- Alginate
C. Pseudo-plastic
- Addition silicone
4. Based on interaction with water
A. Hydrophobic
- Polysulphide
- Addition silicone
B. Hydrophilic
- Putty impression plaster
5. Based on use
A. Primary impression materials
- Impression compound
- Alginate
B. Secondary impression materials
- ZnOE
- Medium body elastomers
C. Duplicating materials
- Agar