Periodontology - Plaque

Dental plaque is one of the main causes of tooth decay and gum disease. A sticky biofilm that contains bacteria and fungi, plaque is found on all the surfaces of the teeth, both above and below the gumline. To prevent tooth decay and gum disease, plaque must be removed and its production and accumulation must be controlled with proper oral hygiene. If allowed to remain on the teeth, dental plaque can become acidic and cause dental cavities, or it can harden and become dental calculus; dental calculus can only be removed by a dental professional, and, when it is left unattended, it provides a breeding ground for the accumulation of more dental plaque, leading to greater problems.

Plaque forms in stages. Immediately after the teeth are cleaned, an adhesive layer of saliva, called an acquired pellicle, coats the teeth. Bacteria begin to attach to the pellicle shortly after it is formed, gradually spreading throughout the mouth and starting to multiply. As they form microcolonies, they secrete a slimy, protective layer that fosters their maturation. Brushing properly disrupts and removes this biofilm, but, when allowed to proliferate, plaque can build up and lead to disease. Plaque forms above the gumline first, forming in the grooves between the teeth, in the teeth themselves, and along the gumline. Bacteria then proliferates, moving downward into the crevices between the gums and the teeth. This subgingival plaque is difficult to remove and thrives in the anaerobic environment between the gums and the teeth, and the warm, moist environment of the mouth helps maintain the development of supragingival plaque, or plaque that forms above the gums. Different types of bacteria thrive in each of these different environments. The microorganisms in supragingival plaque are fed by sugars that come from the host’s diet, and, as these sugars ferment, they become acidic and cause dental caries, which are the cavities caused by tooth decay. The subgingival bacteria flourishes in the alkaline environment within periodontal pockets and closest to the alveolar bone. Together, they gradually destroy both.

When it is allowed to accumulate, plaque encourages inflammation of the gingival tissues by prompting the host’s immune system to respond to a bacterial invasion, leading to gingivitis. Symptoms of gingivitis include swollen, reddened gums and bleeding while brushing or cleaning interdentally, and gingivitis is reversible when detected early. If allowed to progress, gingivitis develops into periodontitis, which is characterized by destruction of the periodontal ligament that attaches the tooth to the alveolar bone. Periodontitis may also cause the bones that support the teeth to break down and may lead to tooth loss.

Everyone has plaque, and with proper hygiene, plaque can be managed well. When your dentist or dental hygienist cleans your teeth, they’ll use a dental instrument to assess the amount of plaque on your teeth. Dentists can also use disclosants, like tablets and gels, which can be applied to the teeth or chewed and which tint areas of plaque bright colors, usually pink, while clean areas remain white. These can be helpful clinical tools for dentists to assess the maturity of a patient’s plaque and also to help the patient see the areas they may want to focus on in the future.