Requirements for taking impressions

Correct handling of impressions reduces the risk of distortion and increases quality

• Impressions must be taken with a proper size tray so that all the areas that need to be impressed are covered.
• After removing the impression from the mouth, make sure that it is not bitten through, that there are no inaccuracies, or that the impression material has not come loose from the tray After an intraoral scan, also check the impression file. If necessary, take a new impression immediately.
• Follow the manufacturer's instructions when handling the impression material.
• Impressions must be taken with a tray of sturdy material. Using a soft flexible tray can result in an inaccurate model and thus an inaccurate final product.
• All impressions sent to the laboratory must be cleaned of blood, saliva, food residues and adhesive. They must also be disinfected.
• Impressions must be packaged as follows:
  - alginate impressions must be wrapped in a damp napkin and placed in a plastic bag or other moisture-proof packaging;
  - the additional elements (bands, transfer posts, etc.) accompanying the impression must be placed in a separate sealable packaging.
• For fixed dental prostheses, please include the correct bite registration.
• For implant impressions:
  - the registration must be taken from the sulcus formers and the sulcus formers must be placed in a separate package with the corresponding position in the mouth marked on the package;
  - the transfers used must be without defects. If different transfers are used, please indicate the type/codes of the transfers used.
  - the transfers must be correctly encased in silicone and must not loosen inside the impression;
  - a double quantity of analogs must be included with the impression so that control models can be cast.
• For front and wax-up work, an impression/model of the initial situation must be included and portrait images of the patient must be sent by e-mail or memory stick.

Recommendations for the selection of impression materials:

• Orthodontic appliances – alginate
• Fixed prosthesis impression – silicone
• Fixed prosthesis antagonist impression – alginate
• Individual tray for complete denture – silicone
• Cast metal partial denture and flexible partial denture - alginate