YouTube's Doctor Mike, aka Mikhail Varshavski, explains the thinking behind jaw trainers and how effective they actually are in creating a defined jawline.

So-called self-help therapies are also useful tools. Stanford says these can include daily exercises to loosen the jaw, awareness of sleep habits and education about which foods may exacerbate pain.

In TODAY.com's Expert Tip of the Day, a dentist reveals how in less than a minute, you can relax your jaw muscles with this ...