Dentists are becoming increasingly alarmed that tiny plastic beads in many toothpaste brands can cause dental hygiene problems.

Polyethylene plastic beads are in many products -- toothpastes, face washes and body scrubs. And the Food and Drug Administration says they're safe.

But the beads are not biodegradable, and dentists are concerned that they're getting stuck in the tiny crevices between the teeth and gums.

"They'll trap bacteria in the gums which leads to gingivitis, and over time that infection moves from the gum into the bone that holds your teeth, and that becomes periodontal disease," dentist Justin Phillip told Phoenix ABC affiliate KNXV. "Periodontal disease is scary."

Crest said the beads are used only to provide color to toothpaste.

Months ago, Texas-based dental hygienist Trish Walraven sounded the alarm on her personal blog about the harm she has seen done to her patients -- and even her children. She urged her patients to stop using the products.

Crest said it has begun phasing out microbeads from its products, a process that will be completed by March 2016.

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