Celebrities smile for photos, during live performances, and in TikToks. But what's hiding behind those gleaming grins? In some cases, unexpected (and potentially harmful) oral health mistakes .

To be fair, some of their habits aren't as bad as avoiding the dentist. (About 100 million people in the United States don't visit their dentist annually, according to Colgate .) However, many of their unusual oral health and hygiene behaviors can lead to unwanted tooth or whole-mouth consequences.

Take the brushing routine of Julia Roberts, for instance. Her so-called "megawatt" smile has been one of her most notable traits for decades (via Popsugar ). But her choice of daily toothpaste additive — baking soda — draws a frown from some experts. Though baking soda is definitely an ingredient

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