Technically called a prophylaxis, it removes the stains and hard deposits (calculus) from the teeth that your toothbrush can’t get off. It is usually performed at an interval of 3 to 6 months, depending on the rate at which stain and calculus accumulate. The process begins as a result of the growth of bacteria, which are normal inhabitants of everyone’s mouth. They grow around the teeth and below the gum line to form a soft, sticky mass called plaque. Removal of the plaque is the goal of daily oral hygiene – brushing and flossing. Minerals from saliva will gradually be absorbed into the plaque and cause it to harden into calculus. At this point, a toothbrush and floss just won’t get the job done. As calculus accumulates, larger plaque deposits can form in areas in areas where the toothbrush can no longer reach. The problem can snowball into a real ‘coral reef’.