Tech tip: The anatomy of a good impression

A high-quality impression is the foundation of a successful case. Whether for a submission or a revision, accurate impressions are vital to ensuring that treatment is effective and time-wasting delays are avoided. 

We've listed our guidelines for a good impression below. Follow along and view an example of an excellent impression on our printable guide:

Detailed, accurate occlusal surfaces.

A clear impression of the occlusal surfaces ensures that the aligners will have a tight fit.

  • Sharp cusps

  • Tray doesn't show through impression

All gingival margins are defined and clear.

Defined gingival margins ensure enough retention points are present for effective tooth movements.

  • Includes about 2mm of buccal and lingual surfaces outside gingival margin

Distal surfaces of molars are captured.

This is a common cause of missing retention points and fitting issues during phase 0. If your patient has short clinical crowns, getting a clear impression of the molars is especially important.

  • More than half of each molar is visible

Impression material is intact.

Damaged or thin impression material compromise the accuracy of the molds and resulting aligners.

  • No damage, warping, or separation of light and heavy material

No imperfections in the impression material that compromise dental anatomy.

Imperfections or double imprints in the impressions could affect the effectiveness of treatment with the resulting aligners.

  • No bubbles, voids, thin walls, shifts, or double imprints

More Helpful Tips:

  • Make sure the tray is not too small and fits your patient well. If the teeth are touching the edges of the tray, the tray is too small.
  • Use plenty of PVS material. It's better to have too much than too little.
  • Remove all engagers prior to taking the impression. We need impressions free of attachments to make accuracte molds.
  • Fill in black triangles with wax. This will allow you to remove the material cleanly without creating pulls or distortions.
  • Refrain from moving the material as it sets. We recommend waiting an additional 60-90 seconds longer than instructed before removing the trays from the patient's mouth.
  • Don't forget the light body material! Add the light body before the putty or heavy body dries completely.


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