1 concentration gradient The difference in the concentration of a chemical across a membrane. 2  cytoplasm The living substance inside a cell (not including the nucleus). 3  diffusion The movement of particles (molecules or ions) from an area of higher concentration to an area of lower concentration.
Not all stains can be lightened by over-the-counter or professional bleaching, and your dentist will be able to give you guidance. If you have sensitive teeth, gum disease or teeth with worn enamel, your dentist may discourage tooth whitening.
Discover the power of the 5 minute bleach whitening gel. It contains the same active ingredient used professionally by dentists (the bleaching action of peroxide) to whiten and brighten teeth, gently lift away stains and reduce yellowing in a strength developed for at-home use.