Let’s look at home whitening kits and why you should avoid them. It shouldn’t come as a surprise that we, as a society, value a good-looking smile. In a recent survey by the American Academy of Cosmetic Dentistry, 99.7 percent agreed that a smile is an important social asset. The flipside of that is that an unattractive smile can be seen as a handicap. And in fact, 74 percent of those surveyed felt an unattractive smile could hurt a person’s chances for career success.

And one of the most common qualities they cited among those with unattractive smiles? “Discolored, yellow, or stained teeth.”

Again, not exactly breaking news. If you’ve spent any time in a CVS, Walmart, or the like over the last few years, you already know how important white teeth are. In that span, home whitening kits have gone from existing on the periphery to taking over entire aisles. Americans are spending more than a billion dollars a year on teeth whitening products.

But, while most home whitening kits are comprised of the same components (strips or trays, bleach), not all teeth staining is the same. If you’ve ever looked closely at your teeth in a mirror, you may have noticed that the discoloration varies subtly. Which could be one reason why, if you’ve ever tried whitening your teeth at home, it had little, if any, effect.

There’s an even greater concern at hand, though: Those kits may actually be destroying your teeth.

What causes the discoloration in the first place?

There are basically two ways your teeth can become discolored: from the outside in and the inside out. The former is the more common and the easier to correct. Coffee, wine, and countless other foods and drinks we consume on a regular basis (chocolate!) leave behind particles that lodge in the teeth’s protective enamel and gradually stain our teeth.

When the staining originates inside the tooth, it’s because the dentin, the bony tissue beneath the enamel, becomes damaged. It can occur as the result of injury, the use of some medications, and bad oral hygiene.

Hard as the enamel is, it’s also thin. Dentin actually makes up most of the tooth’s structure. And it’s already darker than enamel. So, if your enamel wears down—which occurs naturally as we age, though not brushing and flossing enough or consuming too much soda and juice can speed up the process—the dentin can begin to show through.

A blow to the tooth could damage the nerves and tissues at its core, cutting off the blood supply. The nerves and tissues can also become infected as a result of an untreated cavity, which could interfere with the blood supply. In both cases, the tooth could turn gray as the damage worsens.

Tetracycline, a type of antibiotic, can also cause teeth to gray if it’s used during childhood, when teeth are still developing. It can also affect developing babies’ teeth if it’s taken during pregnancy. But that effect is much more widely known today, so doctors generally won’t prescribe it in those cases. There are, however, certain high blood pressure medications and antihistamines that can have the same effect.

In those cases where the discoloration begins within the tooth, not even a professional whitening is going to do much to improve the appearance because there are deeper dental issues at play. The appropriate treatments, while not directly addressing the discoloration, will ultimately improve the tooth’s appearance.

Also worth noting, whitening of any kind is typically not effective on restorations—tooth-colored fillings, dental crowns, porcelain veneers, dental implants. At the very least, using a home whitening kit if you have restorations will result in uneven whitening. (The teeth without restorations will appear lighter than those with them.) But new research is indicating that it may also cause the restorations to break down.

Whitening is also less likely to work if you have other oral health concerns, like tooth decay or periodontal disease. The whitening solutions penetrate any existing decay and the inner areas of the tooth, which can cause a painful sensitivity.

Ineffectiveness is the least of the concerns

For all their popularity, there’s little evidence supporting that home whitening kits do what they say they do. A study published late last year found “low to very low-certainty evidence over short time periods” that home whitening kits were any more effective than a placebo.

But the even-greater cause for concern comes from research that was presented this spring at the annual meeting for the American Society for Biochemistry and Molecular Biology in Orlando. In three new studies, undergrad students working under Kelly Keenan, PhD, an associate professor of chemistry at Stockton University here in New Jersey, found that hydrogen peroxide, the active ingredient in over-the-counter whitening strips can damage dentin, that bony tissue beneath the enamel.

It was already established that hydrogen peroxide can penetrate the enamel and dentin. But Dr. Keenan and her students were able to show that the collagen in the dentin layer—which makes up most of the tooth—decreased after the teeth were treated with whitening strips.

Whitening strips, in other words, are capable of eating away at our teeth.

The safe way to prevent staining

What to do, then? Get in front of it. Even if you’re already experiencing some discoloration, you can prevent it from worsening by following a few basic steps:

  • Brush your teeth at least twice a day for two minutes at a time and floss at least once a day. (Check out our oral hygiene primer to make sure you’re doing both correctly.) Flossing’s the only way to clean between teeth and under the gums, which is where most cavities, stains, infections, and other kinds of dental damage begin.
  • Try to avoid sugar, starches, and highly acidic foods and drinks as much as possible. If you do partake, brush afterward, but not immediately afterward. Wait about an hour because acid can temporarily soften your enamel.
  • And get a professional examination and cleaning twice a year. A hygienist can scrub those hard-to-reach spots. A dentist or periodontist can also treat any issues before they worsen and offer advice tailored to your lifestyle on how to stave off further staining.

If it’s been a while since you’ve seen a dentist, or if you have other dental concerns that need to be treated before addressing your teeth discoloration, contact my office and schedule an appointment. The earlier the intervention, the sooner you can get back to smiling with confidence. and remember to avoid home whitening kits!