The Chairside Instructor 7 Plaque and its Effects Prevention and Diagnosis Before professional dental cleaning After professional dental cleaning Buildup of tartar can also be seen on x-rays. Plaque and Tartar Plaque is a soft, sticky film with bacteria that constantly forms on teeth. It can cause tooth decay and gum disease. Plaque that is not removed can harden and form tartar (also called calculus), which makes it difficult to keep your teeth clean. Only a professional dental cleaning can remove tartar from your teeth. Plaque can harden into tartar if not removed and can build up around your teeth. This makes it harder to keep them clean on your own. Image ©Elsevier Inc. All rights reserved.