Tooth decay is the primary cause of toothaches for most children and adults. Bacteria that live in your mouth thrive on the sugars and starches in the food you eat. These bacteria form a sticky plaque that clings to the surface of your teeth.
Acids produced by the bacteria in plaque can eat through the hard, white coating on the outside of your teeth (enamel), creating a cavity. The first sign of decay may be a sensation of pain when you eat something sweet, very cold or very hot. Sometimes decay will show as a brown or white spot on the tooth.
Other causes of a toothache can include:
An accumulation of food and debris between your teeth, especially if your teeth have spaces between them
Inflammation or infection at the root of the tooth or in the gums
Trauma to the tooth, including injury or grinding your teeth
Sudden fracture of the tooth or tooth root
A split in the tooth that occurs over time
Teeth that start to appear (erupt) through the gums, such as with teething or wisdom teeth that don't have enough room to emerge or develop normally (impacted wisdom teeth)
A sinus infection that can be felt as pain in the teeth
A toothache often requires some sort of treatment by your dentist.
Until you can see your dentist, try these self-care tips for a toothache:
Rinse your mouth with warm water.
Use dental floss to remove any food particles or plaque wedged between your teeth.
Consider taking an over-the-counter (OTC) pain reliever to dull the ache, but don't place aspirin or another painkiller directly against your gums because it may burn your gum tissue.
If the toothache is caused by trauma to the tooth, apply a cold compress to the outside of your cheek.
Use caution with products containing benzocaine
Previous advice included sparingly applying an OTC antiseptic containing benzocaine directly to the irritated tooth and gum for temporary relief. But benzocaine has been linked to a rare and serious, sometimes deadly, condition called methemoglobinemia, which decreases the amount of oxygen that the blood can carry. So follow these guidelines:
Talk to your dentist or doctor before using an OTC antiseptic containing benzocaine.
Don't use any products that contain benzocaine — such as teething gels with benzocaine (Anbesol, Orabase, Orajel, others) — in children younger than 2 years old.
Never use more than the recommended dose of benzocaine.
Store products containing benzocaine out of the reach of children.