A broken tooth caused by a cavity cannot be repaired with medicine; it requires professional dental treatment. You should see a dentist as soon as possible. Depending on the extent of the decay, the dentist may treat it with a filling, a crown, a root canal (if the nerve is damaged), or an extraction. Until your appointment, you can manage any pain with over-the-counter pain relievers like ibuprofen or acetaminophen. Keep the area clean by rinsing gently with warm salt water, avoid chewing on that side of your mouth, and stay away from extremely hot, cold, or sugary foods.