Teeth whitening kits typically contain mouth trays that may or may not be customizable, and teeth whitening gel. Since they all follow this basic pattern, you might think they’re all alike, but there can be some big differences that can make a difference in how much they cost and how well they work.
You can buy teeth whitening kits over-the-counter, or you can get them from a dentist. Unsurprisingly, the kits from the dentist can cost 4 to 5 times more than the over-the-counter kits. But they work 4 to 5 times faster and usually give a much better, more even result. Some teeth whitening kits that you can buy in a store aren’t set up the same way as dentist-supplied kits. These might not have mouth trays at all, but instead have a gel that you brush onto the teeth or strips that stick onto the teeth that are coated in a whitening compound.
The teeth whitening gel the dentist uses when you have professional teeth bleaching can contain up to 40% hydrogen peroxide. The peroxide is the agent that actually whitens the teeth. But home teeth whitening kits usually contain carbamide peroxide instead. This is a milder peroxide that takes longer to work. Most OTC kits require that you keep the gel-filled trays on your teeth for up to 4 hours. With some kits, you wear the trays overnight.
Carbamide peroxide isn’t as harsh as hydrogen peroxide, which should never be left on the teeth more than 30 minutes, or whatever time is given in the instructions of the kit. Hydrogen peroxide has more potential to burn and irritate the gums. When you get the treatment at a dentist office, the gums are covered, usually with a brushed on protectant to shield against the gel. Doing this at home would be a challenge at best, so the slower-acting, milder peroxide is used.
Teeth whitening kits sent home by the dentist are more likely to have customizable teeth trays. They may be malleable or “boil and bite,” so that you can make impressions of your teeth to be sure the gel covers every surface. Or your dentist may have taken impressions to make you custom mouth trays. Over-the-counter kits usually come with one-size-fits-all trays, which can end up only whitening the front teeth and may leave gaps where the gel can slide away from the teeth surfaces. The kits that contain brush on gel and strips will lighten your teeth a little, but not nearly to the degree a kit would. These are also the least expensive, usually costing from $10 to $50.
The best teeth whitening kits are the ones that you can afford that give you the best result possible. If you just want teeth that are a little bit brighter but without a drastic difference, the strips or brush on gel may be for you. If you want more even whitening and a more noticeable difference when you’ve finished all the applications, then in-office treatment or less expensive take home teeth whitening kits are probably the best option for you.