Americans are becoming increasingly concerned about the whiteness of their teeth.

Sifting through all the potential treatments can be daunting, though, especially when many people do not know the truth about the methods.

Many teeth stains are caused by the usual suspects: age, tobacco, and coffee or tea.

Genetics also plays a large role in the color of one’s teeth, and as a result, some people have teeth that simply will not bleach.

Other types of stains can be caused by antibiotics, such as tetracycline or too much exposure to fluoride.

“We have some good indicators, but we’re still largely guessing,” said dentist to the stars Gregg Lituchy. .

“The more yellow and more opaque teeth tend to bleach well, whereas someone who has blue-gray teeth, which are more translucent, will likely be disappointed. Even we can be surprised. It’s not a surefire thing.”

Two of the most popular methods for removing stains from teeth are whitening, which Lituchy said affected the outside of the tooth, and bleaching, which he said penetrated deeper to the core.

There is an enormous market for brighter teeth.

In 2004, Americans spent nearly $2 billion on whitening and bleaching their teeth.

In dentists’ offices, bleaching is the most requested procedure among patients between 40 and 60, according to a 2003 American Dental Association survey.

In 2004, one in five patients asked their dentist about whitening, while just one in 10 did in 2001.

Whitening toothpaste is the most popular kind of toothpaste on the market.

Consumer Reports tested 41 brands of toothpaste to see whether they really whitened teeth — as many of the makers claim — and found no correlation between those claims and stain-removing ability.

“Teeth get bleached based on how long the gel stays in contact with the structure. When you brush your teeth, the gel is rinsed out and gone in under two minutes,” Lituchy said. “You need the peroxide to stay on the tooth long enough for it to work. White strips stay on 30 minutes twice a day — long enough. †However, you also need to understand that the percentage of hydrogen peroxide is much lower than what you can get from power bleaching in the dentist’s office or from the at-home tray bleaching.”