You need sensitive toothpaste when it hurts to brush your teeth. People with tooth sensitivity tend to find extremes of heat, cold, sourness or sweetness of food painful, and toothpastes tend to feel cold when they hit the tooth because of the menthol in the paste. If you're having problems with your teeth hurting when you eat, a sensitive toothpaste can help reduce the pain overall.
Obviously, if you're having pain in your mouth or teeth, you should check in with your dentist. You may have a hairline crack in a tooth that's letting sensations reach the root, or your roots may be partially exposed if your gums are receding. Other causes of sensitivity may include broken fillings, cavities or gum disease. If you grind your teeth, tiny pieces of the enamel on the outside of the tooth may be flaking away, letting the layer underneath, called the dentin, become exposed to the open air. Many of these issues can be addressed with dentistry either repairing what's been broken or gone missing.
If you've been to the dentist and there's nothing requiring a dental intervention, your dentist may just tell you to use a sensitive toothpaste. Sensitive toothpaste is one of the all-too-rare over-the-counter remedies that do what they say they'll do: if you use the stuff on a regular basis, within a few days, you'll notice the discomfort lessens or even disappears. Nearly every toothpaste brand has a sensitive version, and they nearly all contain potassium nitrate, which eases the pain of the nerves in your teeth.
