It’s the chemical taste that filled her mouth that Julee Kessinger remembers most about using Crest Whitestrips. She can also remember the challenge of trying to keep the saliva from inching toward her teeth and peeling off the $40 product that was clinging gingerly to her smile.

Eventually, Kessinger, Overland Park senior, found that the only way to subdue the spit was to hold her mouth open for the entire 30-minute period that Crest advises the Whitestrips be worn. The uncomfortable process proved to be too high maintenance for her tastes, she says.

So when Kessinger won a professional teeth-bleaching treatment at a church auction last November, she was ready to try a new approach to brighten her smile. Today, seeing the results of the professional treatment, Kessinger says she wishes she would have spent the $300 the treatment costs to get the results sooner.

And she’s not alone. Between 1996 and 2000, the teeth-whitening industry grew 300 percent, according to the American Academy of Cosmetic Dentistry. And in 2000, Americans spent $1.3 billion on professional teeth-whitening procedures.

But without a degree in dentistry, the countless teeth-whitening options lining the shelves of the grocery store’s oral hygiene aisle and piling up at your dentist’s office can be confusing and overwhelming. So follow along as we break down the mechanics, the methods and the myths behind getting that Hollywood smile.

Your teeth suffer from two kinds of staining, says Kylie Siruta, a student in the division of dental hygiene at the UMKC School of Dentistry. Intrinsic stains are those found on your tooth’s dentin layer, the area between the outer enamel and the inner blood and nerve center of a tooth. The dentin is naturally yellow, says Siruta, so it’s there you find the cause of the yellow, orange or light brown shading that pops up in your smile. Only peroxide-based chemicals are successful in removing these deeper stains.

Lighter, extrinsic stains can appear on the enamel as a result of everyday contact with dark beverages or from smoking. Whitening toothpastes that include an abrasive ingredient can physically scrape these surface stains from the enamel, Siruta says. But keep in mind that these toothpastes do not contain peroxide ingredients and are incapable of bleaching or lightening the shade of your teeth.

Only two bleaching agents are capable of penetrating the tooth and whitening the naturally yellow dentin layer: carbamide peroxide and hydrogen peroxide. When they come into contact with the tooth, these agents break down and the resulting oxidizing process works to dissolve the extrinsic and intrinsic stains, making the teeth appear whiter and brighter, Siruta says.

The difference between the two bleaching agents — the amount of time the chemicals stay active — is one factor that separates professional treatments prescribed to you by your dentist and at-home whitening treatments such as Crest Whitestrips.

The most commonly used active ingredient in professional bleaching treatments is carbamide peroxide because it maintains its concentration longer, Siruta says. Because of the more inert chemical reaction occurring with the use of carbamide peroxide, it will be active for 6 to 8 hours if left on the teeth, says David Cohen, an assistant professor of dentistry at UMKC. The varying percentages of hydrogen peroxide found in the six types of Crest Whitestrips will only stay active for about 30 minutes, Cohen says.

Another factor that influences the results of any whitening treatment, and one that separates at-home and professional treatments, is the dilution of the bleaching agent when it comes into contact with saliva, Siruta says.

One professional treatment option that minimizes the chance of dilution is the whitening tray. An in-office mold is taken of your teeth, so that when you take the tray home and inject the carbamide peroxide it’s form fitted to your teeth, keeping out any excess saliva that could rinse the bleaching agent off the teeth. At the offices of Galen Van Blaricum, 3310 Mesa Way, whitening trays cost from $250–350, depending on what percentage of the bleaching agent you and the dentist decide is best for you.

The universal-fit Crest Whitestrips and brush-on whitening gels do not provide the same protection from dilution or the same custom fit that guarantees strong chemical-to-tooth contact. And even though the most expensive option for Crest Whitestrips is only $44.98, Kelly Clark, Overland Park junior, decided to pay for professional whitening trays after hearing her friends complain that their Whitestrips did not sit on every tooth the same, causing bleaching inconsistencies.

It was the time commitment that prevented Brad Bailey, Overland Park graduate student, from continuing to use Crest Whitestrips after only one week of treatment. “It got to the point that the last thing on my mind was putting them on for an hour,” Bailey says. To cater to individuals like Bailey who want to complete the whitening process in one sitting, or for those who need to see immediate results, there are in-office professional treatments that contain even stronger percentages of the bleaching treatments. At Cohen’s private practice, this treatment of 38 percent carbamide peroxide costs $550 but takes only 45 minutes.

The bottom line is that the results of whitening treatments depend on the strength of the chemical and the amount of time the bleaching agent is allowed to spend on the teeth. Stronger ingredients that stay active longer and custom-made and supervised treatments cost more but can provide faster results. All you have to decide now is how much your smile is worth.