This document discusses the principles and objectives of making dental impressions. It defines an impression as a negative copy of an oral structure used to produce a positive replica. The principles of good impressions include ensuring healthy tissues are included, borders are anatomically correct, sufficient space in the tray, and gentle removal. The five objectives of impressions are preservation of tissues, retention, esthetics, stability, and support (PRESS). Good impressions aim to maintain existing structures, resist removal forces, properly support soft tissues, and create a stable prosthesis.

1. PRINCIPLES AND
OBJECTIVES OF
IMPRESSION MAKING
DR GIRISH GALAGALI
MDS
Dept of Prosthodontics
Navodaya Dental College

2. INTRODUCTION
 The beginning of a good denture starts with
making a good impression, so a good impression
is a stepping stone for successful fabrication of
any prosthesis.

3. Definition
 Impression : a negative likeness or copy in
reverse of the surface of an object
 Dental impression : a negative imprint of an oral
structure used to produce a positive replica of the
structure to be used as a permanent record or in
the production of a dental restoration or prosthesis.

4. PRINCIPLES OF IMPRESSION MAKING
The concepts to be followed to get succesful impression
are :
1. The oral tissues must be healthy
2. Should include all of the basal seat within the limits
of health & function of supporting & limiting tissues.
3. Borders must be in harmony with the anatomical and
physiological limitation of oral structures

5. PRINCIPLES OF IMPRESSION MAKING
4. Physiological type of border moulding should be
performed
5. Sufficient space should be provided with in the
impression tray for the selected impression
material.
6. Impression must be removed from the mouth
without damaging the mucosa.
7.Selective pressure should be applied on the basal
seat during impression making.

6. OBJECTIVES OF IMPRESSION MAKING
There are 5 objectives : (PRESS)
1. Preservation – P
2. Retention - R
3. Esthetics - E
4. Stability – S
5. Support - S

7. OBJECTIVES OF IMPRESSION MAKING
PRESERVATION :
 M. M De VAN’s Dictum “It is more important to preserve
what already exists then to replace what is missing” has
ever been challenged or disapproved.
 It is physiologically accepted that with the loss of
stimulation of natural teeth the alveolar ridge will atrophy
or resorb. This process varies in individual.
 This process can be hastened or retarded by local factors.

8. OBJECTIVES OF IMPRESSION MAKING
SUPPORT :
• Denture support is the resistance to vertical forces of
mastication and to occlusal or other forces applied in a
direction towards the basal seat.
• Areas of support :
• primary
• secondary
• Slight

9. OBJECTIVES OF IMPRESSION MAKING
 Retention :
 Retention of a denture is its resistance to removal in a direction
opposite to that of its insertion.
 Retention resists the adhesivness of food, the force of gravity
and the forces associated with the opening of the jaws.
 Factors :
 Interfacial force
 Adhesion & cohesion
 Atmospheric pressure
 Gravity

10. OBJECTIVES OF IMPRESSION MAKING
STABILITY :
The stability of a denture is its ability to remain securely in
place when subjected to horizontal movements.
To be a stable denture requirres:
1. Good retention
2. Non interfering occlusion
3. Proper tooth arrangment
4. Proper orientation of the occlussal plane

11.  ESTHETICS :
 The role it in impression making refers to the development
of the labial and buccal borders so that they are not only
retentive but also support the lips and cheeks properly.