In a dental digital era, talking about PVS impressions may sound like something from the past. However, many of us started our Invisalign journey taking PVS impressions and we have all felt overwhelmed about rejected impressions at some point.
For those colleagues who do not have an intraoral scanner, here are my tips for taking PVS impressions for Invisalign:
Use high-quality PVS dental material
Align Technology recommends the use of PVS dental materials that comply with ISO specification 4823 and/or ADA specification 19. Some recommended materials are: Aquasil or Aquasil Ultra, Pentamix or Dimension
Technique and materials recommended
Use the technique that you are most comfortable with – the ultimate goal is to get a good impression.
- Single step (Single step (PVS heavy body and medium body) or
- Two steps (PVS heavy body and medium body or PVS heavy body and light body).
Remember, always respect the manufacturer’s recommended time to avoid elongated teeth. If a two-step technique is being used, before adding the light body in the tray inject some material on the occlusal surfaces and bleed the cartridge. Keep the tip submerged when filling the tray to avoid air bubbles in that area.
Remember to use vinyl, nitrile or powder-free latex gloves and Invisalign trays. Never use metal trays since the impressions sent are scanned and the metal will impede the scanning process.
Review the impressions taken before sending
Check that all the teeth are visible in the impression and 1 – 2mm of gingiva has been captured.
Retake the impression in case any of the following issues is present:
If you are unsure about distortions present in the impression, take and send 2 impressions. This will allow the technician to choose the better one and may help them if digital detailing is required.
Article by Dr Daniela Ramirez Guevara