[Dental] impression is a -ve imprint of hard and soft tissues in the mouth, from which a +ve reproduction (cast or model) can be formed

• Placing an impression material into a stock/custom dental impression tray, which is designed to roughly fit over the dental arches
• The impression material is l iquid or semi-solid when 1st mixed and placed in the mouth, which then sets to become an elastic solid taking usually a few mins depending on the material, leaving an imprint of the Pt's dentition and surrounding structures in the oral cavity
• Adhesive, e.g. Fix Adhesive which is solvent based adhesives which increase adhesion between alginate impression amterials and the impression tray surface
• Block out wax, which can help block out undercuts prior to thermoforming

• Non-rigid materials:
  • Irreversible hydrocolloid, including [Na] alginate, which is found in brown algae, refined from brown seaweeds, e.g. Blueprint Xcreme alginate
  • Elastomeric materials, including:
    • Silicones, including:
      • PVS (polyvinyl siloxane), which is a viscous liquid that cures/solidifies into a rubber-like solid, e.g. Extrude VPS, Kulzer Activator Universal Plus, Kulzer Flexitime VPS Impression Easy Putty
      • PIP paste, which is a pure white silicone paste, used to detect areas of pressure or uneven contact on the mucosa or natural teeth from the seating of crowns, bridges, and dentures
    • Polyethers, including:
      • Vinyl Polyether, e.g. GC Fit Checker Advanced that can be used to check pressure spots and fit accuracy of prosthetic works
    • Polysulfides
• Rigid materials:
  • Zinc oxide and eugenol-based impression pastes

• Orange oil solvent, which is a lceaning solution which removes alginate or other impression materials or plasters from impression trays, hands, etc