A periodontal probe is an instrument used by the dentist to see the health of the gums. It has a metal handle and a pointy tip. There are different types of probes. The CPITN probe ends with a small ball . The probe is used to see the depth of gingival sulcus. It has markings on its surface to show various levels of the gums. There is usually a black band that makes it easier for the common distinction between health and disease. Then the severity can be seen according to how much is left of this black band or if it completely disappears. This is an area where the gum contacts the tooth ad it is here that plaque accumulates . In health these pockets are never more then 3mm but in disease states the pockets can become deeper. The CPITN probe measures these pockets and is used to indicate what sort of treatment is needed.