Which Teeth-Whitening Methods Work Best?

— -- With demand for a whiter smile growing, there is a wide field of products that promise to brighten teeth and bring dull or stained choppers back to pearly white. But which ones are worth the money?

Sales of toothpastes with a whitening claim jumped 22 percent last year at supermarkets, drugstores and mass merchants. But the surge in toothpastes has been outstripped by over-the-counter bleaching products. Leading in sales figures is Crest Whitestrips, which came out last May. Procter & Gamble is projecting at least $200 million in first-year retail sales for Whitestrips.

But are there real results for the money spent? In general, people who use the products start to see a real difference when their teeth turn three shades lighter or more, according to Good Housekeeping, which tested five alternative ways to whiten your teeth.

Here are the magazine's findings.

Best Whiteners

Overall best: the Crest Night Effects do-it-yourself product and the in-office bleaching at Britesmile and Zoom! centers. All three lightened teeth up to five shades.

Crest Night Effects, which costs $14.99, was introduced in stores in March. To try it out, six Good Housekeeping testers applied paint-on gel to their teeth right before bed for 14 nights. The product uses "LiquidStrip Technology," which holds the whitening agent to the teeth while you sleep. The whitening gel forms a LiquidStrip coating on the teeth that works to remove stains and loosen stain-causing buildup. In the morning, users brush the LiquidStrip coating and stains away. Night Effects was found to lighten teeth from two to five shades, according to a dental shade gauge for teeth. But testers noted that the gel felt "goopy" after application.

Britesmile and Zoom! The other top alternatives were in-office bleaching at Britesmile and Zoom! centers. The price is $400 to $600, depending on location. A special light activates hydrogen peroxide gel applied to teeth (15 percent of hydrogen peroxide in the Britesmile gel and 25 percent for Zoom!). Both concentrations are lower than some home whitening gels, which have 35 percent to 50 percent. The procedure takes about one hour.

Britesmile and Zoom lightened teeth by three to five shades. One tester experienced sensitivity.

Second-Place Whiteners

In second place were Crest Whitestrips and Colgate Simply White, which lightened teeth up to three shades.

Crest Whitestrips, under $30. Testers applied flexible strips twice a day, 30 minutes at a time, for 14 days and the results were compared with those of other testers, who used five kits with trays that fit around their teeth. The Whitestrips were tops for convenience and comfort and they lightened teeth an average of three shades. They came in second for whitening, though. (Whitestrips have received the Good Housekeeping Good Buy Award.)

Colgate Simply White, $15.99. Testers used this brush-on gel twice a day for 14 days. Teeth were lightened one to three shades. Testers found it hard to keep their mouth open for 30 seconds after applying, though new directions say this is not needed.

Third-Place Whiteners

Teeth-whitening gums, Trident White and Aquafresh, each lightened teeth up to one shade.Twelve testers chewed one of six gums four times a day for six weeks.

Trident White and Aquafresh Whitening Dental Gum were best. Each whitened teeth up to one shade (for two testers). Each of the gums has a different whitening ingredient. Price: $1.50 to $3.29 per pack.