A two step impression is when an impression is taken twice, the first time with heavy/medium body, then when that material is set, the second step is to add light body over the VPS putty for another impression.
Below is a video and step by step instructions on how to take two-step impressions.
Download a printable guide to taking two-step impressions here.
- Two impression trays
- Tray adhesive
- Light body impression material
- Impression gun
- VPS putty
- Small square of plastic wrap
- Scissors (for cutting end of light body tip)
Ensure that you have the right size tray for the patient's mouth. The tray should extend beyond the last tooth in the arch without touching the gums.
When you’re sure you have the right size trays for your patient’s mouth, apply adhesive to the trays. This will help prevent the impression material from becoming unseated from the tray upon removal from the mouth.
Mix the VPS putty. Set your timer for the working time of your material, then knead the two putties together until you get a mixture that has no streaks in it.
When the putty is thoroughly mixed, roll the mixture up into a "sausage" and fit it into the tray.
Place the square sheet of plastic wrap over the tray and press into it gently to make a shallow channel in the putty.
Making sure the tongue and lips are out of the way, press the tray firmly into the teeth. Set your timer for the intra-oral set time of your putty. Wait for the putty to set, then take the tray out and remove the plastic wrap.
Express the light body impression material into the indentations in the tray - you don't need a lot.
Press the tray into the teeth, but not too hard - you don't want the teeth to push all the way through the impression material and touch the tray. Set your timer for the intra-oral set time of your light body material, and keep pressure on the tray until the impression has set.
When you're checking your impression for quality, make sure that:
- All teeth are clearly registered
- There are no voids or tears
- At least 5mm of gum tissue is visible
- No teeth are hitting the tray