In a way, teeth are like little nesting dolls. At the center is the pulp, which contains nerves and blood vessels. Dentin surrounds the pulp, and enamel forms the protective outer covering of the tooth's crown.
"Tooth enamel is the highly mineralized outer layer of the tooth," says Ronald Perry, professor in the Department of Comprehensive Care at Tufts University School of Dental Medicine. Enamel keeps the tooth's inner layers safe from the sugars and acids we eat, and from the impact of daily chewing, crunching, and grinding. "It's the hardest tissue in the human body," Perry says.
As hard as it is, tooth enamel wears down over time - and once it's gone, it can't be replaced. Being mindful of certain foods and keeping up good habits can help. So can various products, Perry says, as long as they're used properly.
Over time, enamel can be damaged in several ways. Erosion occurs when acids from foods, beverages, or the stomach dissolves tooth structure. Attrition is wear caused by tooth-to-tooth contact, such as grinding, while abrasion is wear from external friction, such as overly aggressive brushing. These processes can occur together and affect both baby and permanent teeth. Acidic foods and beverages, including juice, soda, and some flavored sparkling waters, can contribute to erosion.
Tooth decay is a separate process: bacteria in the mouth use sugars and starches from foods and drinks to produce acids that dissolve minerals from enamel, eventually creating a cavity. Without treatment, decay can extend through the enamel into the underlying dentin and eventually reach the pulp, which contains nerves and blood vessels. This can cause pain and infection and may require root canal treatment.
A lot of people sit at their desk, typing away, sipping their soda. And the saliva is trying to neutralize the acidity in your mouth, but when they're sipping, the saliva can't catch up and enamel wears away."
Ronald Perry, Professor, Department of Comprehensive Care, Tufts University School of Dental Medicine
Saliva helps protect teeth by neutralizing acids and supplying minerals that help strengthen weakened enamel. People with dry mouth have less of this natural protection and are at greater risk of both erosion and tooth decay. "There's this constant tug of war that happens in your mouth with the acid that pulls the minerals out, while saliva and fluoride are trying to put those minerals back into your enamel," Perry explains
Acid exposure can also come from within. Stomach acid can reach the mouth through reflux or repeated vomiting and erode enamel. Early erosion may go unnoticed, but as enamel thins, teeth may become more yellow and sensitive. "Or people get cracks in their teeth, more cavities, and then it's the domino effect - a tooth breaks down, or a filling breaks down, and then they end up with more costly dental procedures," he adds.
So, how can we best care for our tooth enamel? "We should be taking action every single day, no matter what, no matter what age we are," Perry says. The most important acts are simple. People who grind their teeth should wear a mouthguard, and everyone should brush twice a day for two minutes with fluoride toothpaste and a soft toothbrush, and clean between teeth once a day with floss or another interdental cleaner.
As for toothpaste, "It doesn't matter what brand that you have, as long as it has fluoride in it, and, ideally, carries the American Dental Association's Seal of Acceptance," Perry explains, whether you use a regular over-the-counter fluoride toothpaste, a specialized commercial toothpaste, or a prescription toothpaste with highly concentrated fluoride. As you brush, "just spit out the excess toothpaste without rinsing your mouth out with water, because that'll wash it away," he explains.
Use fluoride mouthwash at a different time from brushing so it does not wash away the concentrated fluoride left by the toothpaste. Follow the product's directions, spit it out, and avoid eating or drinking for 30 minutes afterward. He adds that prescription toothpaste should be used according to that product - and your dentist's - specific instructions.
The same is true of fluoride-rich mouthwashes. "Follow the product's directions, then spit it out," Perry says. "Don't rinse or eat or drink; at night, make it the last thing you do."
Enamel-related products can be misleading. They're sometimes marketed as tools to "rebuild" or "repair" lost or damaged tissue, Perry says. "They deliver fluoride to the tooth. They can't rebuild enamel. Once enamel is gone, it's gone. We can just strengthen it. We can harden it. We can make it more resistant to acid and things of that nature, and protect it from getting cavities," Perry explains. "But we cannot recreate the enamel, because mature enamel contains no living cells capable of regenerating it."
He adds: "Fluoride can help replace minerals lost from weakened enamel and reverse early decay before a cavity forms. It cannot regrow enamel that has physically worn away or replace missing tooth structure."
If you've already lost enamel, and your teeth are yellowing or becoming more sensitive, "have your dentist identify the cause before choosing a whitening product," Perry says. "Whitening toothpastes primarily remove surface stains; they cannot restore lost enamel thickness." If you have enamel erosion or sensitivity, ask your dentist to recommend a fluoride toothpaste with low abrasivity, and avoid aggressive brushing.
Whatever products you choose, Perry encourages everyone to visit the dentist twice a year or "at an interval based on your oral health and risk factors." And if you notice anything different about your teeth, such as suddenly having more cavities, or increased sensitivity to heat or cold, pain, chips, or other changes, make sure to see a dentist. Dentists provide customized care, he adds, and can assess both your tooth enamel and your overall oral health.
As you manage your home care, Perry reiterates: "Be skeptical of any product claiming that it can regrow missing enamel. A toothpaste may support remineralization of an early lesion, but it cannot replace tooth structure. Once enamel's gone, it's lost."
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