Tooth whitener Buying Guide

Getting started

Professional tooth whitening in a dentist's office can brighten your smile in as little as one visit, but it can cost hundreds of dollars. Over-the-counter home whitening kits cost far less, and there's an ever-expanding array of options--including strips that dissolve, strips that stick on, and even light-activated trays.

Each one of the 82 staff members in our test panel was given a product and asked to use it as directed for the number of days recommended by the manufacturer (from five days to three weeks). We used a digital color-measuring device to assess staff members' tooth color before and after the course of whitening. The testers also described their experiences with the product. The Ratings are based mainly on whitening scores.

Here are our findings:

The best were strips

The one exception was Target's Whitening Dissolving Strips, near the bottom of the Ratings. The i-White, a tray with a battery-operated light designed to speed whitening, claims to provide "dental professional results at home," but it whitened teeth the least of all the products.

Sensitivity was common

All the packages say that users might experience temporary tooth and gum sensitivity, and some of our testers complained of irritation or other discomfort while wearing the products. Using a sensitivity-reducing toothpaste might help to lessen discomfort.

Trays didn't always fit

They come in one size and are unlikely to fit all mouths equally. An ill-fitting tray can cause discomfort, and it might prevent teeth from getting proper contact with the whitening agents. "I felt like I had to clench my upper lip against the tray to keep it from moving," a tester said. Other common problems reported: Difficulty speaking with the tray in place and excess gel oozing out and down the throat.

Bottom line

At-home kits can brighten teeth somewhat, and for much less than what you'd pay at a dentist's office. But don't expect extreme results. And it's hard to say how long the whitening effects last. Other tips:

Don't use whiteners if front teeth have caps, crowns, veneers, dentures, or white fillings. Whiteners work only on natural teeth.
To reduce stains, go easy on tea, coffee, and red wine; don't smoke; and brush teeth after meals. Soft drinks--colas as well as clear sodas--can also contribute to staining by eroding tooth enamel.
Note that yellowed teeth are more likely to whiten than teeth with a gray, brown, or bluish cast.