Ever wonder why, when you're feeling under the weather, your teeth seem to be especially sensitive to pain? It has to do, unsurprisingly, with your mouth.

Cracked teeth can also cause cold sensitivity. Small fractures or stress lines can open slightly under pressure, allowing cold liquids to reach the dentin and pulp. Because cracks may be invisible ...

A new study reveals that the sensitivity of teeth, which makes them zing in a dentist's chair or ache after biting into something cold, can be traced back to the exoskeletons of ancient, armored fish.