Crest has begun to revise its toothpaste ingredients after one dentist publicly voiced her concerns about a potentially dangerous component.

According to a September 15 WCPO 9 Cincinnati article, the ingredient in question, polyethylene, is a plastic found in “garbage containers, grocery bags, bulletproof vests and even knee replacements.”

Apparently, polyethylene is also responsible for the small blue flecks found in some toothpastes, especially those made by Procter and Gamble, the company that owns Crest.

When one Cincinnati dental hygienist discovered these polyethylene flakes in the gum lines of her patients, she took steps to speak out on the dangers of putting polyethylene in toothpase.

“It is used primarily for containers and packaging… and has been a concern for the environment because polyethylene lasts practically forever and isn’t biodegradable,” Trish Walraven told WCPO 9 Cincinnati. “It only breaks down into smaller and smaller particles until you can’t see it anymore.”

Not only this, but these small plastic flakes can cause gum irritation — and if they become lodged between the gums and teeth, the polyethylene flakes and microbeads can speed along gum disease and tooth decay.

According to KJRH article, Procter and Gamble is now planning to remove polyethylene from the ingredients lists of its Crest toothpastes in response to this criticism. In a statement, Crest said all polyethylene microbeads should be gone from its toothpastes by March of 2016.

Until then, it’s important to keep an eye on what toothpaste you’re putting in your mouth.