How Does Tooth Whitening Work?

There are many ways to whiten your teeth — from whitening toothpastes and other products that can remove many surface stains for very little cost, to light-activated whitening techniques in a dentist's office that cost up to $1,000 and can produce dramatic results.

All whitening techniques work in one of two ways:

1. Bleaching removes both deep & surface stains.

   Bleaching procedures change your natural tooth colour, usually anywhere from five to seven shades brighter. In-office (chairside) whitening and at-home (tray) whitening both rely on bleaching. Bleaches contain an active ingredient, most often carbamide peroxide or hydrogen peroxide in concentrations of 10-22%, which helps remove both deep and surface stains. There are significant cost differences between different bleaching procedures:

   • A light-activated whitening session in a dentist's office, sometimes called chairside bleaching, can cost $500 or more and results in instantly and often dramatically whiter teeth. However, after a year or so of eating and drinking normally (coffee, tea, soft drinks), your teeth become slightly discolored again and develop new stains. With chairside bleaching, you have to pay the $500 to have white teeth again.

   • A custom mouthpiece created by your dentist for in-home bleaching costs around $300, and you typically wear it several hours a day or overnight for two weeks. When you notice new staining, you just wear the mouthpiece again for a night or two to take the stains off.

   • Over-the-counter products for whitening teeth (those found in a drugstore) include boil and bite tray application, whitening gels applied with a brush, and whitening strips in a price range of $10.00 to $45.00.

2. Abrasion removes most external stains.

   Non-bleaching procedures work by physical and/or chemical action to help remove surface stains. All toothpastes rely on mild abrasion to remove surface stains between dental visits. Whitening toothpastes have special chemical or polishing agents that provide additional stain removal. A professional cleaning by a dentist or hygienist also uses abrasion and polishing to remove most external staining caused by food and tobacco.

Everyone responds differently to different whitening procedures. Some people respond well to whitening toothpastes, while people with gray teeth or other serious discoloration may require porcelain veneers or bonding (discussed elsewhere in this section) to achieve the smiles they've always wanted. Only your dentist or hygienist can determine what's right for you.

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