Impression issues

dental impression failure

PVS dental impression problems

Dental impression problems will arise no matter how experienced you are or what material you use. However, with experience and knowledge the number of issues decreases significantly.

Dental impression problems that have to do with materials

These can be unavoidable. Perhaps the material was in an area of the office that is very cold and the time to set was off. Maybe there was some minor manufacturing issue. Perhaps you the dentist are trying a new material or left some bonding agent on the tooth that the impression material interacts poorly with. Some materials set at different times and mixing and matching different companies may mess with proper setting.

Image of a PVS dental impression not setting right.

Failure to set properly will likely either be a material issue or timing.

A failure of a dental impression material to set has many possible causes. Material that is bad or has expired can cause issues. Temperature plays a role as does not enough time. There are also many products that can interfere with the setting of the material, most common is bonding agent. This often occurs when dentists are experimenting with Immediate Dentinal Sealing for the first time.

Below is an example of impression material failing to set. Possible causes are too short of time, expired or poor material, cold material, impression setting inhibited by some unknown product.

Dental impression failure to set.
To see the high resolution image click here.

Chemical interaction problems

This usually is seen as a bubbling appearance in the impression materiel. Common products we see in dentistry that cause chemical interaction problems are hydrogen peroxide and the top oxygen inhibited bonding layer. Dentists that do immediate dentinal sealing will either use alcohol or glycerin and a second cure to remove the bonding layer. Hydrogen peroxide just needs a heavy rinsing.

Dental impression problems that have to do with technique or patient management

Some of these are dentist’s issues, which is a nice way of saying mistakes. Some are patient management issues that with time the dentist will learn to avoid. Timing is likely the main issue with inexperienced doctors or assistants. Every brand has a set time in which you must have the material in place or the impression will not turn out properly. Missing margins and other poor impressions will often be a combination of difficult situation and lack of experience. Poor positioning is a dentist error that will decrease with experience.

Biting on the dental impression tray

Biting on the impression tray will cause an issue and certainly will interfere with the labs ability to set the bite correctly. This is most often seen when a patient has a third molar in occlusion and they do not have much room for the tray to fit.

The images below show an impression where the patient bit on the metal tray and was not able to close all the way. The two images on the right show how you check to verify this did not occur. When you hold the impression up the light you should be able to see through it. That proves their teeth were touching. If you can not see through the impression material then you need to investigate the cause.

Dental impression problems include biting on the metal tray.

Tips to avoid and detect dental impression problems

  • Follow the instructions of your manufacturer. Don’t mix and match materials and set times. Don’t use expired materials.
  • Using higher magnification is always helpful for everything. You will be capable of seeing issues with margins with higher magnification much easier.
  • Don’t use cold material or know that if it is cold you need to let it set longer.
  • Try in your impression tray beforehand so you know it fits properly. Also have them bite together so you can see how their teeth fit.
  • If doing IDS or any bonding procedure be sure to rinse all the excess away with alcohol and rinse that with water.
  • Check the margins of the impression. Next check the other teeth near by for voids. Then check the opposing for voids and pulls.
  • Finally, hold the impression up to the light to ensure you have the patient biting.

For more information on dental impressions click the link.