Dental Impressions

Dental Retraction Cord In Gums
©Lighthunter/Shutterstock.com

An Oral Answers reader, Austin emailed me last week with the following question:

“I had 3 temp crowns that were put in on my right side lower and 2 on my left side lower. Today when I was using my water pic I was cleaning my lower right and something started to feel like it was stuck between my teeth so I kept going and pulled out a black and white string, my gums have been bleeding and hurting.  What should I do?”

Before we talk about what happened with Austin, let’s take a look at what exactly this “black and white string” was and why it’s used in dentistry.

Dental Retraction Cord

Ultradent Ultrapak Brand Dental Retraction Cord
Dental Retraction Cord – © Ultradent Products, Inc.

Usually when dentists cut teeth for crowns, they will pack a piece of string, known as dental retraction cord, gingival retraction cord, or just dental cord between your tooth and your gums.  I’ve also used retraction cord when doing fillings on teeth that have a cavity that goes below the gum-line.

This cord helps move the gums away from the teeth and can also be treated with a solution that prevents the gums from bleeding.  That way, the dentist can focus on preparing the tooth without the gums getting in the way.  The dental cord also helps the dentist make sure that the whole tooth gets recorded when an impression is taken.

If you want to see what impression cord looks like in the mouth, scroll down to Figure 3 on this page for a picture (the dentist has prepared a tooth for a type of filling that will be made in a dental lab.)   This article has another picture of dental retraction cord.

Is Dental Cord Harmful to Your Gums?

This study looked at a few different ways to retract patients’ gum tissue and found that while dental retraction cord does cause an inflammation of the gums, they do completely heal and there is no long-term harm.  Here’s some direct quotes from the study:

  • “This study showed that all retraction techniques caused an acute injury after 1 day of retraction, which took 1 week to heal in the Ultrapak and the Magic Foam groups.”
  • “This study showed that none of the techniques tested seems to harm the tissues in the long term.”
  • “The data indicated that all retraction techniques caused a temporary inflammation, measured through the gingival index.”

In Austin’s case, it would appear that the dentist and dental assistant simply forgot to remove the retraction cord after the impression was taken and just cemented the temporary crowns on the teeth with the retraction cord in place.  If the retraction cord was in between the gums and the tooth for an extended period of time, the gum tissues may have started growing around it and it probably caused more pain and bled more when Austin removed the cord during his oral hygiene routine.

Conclusion

Although having the cord around his gums probably wasn’t very comfortable, the studies seem to show that there aren’t any long-term harmful effects.

Thanks for your question, Austin.  Hopefully you’ve helped more people know what to do if they end up finding some cord between their teeth and gums after getting their temporary crowns put on!

If you have any questions about dental retraction cord, I’d love to hear them in the comments section below.  Thanks for reading!

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Reasons Dentists Take Impressions of Your Teeth
©Milos Jubicic/Shutterstock.com

As I’ve been assisting the third and fourth-year dental students in the clinic over the past couple of years, I’ve had the opportunity of taking quite a few impressions on many different patients.

Taking an Alginate Dental Impression - Photo Courtesy of SuperWebDeveloperI think the whole impression and plaster pouring ordeal is kind of interesting.  However, many students and patients don’t seem to love it. The whole process is a bit messy.  Inevitably, the patient needs help removing the impression material that got stuck on his or her face.  Also, it leaves a bad taste in their mouths. Oddly enough, it doesn’t appear as though the man to the left is having the time of his life while his impression is being taken. So why do we take those dental impressions anyways?

Why Dentists Need to Take Impressions of Your Mouth

A dentist might need an impression of your teeth for many reasons.  A few of the more common reasons are: