A bright, white smile is often associated with health, youth, and confidence. So when your teeth start to take on a grayish hue, it can be concerning. Gray teeth are not always a sign of poor oral hygiene — they can result from a variety of internal and external factors. Understanding what causes this discoloration and what your Vienna dentist can do to restore your smile is the first step toward regaining your confidence. Here are four common causes of gray teeth and how dental professionals address them.