Certain foods and drinks, such as coffee, red wine, cherries, blueberries, and tea, can cause dental staining. These types of stains are known as extrinsic stains because they develop on the exterior of your tooth enamel. Keeping your teeth cleaning appointment with your dentist will get rid of pigment stains on your teeth, but other stains, such as those that cause your teeth to turn gray, may be more difficult to treat. Here are some common causes of gray dental staining, and what you can do about them:

Tetracycline 

The antibiotic tetracycline is used to treat bacterial infections such as those of the urinary tract and skin. In the past, it was commonly prescribed to pregnant mothers and young children, however, it is not commonly prescribed to this demographic anymore. Tetracycline can cause gray staining of the teeth, which may cover the entire tooth, or appear only as grey horizontal lines. The staining intensity can vary from very light to dark and is typically unaffected by professional teeth cleanings or bleaching. If you have gray stains on your teeth as a result of tetracycline, your dentist may recommend veneers, which are porcelain or resin covers that fit over your natural teeth to hide imperfections.

Injuries

Damage to your tooth enamel from an injury can cause your teeth to turn gray. Dental trauma can damage the tooth enamel when blood flow or circulation to the tooth is interrupted as a result of the injury. In addition to gray stains, traumatic injuries to the teeth can also cause brown or yellow discoloration or stains. Like tetracycline-related stains, dental stains caused by dental trauma cannot be treated by whitening treatments. These types of stains are known as intrinsic stains, meaning they are inside your tooth, rather than on the exterior.

In addition to porcelain veneers, bonding can hide gray, brown, or yellow intrinsic staining. Highly pigmented foods can stain the bonding material, so it is important that you avoid coffee, tea, and other highly pigmented foods and drinks for a couple of days after your bonding procedure. It is important to note, that you will still need professional teeth cleaning services if your teeth are bonded. 

If you have gray stains on your teeth because of tetracycline or dental injuries, see your dentist for a cleaning appointment. He or she will examine your teeth and recommend the best treatment option for the type and extent of your dental stains.