The two companies, which take in 84 percent of the money Americans spend on tooth whiteners, and which last year spent an estimated $81 million marketing them, are now trying to rope in new customers with offshoot products for nighttime use.

Enter SexySmile, the portable, powerful tooth whitener featuring a lip gloss at the other end.

Then I found the tooth whitener for sale on the minibar, and remembered where I was.

It has a versatile host, Mike Levey, who might gasp while interviewing the inventor of a new tooth whitener on one show and in the next seem awed at how easy it is for a klutz like him to iron appliques on T-shirts.

In medieval times, mastic was highly valued by sultans' harems as a breath freshener and a tooth whitener.

The American Dental Association has recently issued a cautionary note on tooth whiteners, as it usually does when new or modified kinds of treatment come out.

A survey last year by Dental Products Report, a trade journal, found that 96 percent of American dentists offer at-home tooth whiteners, and 55 percent provide bleaching in their offices.

Just about everyone wants a brighter smile, but for some people, tooth whiteners and toothpastes with peroxide-based bleaching solutions can cause sensitive teeth.

KEVIN ROSS, a psychologist in Queens, is a serial tooth whitener.

Turn back time with the latest lip enhancers, tooth whiteners, and more.