What does plaque look like?

Plaque is a soft, colourless substance which is difficult to see until the coating is quite thick. It collects on the surfaces of teeth, mainly next to the gums and between the teeth.

Is tartar the same thing as plaque?
Not exactly. Tartar (calculus) is formed when substances in the saliva, such as calcium, combine with plaque making it hard. This happens commonly behind the lower front teeth. Once calculus has formed, it will have to be removed by a dentist or dental hygienist.