Types of Impression Materials:

Inelastic Impression Materials

1. Plaster (same properties as gypsum)

2. Wax (cheap , clean , easy to use much like paraffin or others like Play-doh)

3. Impression compound - wax with added filler to improve stability)

4. Zinc oxide-eugenol (ZOE) (set to a hard and brittle mass)

Types of Impression Materials:

Aqueous Elastomeric Impression Materials

1. Alginate or also called (irreversible hydrocolloid will not reverse to the sol state once they react)-major component is water) - chemical reaction. Liquid state: sol, semisolid, rubbery state called the gel. The SOL state:foam

Not so accurate

Composition: -Potassium alginate (carbohydrate polymer)

derived from algae

-Filler (diatomaceous earth (silica)

Hydrophilic

Temperature of the water controls the rate of the setting reaction.

Remove impression after 2-3 min

2. Agar (reversible hydrocolloid) - physical change. Reverse back when heated, and than back to gel state when cooled. Premixed by manufacturer supplied as a semisolid material in tubes and sticks.

Composition: carbohydrate polymer + water + colorants + sulfate compound (for hardness)

Tampering - when reversible hydrocolloid placed in 110ºF (45ºC) warm water bath, lowering the tº comfortable for oral tissues.

Hysteresis - the characteristics of melting and gelling at different temperatures. (unlike water melts & freezes)

Non-aqueous Elastomeric Impression materials:

1. Polysulfides

2. Condensation Silicone

3. Polyethers

4. Addition silicons

1.Name Irreversible hydrocolloid?

2.What is major compound?

3. Liquid state term?

4.Sol state term?

5. Composition? - ...from algae+ filler ?

6.Term for having tendency to mix, dissolve with water?

7.What kind of reaction?

8. What controls the rate of the setting reaction?

1. Alginate or also called (irreversible hydrocolloid will not reverse to the sol state once they react)-

2. major component is water) -

7. chemical reaction. 3. Liquid state: sol, semisolid, rubbery state called the gel.

4.The SOL state:foam

Not so accurate

5. Composition: -Potassium alginate (carbohydrate polymer)

derived from algae

-Filler (diatomaceous earth (silica)

6. Hydrophilic

8.Temperature of the water controls the rate of the setting reaction.

Remove impression after 2-3 min

1. Name reversible hydrocolloid?

2. Chemical reaction or physical change?

3. Composition?

4. What is tampering?

5. What is Hysteresis ?

1. Agar (reversible hydrocolloid)

2. - physical change. Reverse back when heated, and than back to gel state when cooled. Premixed by manufacturer supplied as a semisolid material in tubes and sticks.

3. Composition: carbohydrate polymer + water + colorants + sulfate compound (for hardness)

4. Tampering - when reversible hydrocolloid placed in 110ºF (45ºC) warm water bath, lowering the tº comfortable for oral tissues.

5. Hysteresis - the characteristics of melting and gelling at different temperatures. (unlike water melts & freezes)

1. Name impression material which is : - non-aqueous elastomeric "rubber"

2. Sets by which reaction?

3. Supplied in?

4. Consist two parts- name them? explain which base made of?

5. Which agent promotes polymerization reaction?

6. Which impressions more accurate polysulfide or alginate?

7. What is advantage of polysulfide impression?

8. which factore conributes to setting time?

1. Polysulfide

2. Polysulfide materials sets via a condensation polymerization reaction. "Condensation" polymerization is based on the production of water.

3. 2 pastes in tubes (typically brown and white)

4. white "base"-sulfide polymer mixed with inorganic filler titanium oxide.

brown "accelerator" paste contain lead oxide and oily substance and

5. sulfur which promotes polymerization reaction.

6.Polysulfide impressions more accurate than alginate, but not like other non-aqueous elastomeric materials.

7. they have the longest working time of any elastomeric materials.

8. accelerated by heat and humidity 

1. Name elastomeric material based on silicone rubber?

2. Hydrophobic or hydrophilic?

1.  Condensation silicone

2. Hydrophobic

1. Name impression material which sets by cationic polymerization?

2. Properties:?

3. Name most popular polyether product?

1. Polyether

2. -setting time is shorter than polysulfide materials

- very stiff

- sets quickly

- have unpleasant taste

-very accurate

3. Impregum

1.  Name most popular elastomeric impression materials, which don't have unpleasant taste, most accurate, stable and expensive?

2. What is other names of ....?

3. Which polymerization reaction occurs?

1. Addition silicone

2. -vinyl polysiloxanes 

- polyvinylsiloxanes

3. polymerization occurs by way of free radicals and addition polymerization.