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.
Best Answer: It's $450 at the office I work at. That's for the tray, at home bleaching kit, and a few appointments to check progress. We also have a $250 new patient special. Stay away from the professional teeth whitening procedures and from the whitening at home kits.