Common Dental impression mistakes - impression taken by a dentist

The Most Common Dental Impression Mistakes & How to Avoid Them

We’ve all heard the saying “You never get a second chance to make a first impression.” When it comes to dentistry, that phrase ought to be “You never want to need to make a second impression.”

Although the use of digital intraoral scanners can help avoid many of the problems associated with impressions, traditional methods are still commonly used.

They’re not always easy to get right, but with the right combination of knowledge and experience, your patients will have the smile they deserve.

Let’s take a look at some of the most common dental impression mistakes for fixed prosthetics, and what you can do to avoid them.

Margin Detail

One of the most common problems that lab technicians deal with is inadequate marginal details. This is the most important aspect of the impression, and you should take extra care to get the best results possible.

Most often, margin errors result from inadequate retraction or fluid accumulation.  Poor margin detail will likely lead to open margins or prosthetics that don’t fit as they should.

For these reasons, try using syringeable hemostatics to reduce the chances of such errors.

Material Mixing Mistakes

Properly mixed materials will display a consistent color and texture and lack any streaking.

If you are using cartridge materials, make sure you bleed the cartridge before attaching the tip. This will allow the catalyst and base to flow uniformly.

Also, you should never use tray materials and wash from different providers. Even slight variations from company to company will lead to a less consistent result.


Whether a result of blood, water or saliva, trapped fluids will create bubbles in the impression.

When this happens, the luting agent can become compromised as a result of having to cover a larger area.

Similarly, the prosthetic material might become thinned. Both of these problems result in a less-than-ideal fit.

Problems Inherent with the Tray

Tray selection matters, and this is true regardless of whether the tray is a single or dual arch.

It must be large enough to ensure all the teeth are captured, while also not coming into contact with any soft tissue.

One that is too small is certain to miss the needed arch detail. Choose the right sized tray for the job, and avoid this problem.


Drags or Pulls in the Impression

Drags or pulls result when problems associated with the use of viscous materials arise.

Drags are a byproduct of depressions being left in the impression material when the tray is inserted, and they often can’t be repaired simply by adding more material.

Pulls result when extraneous material creates a fold – most often at the gingival aspect.

Should the need arise, you can usually correct a pull by removing the interproximal impression material, which then allows for the impression to be reinserted.

To help avoid both drags and pulls, take care and be gentle when you’re inserting and removing the impression tray.


Although less frequently evident, contamination can’t be ignored in the discussion about errors relating to fixed prosthetics.

You should always keep in mind that rubbing alcohol alleviates the potential for contamination, and it ought to be used on the tooth/teeth and the impression.

Gloves also can transfer contaminants, so you’ll want to make sure you’re using powder-free or vinyl gloves.

The Twitchy Patient

This last item might be the most frustrating.

Why? Because it’s the one you have the least amount of control over.

Whether it’s because of nervousness or a strong gag reflex, if your patient cannot remain still, these movements can lead to problems.

Dentists are encouraged to use their best TLC practices when patient unease arises. It might be as simple as reminding patients that they’re perfectly safe, or explaining the importance of staying motionless.

Be polite and courteous, but do your best to calm them down and relax them. 

most common dental impression mistakes - bringing it all together

Even though IOS scans are becoming the standard in dentistry, you might still side with traditional impressions.

It’s easy to make mistakes without the right guidance, but you can avoid them more often than not if you know what to look for in each situation.

Follow these strategies to get the best results, and to give your patients a reason to smile! If you have any questions or need support with your impressions during the process, we’re here to help. Just complete the form on this page and we’ll guide you to a better impression!

About First Choice Dental Lab

First Choice Dental Lab is a full-service dental lab with locations in Downers Grove, Il. & Wauwatosa, Wi.

We manufacture & customize quality dental restorations for general dentists. We create smiles based on your needs and budget.

We’re here to help you give your patients a reason to smile!

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