Dental plaque is the soft, sticky layer of bacteria on the surface of gums and teeth, particularly along the gum-line.  It can be removed relatively easily by regular brushing. You can actually see dental plaque using disclosing tablets.

Plaque is made up of millions of bacteria. About seventy percent of the dry weight of the plaque is bacteria, the remainder being carbohydrate and other substances of saliva.  Regular brushing is the best way to get rid of plaque and avoid oral health problems.