搜了一下，這個是medical device，這是什麽意思？為什麽是醫療設備？自己可以在網上買嗎？

Fluoridated toothpaste is approved by the FDA as an over-the-counter drug for preventing dental caries. High-concentration fluoride toothpaste and other fluoride products, including fluoride varnish and silver diamine fluoride, are cleared by the FDA as medical devices for treating tooth sensitivity.