Periodontology – Plaque

Dental plaque is a collection of bacteria, or biofilm, which grows on various surfaces inside the mouth. Plaque is sticky and colorless in the early stages. However, once tartar forms, it can turn to brownish or pale yellow color. Tartar typically exists between the teeth, on the front or back surfaces of the teeth, on chewing surfaces, along the gumline or below the gumline. Additional terms which are used for dental plaque include microbial plaque, oral biofilm, dental biofilm, dental plaque biofilm and bacterial plaque biofilm. Bacterial plaque is a main causes for gum disease and tooth decay.

When plaque is able to build-up and collect over time, it can ultimately cause tooth decay. Acid, which is produced from the bacterial degradation of fermentable sugar, destroys the teeth’s tissues. This can also result in periodontal problems including gingivitis and periodontitis. It is critical to disrupt and properly remove the bacteria. Twice daily brushing and daily flossing aid in preventing and removing plaque.

Because dental biofilms can become acidic and cause the demineralization of the teeth, oral hygiene is especially important. The demineralization of the teeth is also called dental caries. These biofilms are also to harden into dental calculus or tartar, which require a professional cleaning to remove.

Formation of Plaque

Dental plaque is a biofilm which attaches to surfaces of the teeth, restorations and prosthetic appliances when it remained undisturbed. In order to keep it under control, it is important to understand how plaque forms, in addition to the composition and characteristics. An acquired pellicle is a layer of saliva, which is primarily comprised of glycoproteins. It forms shortly after the cleaning of teeth or when new teeth erupt. Bacteria will attach to the pellicle layer, form micro-colonies, which are able to grow and mature, and can ultimately cause oral diseases.

Plaque Components

It is normal for various types of bacteria to exist within the mouth. These bacteria contribute to a healthy oral cavity and good overall health for a patient. About 80–90% of the weight of plaque is made up of water. Nearly 70% of the dry weight is from bacteria and the remaining 30% is from polysaccharides and glycoproteins.


Most of the microorganisms which cause the formation of biofilm are Streptococcus mutans (S. mutans) and other anaerobes. The precise composition of biofilm will vary based on its specific location in the mouth. The first colonizers of the surface of the teeth are S. mutans and other anaerobes. They play a critical role in the establishment of the initial biofilm community. These microorganisms are all naturally present in the oral cavity and typically do not cause any harm. When patients fail to effective remove plaque through regular tooth-brushing, however, it allows the microorganisms to proliferate and establish a thick and prominent layer on the teeth. This can cause various different oral issues. The microorganisms closest to the surface of the teeth typically obtain their energy through the fermentation of dietary sugars. Destructive acids are then produced during the fermentation process.


The following are some of the most common consequences of the build-up of plaque for patients:

  • Gingivitis
  • Periodontitis
  • Disease, including diabetes, cardiovascular and respiratory diseases