The Most Common Impression Mistakes- And How to Solve Them!

Putting an impression tray in your mouth and hoping for the best can be daunting, no matter how many times you have read the instructions. But never fear, we are here to help you make a good impression!

Here are the most common mistakes made in an impression, and what you can do to solve them.

1- Back Molars not Captured

The most common problem that impressions may have is not quite getting the back molars. What that means is that though we can see your back molars on the impression, they are not in all the way. Usually, this is because the gum line that goes all the way around the impression comes down to meet the last tooth, instead of continuing past it the way it does in this example.

The best way to make sure your back molars are all the way in like this picture, is to apply pressure with your thumbs on the backs of the trays when you push the tray onto your teeth. Then, leave your thumbs there for the whole 3 & 1/2 minutes that the tray is in your mouth.

2- Teeth Scraping Through Putty

If your teeth scrape through the putty so that the tray is showing, the impression would not be approved. Check carefully for any places where your teeth went through the putty, and if you find any, give us a call.

3- Teeth Against Tray Wall, or Shallow Putty In Between

Another aspect of the impressions that sometimes contributes to the back teeth not being deep enough is the teeth being too close to the inner or outer wall of the tray. If the impression of a tooth is right next to the wall, without any putty in between, or even very thin or shallow putty, it is not capturing that tooth.

When you try the tray in your mouth without any putty, make sure that your teeth have plenty of room.

If your teeth are up against the walls of the tray on both sides of your mouth, call us, and we can recommend a different tray size.

Make sure you are spreading the putty out as evenly as possible.

4- Drag Marks

If a drag mark is impairing the impression of any of the teeth or breaking up the gum line, it would not work. Drag marks can be caused by several factors.

If there is a drag mark behind the back molar, make sure the tray is completely off of your teeth before pulling it out of your mouth next time.

If you are finding drag marks on your front teeth, focus on the way you are taking the tray out of your mouth on the next one. Don’t pull the tray out by the handle. Instead, pull the sides straight down.

It could also be a timing issue, so make sure you are leaving the tray on your teeth for no less than 3 and a half minutes.

If you are not sure if your impressions are workable, feel free to take a photo and send it to We will let you know how you can solve any problems and make a good impression.