If you've ever drunk a cold lemonade and felt a tingling sensation afterward, you might have sensitive teeth. Sensitive teeth develop two ways: Gum lines recede or enamel erodes. Enamel and gums act as outer shields protecting dentin, the layer beneath the enamel in your tooth. Dentin is full of tubules that lead down to your root nerves. When hot or cold food or drink contacts the dentin, your nerves erupt in pain [source: Carr].
Unlike some dental diseases related to age, tooth sensitivity can appear at any time, but most often affects those aged 25 to 30 [source: WebMD]. Not to worry. Sensitivity is curable with proper treatment and time. If your teeth don't recover after a month of good care, consult your dentist because you might have a nerve problem.
But during that month, begin self-treatment by picking the right toothpaste.