Starting in 1945, municipal water departments began adding fluoride to their drinking water, notes the National Institutes of Health. The reduction in cavities was first observed in children, followed by a decrease in adults.

You may have frequently heard from your parents or your dentist that fluoride in drinking water is a good thing, but may not know why. Here is how fluoride helps you maintain good dental health:

Minerals at Work on Your Teeth

The enamel on your teeth is composed of a number of minerals, such as calcium and phosphate, to maintain that hard surface. Throughout the day, a cycle of mineral loss and addition happens to your teeth. Bacteria in your mouth reacts with sugar to create acids which dissolve minerals in the enamel.

Your food and water contain fluoride, calcium and phosphate which get reapplied to your teeth. As long as this process stays balanced, your teeth enamel stays healthy.

But when the loss of minerals exceeds the gain, tiny holes develop in the enamel which can become cavities. This can happen when your diet or a disease prevent an adequate supply of minerals from being redeposited on your teeth. The addition of fluoride to the water makes sure you have access to this mineral to strengthen your teeth.

Sources of Fluoride

Tea, wine, seafood and potatoes are a natural source of fluoride. Fluoridated toothpaste and mouthwashes provide fluoride. If needed, prescription-strength fluoride mouthwashes can be prescribed by your dentist. Your dentist can also apply fluoride directly to your teeth in a gel or foam. It can even be painted on your teeth by your dentist.

When You Might Need an Extra Dose of Fluoride

Certain situation may require an extra boost of fluoride to prevent dental problems such as:

• any condition that causes a lack of saliva including medications, illness, and head or neck radiation treatments
• any sign of gum disease which exposes the base of the tooth to bacteria
• a tendency toward frequent cavities
• crowns and bridges which create weak areas in the enamel where they meet your natural tooth enamel

Lifestyle habits can also reduce the amount of fluoride you take in. If you drink mainly bottled water, you may not be getting the dental benefits of the fluoride in the city drinking water. If you have a water filtration system installed in your home, you may be removing fluoride from the city water. Charcoal and ultraviolet filters usually don't filter out the fluoride, but reverse osmosis units can filter out much of it.

You may still get enough fluoride if you use a toothpaste and mouthwash containing fluoride. Your dentist can tell you if additional fluoride treatments would help your teeth.