More than 50 years ago, examinations of people entering the military showed that Americans' teeth were in pretty bad shape. Few people took good care of their teeth. There were no guidelines for how often you should see a dentist. Many dentists focused on fixing problems rather than preventing them.

Dental and health organizations decided there was a need to set standards for preventive dentistry. They didn't have much evidence, so they made a "best guess" recommendation. They said people should go to the dentist twice a year for checkups and cleaning.

This proved to be a useful rule of thumb and has remained common. Even if you take excellent care of your teeth and gums at home, you still need to see your dentist regularly. Your dentist can check for problems that you may not see or feel. Many dental problems don't become visible or cause pain until they are in more advanced stages. Examples include cavities, gum disease and oral cancer.

Regular visits allow your dentist to find early signs of disease. Problems can be treated at a manageable stage.

On average, seeing a dentist twice a year works well for most people. A few people can get away with fewer visits. Others may need more frequent visits. People with very little risk of cavities or gum disease can do fine seeing their dentist just once a year. People with a high risk of dental disease might need to visit every three or four months, or more. This high-risk group includes:

• Smokers
• Diabetics
• People with current gum disease
• People with a weak immune response to bacterial infection
• People who tend to get cavities or build up plaque

The schedule for any person may change during a lifetime. In times of stress or illness, you may need to see the dentist more often than usual. The dentist may help you to fight off a temporary infection or treat changes in your mouth.

If you take good care of your teeth and gums at home and your dentist doesn't find any cavities or gum disease for a few years, he or she may choose to lengthen the time between visits. Ask your dentist the best schedule for your routine dental visits.