Live bacteria that are associated with periodontal disease can be identified using an oral phase contrast microscope. A sample of plaque from under the gum can display the types of active organisms present before bone loss around the tooth occurs. The normal bacteria seen in the pockets are cocci. As the disease process advances, rods and vibrio develop. In the more advanced stages, spirochetes are identified. The most advanced cases have amoebas, clustered spirochetes, and trichomonads. When a patient looks at the microscopic sample on the TV monitor and sees active bacteria, they understand how their treatment is progressing.