Because oranges are naturally acidic, using orange peels as a natural teeth whitener can actually cause damage to the enamel of your teeth, weaken your teeth, and have lasting negative effects on your smile.
Lemon, orange, or banana peels
It’s believed that the compound d-limonene and/or citric acid, which is found in some citrus fruit peels, will help to whiten your teeth.
Gently rub the fruit peels on your teeth for about 2 minutes. Make sure to thoroughly rinse out your mouth and brush your teeth afterward.