In a survey of potential patients, five major concerns were raised repeatedly, some real ... and some unreal.

- Can tooth whitening remove all stains?

Although advances in technology have greatly improved the effectiveness of the procedure, there are some stains that can be lessened but cannot be removed completely. One problem that is notoriously difficult to solve is staining caused by tetracycline, an antibiotic that was belatedly found to discolor developing teeth. If used by a pregnant woman, it can even affect the unborn child's teeth.

Other stains, such as those caused by red wine, coffee, tea, or smoking, are easier to remove. However, if you contimue to use those products then your newly-whitened teeth will begin to discolor again. Repeat treatments can help to maintain the colr of of your teeth, but diet and lifestyle changes will be an advantage.

- Will I be hassled by paparazzi?

Regardless of how beautiful, bright, and attractive your smile becomes, it is unlikely that you will be the focus of pushy photographers for celebrity tabloids. You should still be be able to visit your local mall, go out for dinner, and even sit on the beach without attracting unwelcome attention. Unless you're Brittany Spears.

- Will the treatment be uncomfortable?

Possibly, yes; patients report two distinct types of discomfort. If the bleaching compound is in contact with your gums, tongue, or other soft tissue for a length of time those areas may become irritated. Also, some people find that their teeth become sensitive to hot and cold temperatures. All of these side-effects should be mild, and shouldn't last more than a day or two.

- If I live near the coast, is there a danger to passing ships?

Your dentist will be able to give you a shining and alluring smile. But even with the brightest smile you are very unlikely to be mistaken for a lighthouse. Your concerns about sailors in peril on the sea are generous, but you need not worry.

- Is tooth whitening very expensive?

Every course of treatment is different, and costs may be higher in some areas of the country than others. But it's reasonable to assume that an extensive procedure in your dentist's office will cost between $800 and $1,500, depending on your particular circumstances. While tooth whitening isn't covered by most insurance plans, some clinics will offer payment plans or other financial arrangements to make the cost more manageable.