Plaque is a sticky film that forms on your teeth and is made up of millions of bacteria as well as food deposits.Plaque and tartar are not the same. Brushing only gets rid of one.If not removed properly bacteria up takes calcium and phosphate from saliva and forms a fossilised hard deposit on your teeth called tartar—not the sauce type! 

Tartar is also known as calculus or scale. 

Plaque deposits can be removed from teeth through brushing and flossing but hard and calcified tartar build-up can only be removed by your dentist or hygienist using special instruments.