One of the wonders of the mouth is how the gums wrap tightly around the teeth much like a turtleneck collar hugs the neck. At the edge of the gumline, the gum tissue folds back underneath itself, creating a snug, 1- to 3-millimeter furrow around each tooth (the “gingival sulcus”). To measure the health of the gums, the hygienist or dentist gauges the depth of the gingival sulcus at several points around each tooth by inserting a thin measuring rod (periodontal probe). A depth of over 3 millimeters may indicate that a pocket is forming between the tooth and gum, which is evidence of gum disease. Treatment prevents mild gum disease (gingivitis) from progressing to severe gum disease (periodontitis).
P.S. Plaque that is allowed to build up in the gingival pocket may lead to possible infection and damage that reaches even further down the tooth, eventually compromising the tissues that hold it in place.