2-Impression-Materials.pdf

IMPRESSION MATERIALS IMPRESSION MATERIALS IMPRESSION NEGATIVE REPRODUCTION CAST POSITIVE REPRODUCTION. COPY ACCURATELY SETTING MECHANISM IRREVERSIBLE CANNOT REVERT TO ITS PRESENT STATE REVERSIBLE...

IMPRESSION MATERIALS IMPRESSION MATERIALS IMPRESSION NEGATIVE REPRODUCTION CAST POSITIVE REPRODUCTION. COPY ACCURATELY SETTING MECHANISM IRREVERSIBLE CANNOT REVERT TO ITS PRESENT STATE REVERSIBLE NO CHEMICAL CHANGE  METHODS / TYPES OF IM I. STUDY CAST FABRICATION OF THE INDIVIDUAL TRAY II. CLASSIFICATION OF IMPRESSION MATERIALS MANNER OF HARDENING THERMOPLASTIC THERMOSET CLASSIFICATION OF IMPRESSION MATERIALS DR. MCCRACKEN RIGID / INELASTIC-  CLASSIFICATION OF IMPRESSION MATERIALS ELASTIC  According to Physical Properties According to Setting Rigid/ Inelastic Elastic Reaction (edentulous patient) (dentate patient) Thermoset Plaster of Paris Alginate (irreversible) ZOE paste Rubber Impression Material Polysulfide Polyether Condensation Silicone Addition Silicone Thermoplastic Modeling compound Agar (reversible) Manner of Withdrawal Teasing movement Sudden pull parallel to from the patient’s the long axis of the mouth tooth IMPRESSION TRAYS A.STOCK TRAYS B. RIM-LOCKED TRAY C.INDIVIDUAL TRAY D.PERFORATED TRAY E. WATER-COOLED TRAY TYPES OF IMPRESSION TAKING IMPRESSION PLASTER 1) 2) 3) 4) 5) MANIPULATION MANIPULATION PROPERTIES IMPRESSION COMPOUND OTHER NAMES CLASSIFICATION MANNER OF DISPENSING: COLORS FORMS OF IMPRESSION COMPOUND IMPRESSION COMPOUND USES: a) b) c) TYPES OF IMPRESSION COMPOUND TYPE I TYPE II IMPRESSION COMPOUND: COMPONENTS  MANIPULATION: 2 WAYS TO SOFTEN IMPRESSION COMPOUND A. DRY HEAT METHOD DIRECT FLAME B. MOIST HEAT METHOD HOT WATER  DISADVANTAGES WITH THE USE OF MOIST HEAT METHOD 1) 2) TEASING METHOD  PROPERTIES OF IMPRESSION COMPOUND POOR SHRINKS 0.3-0.4% GOOD FLOW ADVANTAGE DISADVANTAGE CAST CONSTRUCTION AND SEPARATION WASH NO NEED PLASTER OF PARIS  THIN PASTE COMPLETELY OR PARTIALLY  2-PASTE SYSTEM TYPE I TYPE II USES: a) b) c) d) BASE a. ZINC OXIDE b. INERT OIL c. HYDROGENATED ROSIN REACTOR / CATALYST a) OIL OF CLOVES b) POLYMERIZED ROSIN c) ACCELERATORS d) OLIVE OIL, LINSEED OIL, COTTON SEED OIL e) CANADA BALSAM, PERU BALSAM f) FILLERS g) COLORING MATERIAL h) FLAVORING MATERIAL  OIL- IMPERVIOUS PAPER GLASS SLAB 1:1 SQUEEZE TWO ROPES SAME LENGTH FLEXIBLE STAINLESS STEEL SPATULA BROAD STROKES SWEEPING 30-45 1 MINUTE  3-5 MINUTES TEASING METHOD 1) SHORTENS DECREASES THE SETTING TIME 2) PROLONG 3) DECREASE ST 4) INCREASE ST 5) POOR CONSISTENCY AND WEAK SET MATERIAL 6) SHORTER WILL BE THE ST  NO HOT WATER 5-10 MINUTES (TYPE II, III, IV)