Plaque is a sticky deposit of bacterial matrix that is constantly forming on the tooth. It is an acidic combination of saliva, food, drink, sugar, and bacterial by-product that can cause issues such as gingivitis, tooth decay, bad breath, and periodontal disease. Plaque must be constantly removed by brushing and flossing at least twice daily. Plaque that is not removed can harden and stick to the tooth. At this point, it is called tartar which is also known as calculus. Once tartar has formed only a dentist or hygienist can remove it with special instruments. Tartar that remains on the tooth keeps the soft tissue constantly irritated and even infected.