Plaque is very personal. It forms from countless combinations of foods, individual acid and moisture levels in a person's mouth, and internal and exterior bacteria from any number of sources. Back molars, the ridges along dental work, and the lower faces of teeth near the gum line are places where plaque accumulates the most, and these areas often are harder to get to with a quick brushing. Tooth decay and bad breath are some obvious signs that plaque bacteria is thriving in a mouth, but these problems develop long after plaque has started to form.
You can't see plaque with the naked eye until decay from plaque forms, but you can feel the sticky film, note some dull sliminess and just know it's there if you've missed some appointments with the toothbrush. You can use disclosing tablets, which typically look like little red pills, if you want to see where plaque is forming. Chewing a disclosing tablet releases a safe dye that mixes with saliva and attaches itself to areas covered with plaque bacteria. Some dental professionals use the tablets to teach young children where they need to steer their toothbrushes, and adults can use the dye after brushing to see what areas they may be missing.
Removing plaque is important for oral health. Bacteria and acids wear down tooth enamel, the protective covering of teeth, and over time, cavities, also called dental caries, form. In addition to causing cavities, plaque can lead to gum problems. As it's forming, plaque is soft, but if not removed after eating it can harden around the base of and in between teeth, making it harder to clean thoroughly at the gum line.
Hardened plaque is called tartar or calculus, and it can irritate gums and cause bleeding and swollen gum tissue, both signs of gingivitis. Gums can recede, pulling away from the surface of teeth and creating pockets for further plaque debris as well. More than half of all people in the United States have gingivitis, which can lead to gum, or periodontal, disease, but gingivitis is very treatable in its early stages. Gum disease is preventable once gingivitis is found, but it is not reversible -- only treatable.
Poor gum health from plaque build-up also is linked with physical conditions outside of the mouth, including heart disease, low infant birth weights and blood sugar issues, for example. Although gum disease hasn't been definitively identified as a cause of such health problems, it is commonly found in connection with these conditions [source: NIH]. In the case of heart disease, the plaque that causes hardened arteries and blocks blood flow is not the same plaque film found on the teeth, but some strands of bacteria that lead to gum disease and cavities also have been shown to get into the bloodstream, leading to clogged arteries. A direct link, however, hasn't been identified [sources: Harvard University; Ray].
Getting at the plaque while it's still soft rather than being soft on plaque can prevent many of these issues. We'll brush up on how, next.