Please choose the correct ending to complete the given sentence: Health: [header] How to whiten your teeth when you have braces [title] Consider using whitening toothpastes. [step] Look for brands that are american dental association (ada) approved, because they contain fluoride: a mineral essential for dental health. [substeps] Whitening toothpastes contain special abrasives such as baking soda and peroxide to remove surface stains from teeth.

Ending1: Read product reviews to find out if there are any approved brands in your area you can use. [title] Find some local dentists or dental agencies. Ending2: Expect at least a teaspoon of fluoride a day-it takes some time to get the whitening effect. [title] Try combining products with specific dental ingredients. Ending3: However, these products will only remove surface stains. They will not change the color of your enamel entirely. Ending4: Always follow the manufacturer's instructions on brushing and flossing. [title] Brush and floss your teeth once daily.

Answer format: ending1/ending2/ending3/ending4