Inadequate fluoride: This mineral is an important enamel ally that can make teeth stronger and can enhance saliva's remineralizing, anti-decay properties. Most people get adequate fluoride exposure through drinking fluoridated water and brushing twice daily with fluoride toothpastes.

But people who drink primarily bottled or filtered water may not be getting adequate fluoride. Even with adequate fluoride, dry mouth can throw off the normal balance teeth need to stay healthy.

A dentist may recommend fluoride treatment to protect and strengthen tooth enamel. Fluoride can be applied two to four times a year. Another option is nonprescription fluoride rinses available in drugstores.

Also helpful is limiting tooth enamel contact with acids that come from many foods and beverages. Examples include citrus fruits, tart candies, diet and regular sodas or sports drinks, fruit juices and wine.

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