impression material
DESCRIPTION
Impression Material. IMPRESSION MATERIALS, TYPES and TRAYS. Impression are negative reproduction of teeth and surrounding structure Preliminary Impression done by the assistant poor dimensional stability stock impressions trays Final Impressions done by the doctor only - PowerPoint PPT PresentationTRANSCRIPT
Impression Material
IMPRESSION MATERIALS, TYPES and TRAYSImpression are negative reproduction of
teeth and surrounding structurePreliminary Impression
◦done by the assistant◦poor dimensional stability◦stock impressions trays
Final Impressions◦done by the doctor only◦good dimensional stability◦stock impressions trays /custom trays
Preliminary Impression Material◦Irreversible Hydrocolloid/Alginate◦Thermo-dots◦Polyvinylsiloxane Condensation
materialUses:
◦Diagnostic models◦Opposing arch models◦Fabrication of custom trays◦Fabrication of provisional
restorations
IMPRESSION TRAYSFull arch
◦custom made◦preformed plastic◦perforated rim
lock◦max/mand
Quadrant◦custom made◦preformed plastic ◦perforated rim
lock
Triple Tray◦quadrant◦sextant◦take upper and
lower in oneSextant Tray
◦custom made ◦preformed plastic◦perforated rim
lock◦ant/post
INITIAL IMPRESSIONSNegative is poured
in gypsum to create a positive model.
Models can be articulated together, articulator recreates the TMJ.
Models can be used as opposing for bite registration
FINAL IMPRESSIONSNegatives poured in
gypsum to create positive model
Models are articulated together and the prep tooth is cut out of the model to create a die
A die is a replication of the prepared tooth or teeth or the edentulous mouth
CUSTOM TRAYSAcrylic light cured or self cured
resin material◦need a polymer and monomer◦polymerization = setting
CUSTOM TRAYSVacuum formed custom trays
◦resin sheets are heated and formed over the initial impression using heat and vacuum
CUSTOM TRAYSThermoplastic tray material
◦beads or buttons that are pliable when heated
Preformed rim lockLocks impression material into
tray
Preformed Plastic Need tray
adhesive
Triple TraysTakes final impression, opposing
impression, and bite registration
CUSTOM TRAYSAcrylic resin trayMuch like the
thermoplastic beads
Needs spacer and stops because of the custom fit
Spacer can be pink wax, aluminum foil or wax paper
ELASTOMERIC MATERIALSRubberlike qualitiesUsed when precise duplication is
neededNo distortion, great dimensional
stabilitySupplied in a two paste system
◦base and catalystSupplied in either a two tube system
or extruder gunCan be one or multiple body types
Polysulfide ◦ Advantages good stability,accuracy sharpness in detail light = syringe, wash
medium, heavy = tray material
long shelf life used for crown, bridge,
partial, denture impressions
◦ Disadvantages stains, tastes bad and
stinks ten minute setting
time
Polyether◦ Advantages
excellent accuracy great dimensional
stability medium body only,
used as both syringe and tray material
used for crown, bridge, denture and partial impressions
◦ Disadvantages only one body type
Silicone◦ Polysiloxane
Condensation – putty
used for bite registration, custom tray
◦ Polyvinylsiloxane addition silicone advantages
high degree of accuracy and dimensional stabilty
three body types disadvantages
expensive
Bite Registration◦ Polysiloxane bite
registration material open bite (shown) closed bite
◦ Wax bite registration material pink wax horseshoe wax bees wax aluwax
Preparation for ImpressionSelect materialSelect type of
tray or traysObtain an
opposing arch, if necessary
Apply adhesive as directed to impression tray
Mix syringe material, deliver to provider
Mix tray material, place in tray and deliver to provider
Remove impression. disinfect and evaluate
Prepare provisional if necessary
What to send to LabLab slipFinal ImpressionOpposing archBite registration
◦ It is important to give the lab tech everything they will need to produce a quality product
Deliver AppointmentProsthetic should be due two
days before appointment. Any adjustments can be done
outside the mouth before cementation or placement
Final adjustment of cemented appliance can be done in the mouth
Oral hygiene instructions