The document details the impression techniques and materials used in dentistry, highlighting their importance in creating dental prosthetics like dentures and crowns. It classifies impression materials into elastic and non-elastic types, including specific examples like agar, alginate, and various waxes. Additionally, it discusses the composition and characteristics of these materials, including their mixing requirements and applications in recording oral structures.

1. Name:Qaisar Abbas
Discipline:Bs Dt

2. IMPRESSION
 It is the negative imprints of the
natural teeth and their supporting
tissue.
 The impression stage is the first of
many stages involved in the
production of
dentures,crowns,bridges,orthodontic
Appliances etc.

3.  IMPRESSION MATERIAL
 Any substance and combination of substance
Used for making an impression or negative
reproduction.
 IMPRESSION TECHNIQUE
 A method used in making negative likeness.
 IMPRESSION TRAY
 A receptacle used to carry and confine plastic impres
sin material when making an impression of oral struc
tures.

4. 1)ELASTIC IMPRESSION MATERIAL
 Elastic impression material no capable of
accurately reproducing both the hard and soft
structure of the mouth.
 Classification
 Reversible hydrocolloid
AGAR
 Irreversible hydrocolloid
ALGINATE

5.  4 Main types of products from the group of
impression matrials classified as non-elastics
material.
1. Impression plaster
2. Impression compound
3. Impression waxes
4. Zinc oxide

6.  Similar in composition to the dental plaster
used to construct models and dies.
 Beta calcium sulphate hemihydrate ,when
mixed with water reacts to form calcium
sulphate dihydrate.
 Water powder ratio is very high (0.60).
 Normally used for modelling plaster.

7.  Retardar (borax)
 Anti expansion agent
 Accelerator (potasium sulphate )

8. Thermoplastic resembling
Two type;
1)Low fusing compound – green stick compound
 Medium fusing compound (impression
compound )
2)High fusing compound (tray compound )

9.  Sheets for impression of edentolous ridges
 Sticks for border extention of impression and
trays .
 For single tooth impression with copper ring
technique.

12.  Low melting paraffin wax and bees wax
 Readily flow at mouth temperature
 Soft at room temperature
 Used to record complete impression
 Used in impression of maxillo-facial defect
patient.

14.  Supplied as 2 paste system,
 White paste –base
 Blue paste-inhibator,catalyst