Stability DEFINED AS THAT QUALITY OF DENTURE TO

Stability DEFINED AS THAT QUALITY OF DENTURE TO BE FIRM STEADY OR CONSTANT TO RESIST DISPLACEMENT BY FUNCTIONAL STRESSES AND NOT TO BE SUBJECT TO CHANGE OF POSITION WHEN FORCE ARE APPLIED. ALSO DEFINED AS THE RESISTANCE TO HORIZONTAL STRESSES

Factors affecting stability �Vertical height of the residual ridges �Quality of the soft tissue covering the residual ridge � �Quality of the impression , arrangement of teeth and the contour of polished surface

Neutral zone DEFINED AS THE POTENTIAL SPACE BETWEEN THE LIPS AND CHEEKS ON ONE SIDE AND THE TONGUE ON THE OTHER. NATURAL OR ARTIFICIAL TEETH IN THIS ZONE ARE SUBJECT TO EQUAL AND OPPOSITE FORCES FROM THE SURROUNDING MUSCULATURE

SUPPORT DEFINED AS THE RESISTANCE TO VERTICAL FORCES OF MASTICATION , OCCLUSAL FORCES AND OTHER FORCES APPLIED IN A DIRECTION TOWARDS THE DENTURE BEARING AREA

Classification of impression technique 1) BASED ON THEORIES OF IMPRESSION MAKING PRESSURE THEORY OR MUCOCOMPRESSIVE • • MINIMAL PRESSURE THEORY OR MUCOSTATIC • SELECTIVE PRESSURE • • 2) BASED ON THE POSITION OF THE MOUTH WHILE MAKING OF THE IMPRESSION • OPEN • CLOSED MOUTH TECHNIQUE

3) BASED ON THE METHOD OF MANIPULATION FOR BORDER MOLDING • HAND MANIPULATION • FUNCTIONAL MOVEMENTS