Ronald Perry, a clinical professor at Tufts School of Dental Medicine, separates the sell from the science
The word “restoring” is more a marketing ploy than an accurate description of what these products really do. We have all heard that once tooth enamel is gone, it can’t be brought back—this is true. But it can be strengthened by repairing weak spots.
These so-called restoring products aid in a process called remineralization. This basically introduces calcium and minerals that adhere to the enamel so it can patch weak spots. This patch is not enamel, but is just as hard and lasting. The more correct description of what happens, which is used by some manufacturers, is strengthening or rebuilding of weak spots.
The most common mineral in enamel is calcium phosphate, which is also called hydroxyapatite. Products that contain this are beneficial, as are those with the mineral fluoride, especially stannous fluoride.
The loss and replacement of minerals in teeth is a natural cycle that happens daily. Calcium naturally found in saliva can be enough to make small repairs. But enamel is attacked when you eat sugars, drink tea, soda or caffeine or consume acidic foods. These things throw the natural healing process out of balance, resulting in weak spots that can become cavities. In other cases, if there is a calcium deficiency elsewhere in the body—in the spine of an osteoporosis sufferer, for example—calcium can leach from teeth to fill this need. Tooth grinding can also damage enamel over time, as can gastrointestinal problems and certain medications, such as aspirin and antihistamines.
People need to be alert to tooth sensitivity or discoloration, both warning signs of demineralization. If too much enamel has been lost, they might need tooth bonding or crowns. Dentists can also prescribe stronger strengthening toothpastes and mouthwashes than those found at a retail drugstore.
Because they strengthen enamel, restoring toothpastes or mouthwashes can help prevent decay. But this is only effective in combination with good oral care habits, such as avoiding excessive sugars, starches or acidic foods, seeing a dentist regularly and being alert to medications or medical conditions that may affect your teeth.