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.
Whitening (bleaching) is most effectively done in 2 steps. First, the in-office whitening (bleaching) is done which is followed by using bleach trays at home for further whitening or to maintain it. In-office whitening (bleaching), also known as power bleaching, is the quickest way to whiten your teeth.