When it comes to tooth discoloration, the causes can be broken down into two main factors: internal and external. Internal changes occur when something affects the enamel or underlying dentin of the tooth. Some of the most common internal causes of discoloration include frequent antibiotic use, tooth decay, dental restorations, and trauma to the tooth or gums when the tooth is developing.
Unlike internal causes that are often unavoidable, external causes are something you have a little more control over. The most common causes of external discoloration are smoking and certain beverages, such as coffee, tea, and sodas. With a few lifestyle changes, you can minimize discoloration from occurring and, should you choose to whiten your teeth, you must consider these external factors, as they will continue to discolor your teeth.