Will whiteners give you a movie star smile?

Who wouldn’t want a smile as bright as Julia Roberts’? Well, thanks to modern cosmetic dentistry, we can all aspire to flashing a beautiful set of pearly whites. Teeth whitening products flood our supermarket shelves and doctors promote their power bleaching processes any time you’re in one of their chairs. From whitening mouthwashes, to toothpaste, to chewing gum, to polishes, to bleaching trays, to instant whitening treatments, we are bombarded with teeth brightening products. Last year, Americans spent more than $1.4 billion on over-the-counter whiteners, according to the American Academy of Cosmetic Dentistry.

That’s a lot of cash to get some flash, so we decided to try some of these treatments to see how well they work. Under the attention of Dr. Marc Lowenberg, a New York City cosmetic dentist known in some circles as “the dentist to the stars,” we asked three women to try three different products. Before we got started, Dr. Lowenberg reminded us that it’s hard to predict who will see results with a particular product and who won’t, no matter what she uses. “Everybody can attempt to bleach their teeth, but the kinds of results you get vary from person to person,” he said. “There is no way of definitely predicting what color your teeth are going to end up.”

We started with Crest White Strips. The kit, which you can buy in your local drug store for about $34, promises to get your teeth up to six shades whiter in just seven days. We gave it to Fabiola Antezana, 34, of New York City, and asked her to follow the directions. We took photos of her teeth, and then checked back with her a month later. She told us she had some gum sensitivity and had to stop using them for a day or two, but went back to finishing out the treatment. In the end, Antezana saw little difference between her “before” shots and her “after” ones. Dr. Lowenberg was surprised. He said most people have some success with the strips. A company spokesperson told us: “While individual results will vary when using whitening products, millions of consumers have already tried Crest White Strips and received visibly whiter smiles.”

Next we tried out Go Smile on Muffy Lewis of New Canaan, Conn., who recently turned 50 and thought it was time to brighten up her look. Go Smile, which costs about $90, requires you to “paint” its whitening solution on your teeth. After one month, Lewis was disappointed: “My teeth aren’t any brighter as they promised.” Dr. Lowenberg believed the product wasn’t as effective as other treatments, because the solution can easily wash off your teeth. With a whitening tray or Crest White Strips, the solution stays pressed up against your teeth. The makers of Go Smile told us it is unfair to judge a product by just one participant, claiming that many clinical studies support the success of their product.

Finally, we tried out the big-bucks, power bleaching treatment used in the dentist’s office. Promising instant success, this can cost anywhere from $300 to $600. In addition, most dentists want you to buy the trays, which cost about the same amount. Stephanie Fray of New York City decided to give this a try, so Dr. Lowenberg bleached her teeth in his office.

Four weeks later, we asked Fray if her teeth were any whiter. “I don’t necessarily notice a difference every day,” she said. But she added, “Other people tend to notice my teeth are a bit brighter.” Dr. Lowenberg was also pleased with her results.

As with any whitening product there is always “fade back.” That’s the darkening that occurs from drinking red wine or coffee or smoking cigarettes. All these treatments require maintenance. Again these were just three women using three different products. This was not a scientific study.

Janice Lieberman is the “Today” show’s consumer correspondent. She joined NBC News as a consumer reporter in 1999. She is author of “Tricks of the Trade: A Consumer Survival Guide.” She is a graduate of Rutgers University.