While teeth whitening is considered safe, you may experience some side effects from treatments. Teeth sensitivity and irritated gums are most common with whitening. Avoid getting the treatment gel on your gums as well as not ingesting it. Keep in mind that you cannot whiten your teeth on a permanent basis. You’ll need to seek whitening treatments every so often for both extrinsic and intrinsic discoloration. Also, keep in mind that these products are for natural teeth. You’ll need to talk to your dentist about how to unify the color of your teeth if you have implants, crowns, bridges, or dentures. Make sure to use the method that fits your needs and always follow the directions for the product.