A brown spot on your tooth can be unsettling. How can you tell if you have a cavity or a stain?

Is it a stain or a cavity?
Sometimes simple behaviors such as drinking dark-colored beverages may slowly stain teeth over time and cause brown spots or yellowing of teeth. Other common causes of tooth stains are using tobacco, aging, some medications, overusing fluoride and a buildup of plaque or tartar on the teeth. Most of the time, teeth stains cover the entire tooth instead of a single spot and will appear and disappear quickly.

Cavities are holes in teeth that grow larger over time. They may be caused by poor oral health care or eating foods high in sugar. Most of the time, it's easy to tell a cavity from a stain due to the uncomfortable side effects of cavities. However, there are some situations where it is hard to tell the difference, especially when a cavity is small.

Spots on your teeth that are black, brown or gray may indicate a cavity. However, there are many other symptoms that indicate if a spot is a cavity:
 
  • Visible holes in the teeth. If you notice a hole in your tooth, it's a cavity.
  • Tooth pain. Cavities may start off causing only slight pain and become more severe. Pain caused by a cavity can radiate to other parts of your body, including the jaw and ears. Any tooth pain should be evaluated by a dentist.
  • New sensitivity. If drinking an ice-cold beverage or biting into hot food makes you squirm, it could be a sign that you have a cavity. This is because the tooth enamel is breaking down and can expose sensitive parts of your teeth.
 
How to treat stains on your teeth
Stains on teeth can usually be treated with at-home treatments:
 
  • Reduce or eliminate stain-causing foods or beverages.
  • Increase the number of times you brush throughout the day, especially after consuming stain-causing foods and drinks.
  • Try at-home whitening treatments.
 
If you have trouble removing a stain or notice that it's growing in size, schedule an appointment with your dentist because it may be a cavity.

How to treat a cavity
Unlike stains, cavities must always be treated by a dentist. Your dentist will treat a cavity in one of the following ways:
 
  • Filling: Getting a filling is the most common way a cavity is treated. Your dentist will remove damaged parts of the tooth and fill it with resin that matches the tooth color.
  • Dental crown: In some cases, a cavity destroys enough of the tooth that it can no longer be fixed with just a filling. Dental crowns are artificial teeth that are anchored to the natural teeth.
  • Root canal: Root canals help in cases where the cavity has grown deep enough to reach the nerve in the tooth. 

It's important to have any new spots on a tooth checked by a dentist. Cavities should be treated as soon as possible to reduce the risk of pain or other complications. Whether you have a cavity or a stain, seeing a dentist at least once a year can help prevent both.