Plaque is a clear, sticky substance made in the mouth. It clings to the teeth and gums. Plaque has bacteria that make acids and other chemicals that can damage the teeth, gums, and bone if the plaque is not removed.
Plaque forms all the time, but it can be controlled by proper brushing and flossing.
If plaque is not removed, it hardens into a rough substance called tartar or calculus. This is hard to get off the teeth. It is often removed as part of a dental cleaning and exam.
WebMD Medical Reference from Healthwise