A video of a dog being trained to feel comfortable with having his teeth brushed has gone viral on TikTok. The clip, which has received more than 870,000 views, was posted by @sftdnyc, the TikTok ...

Accordion to VCA Animal Hospitals, over two-thirds of dogs past the age of 3 have periodontal disease, an inflammation or infection of the tissues surrounding the teeth, which is caused by plaque.

Dogs smile by pulling one or both lips back and may show all or some teeth. The "smiling" is often accompanied by other greeting behavior s, like approaching, wagging or even whining.