Dental hygienist Trish Walraven began noticing tiny pieces of plastic embedded in her patient's gums on a daily basis at her Dallas, Texas-based practice. The tiny bits of plastic were embedded in her patients' sulcus, a gum channel that acts as a protectant against diseases like gingivitis.
The sulcus is a band of tissue that's similar to the cuticles along your fingernails, preventing foreign objects from entering your gums, according to Walraven's blog Dental Buzz.
Crest's decorative plastic beads get stuck in your gum line
"We thought it was maybe a cleaning product or something that people were chewing," Walraven said to CBS affiliate WISH-TV.
Recent reports have revealed that the source of these tiny pieces of plastic is Crest toothpaste. At least 19 different Crest brands carry the plastic microbeads, which the company alleges is for decoration only, a marketing tactic designed to give the toothpaste an extra pizzazz. Kids particularly love it.
According to Crest's website, the microbeads are made from polyethylene, a common commercial polymer widely used in plastics. In early March, Walraven made note of Crest's only mention of polyethylene, which stated that the ingredient was added to paste for color, not as a cleaning agent that would help remove plaque or prevent cavities; however, the link was later removed on Sept. 9. Walraven suspected that this might happen, so she kept a copy of the page, which you can view here.
"In theory, if these particles are trapped in the gingival sulcus, sort of the space between the tooth and the gum tissue, it could act as an irritant. I don't know of any studies that support that," said Dr. Domenick Zero, the Director of Oral Health Research at the Indiana University School of Dentistry.
Polyethylene is used to make bulletproof vests, grocery bags and knee replacements. Because it's low in cost and resistant to moisture, the government used it for high-frequency radar cables during World War II. Even worse, it's hardly biodegradable, remaining in nature for long periods of time. New York and California are taking steps toward banning the microbeads from personal care products and cosmetics.
Not even alcohol dissolves Crest's microbeads
After discovering the product's source, Walraven ran to her bathroom cabinet to check whether her family had any Crest toothpaste in the house. Sure enough, her daughter was using toothpaste containing polyethylene that was decorated with colorful packaging likely meant to attract kids.
After squeezing a pea-sized amount, the dental hygienist cleverly mixed the sample with some water, straining out the particles. Then she dried them and added two household solvents to the samples separately to test their dissolvability. Even after leaving the samples in the solutions overnight, neither acetone nor alcohol made any changes to the plastic particles.
Her at-home experiment shed light on why the plastic bits weren't dissolving in people's mouths but instead getting stuck in their gums.
"Polyethylene will not dissolve in the mouth, or even in household products. It is an inert substance, which means that it doesn't change at all," she said.
Crest was quick to point out that the use of microbeads has received federal approval by the U.S. Food and Drug Administration; however, the company still plans to remove the plastic from their products by March 2015.