Good oral hygiene is a tried-and-true method for keeping your smile looking its best. Toothpastes gently buff out stains from the surface of your teeth. Whitening toothpastes work the same way with more ingredients; they don't bleach your teeth. Flossing gets rid of food and bacteria that could harden into plaque, which makes your teeth look dull and darker.
This technique is popular in Ayurvedic medicine. You swish a tablespoon of oil (such as sesame, coconut, or olive oil) around in your mouth for up to 20 minutes to "pull out" bacteria. A recent study found that using coconut oil could prevent tooth decay, but there's no science to support it leaving a sparkle.
Besides helping batter rise, it's also a mild abrasive that scrubs away stains. You could try using a DIY paste of baking soda, but you'll probably get better results by switching to a toothpaste with sodium bicarbonate. Studies show brushing with products that have baking soda will work on surface stains over time.
Malic acid in apples boosts saliva to wash away acids. Toothpastes with bromeliad, a compound in pineapple, help whiten teeth. But there's no evidence that eating these fruits will make your grin gleam. Skip the strawberries, too. A study in Operative Dentistry found that brushing with a mixture of them and baking soda had no whitening effects. Even worse, the citric acid in strawberries can break down enamel, the outer shell of your tooth.
It's the bleaching agent found in most home whitening kits. It actually changes a tooth's colour. One study found that painting an over-the-counter gel with 6% hydrogen peroxide on teeth made a noticeable difference after 2 weeks. The inexpensive bottles of liquid you can buy in a drugstore usually have a lower percentage. And the American Dental Association says swishing will probably irritate your gums before it whitens your teeth.
Gargle before you brush to help kill bacteria and remove stains, they say. You'll get a whiter smile, they say. Sorry, no studies confirm these claims. While it can brighten the taste of your salad dressing, don't expect apple cider vinegar to brighten your teeth.