There are two types of teeth whitening: intrinsic and extrinsic. The former requires whitening the inner part of the tooth (dentin) using a whitening gel or bleach. This type of teeth whitening procedure is ideal for people whose teeth cannot be easily repaired by any whitening toothpaste or treatment. The latter, on the other hand, is a procedure that requires the removal of stains on the enamel due to smoking and drinking dark-colored beverages. Extrinsic whitening is usually done using a polish during teeth cleaning.