Dental plaque

Refers to a complex mass of microorganisms of oral flora, salivary proteins, and desquamated epithelial cells.

Dental plaque is also known as dental biofilm.


Dental plaque is a sticky, yellow film consisting of a  range of bacteria which attaches to the tooth surfaces and can be visible around the gum line. 


Only a limited set of microbes cause tooth decay, with most of the bacteria in the human mouth being harmless. 


Tooth decay is an infectious disease:  increased within dental plaque of bacteria such as Streptococcus mutans and Lactobacillus. 

These organisms produce organic acids when carbohydrates, especially sugar, are eaten.


When enough acid is produced to lower the pH below 5.5,  the acid dissolves carbonated hydroxyapatite, the main component of tooth enamel, in a process known as demineralization.

Accumulation of dental plaque is a major risk factor for caries and periodontal diseases.

The ineffective removal of dental plaque leads to bacterial colonization and tissue damage in the oral cavity.

Dental plaque initiates periodontal disease as well as a systemic inflammatory response.

Daily oral care may affect the initiation and progression of chronic inflammatory processes, including cardiovascular disease.

Inflammation plays a significant role in the pathogenesis of atherosclerosis and can be measured by high sensitivity C reactive proteins, a sensitive marker for cardiovascular disease.

Refers to a biofilm or mass of bacteria that grows on surfaces within the mouth.

Also known as microbial plaque, oral biofilm, dental biofilm, dental plaque biofilm or bacterial plaque biofilm.

Plaque is a sticky colorless deposit when it forms as tartar.

Then becomes brown or pale yellow.

Plaque is commonly found between the teeth, on the front of teeth, behind teeth, on chewing surfaces, along the gumline, or below the gumline.

Dental plaque progression can give rise to tooth decay.

Dental plaque buildup causes localized destruction of the tissues of the tooth by acid produced from the bacterial degradation of fermentable sugar, and periodontal problems such as gingivitis and periodontitis.

A high-sugar consumption encourages the formation of plaque. 


Sugar (fermentable carbohydrates), is converted into acid by the plaque. 


The acid then causes the breakdown of the adjacent tooth, eventually leading to tooth decay.

It is important to disrupt the mass of bacteria and remove it.

Dental plaque can be controlled and removed can with correct daily or twice-daily tooth brushing and use of interdental aids such as dental floss and interdental brushes.

When dental biofilms become acidic causing demineralization of the teeth, known as dental caries, or harden into dental calculus, known as tartar.

Calculus is cleared only through professional cleaning.

If calculus is not treated, the inflammation will lead to the bone loss and will eventually lead to the affected teeth becoming loose.

In plaque formation an acquired pellicle layer of saliva, composed of mainly glycoproteins.

This pedicle forms shortly after cleaning of the teeth.

Bacteria subsequently attach to the pellicle layer, form micro-colonies, and mature on the tooth, resulting in oral diseases.

Different types of bacteria as well as leukocytes, neutrophils, macrophages, and lymphocytes, are part of the normal oral cavity and contribute to health.

Approximately 80–90% of the weight of plaque is water.

Approximately 70% of the dry weight of dental plaque is bacteria.

Approximately 30% of dry dental plaque consists of polysaccharides and glycoproteins.

The bulk of the microorganisms that form the biofilm are Streptococcus mutans and other anaerobes.

Microorganism composition varies by location in the mouth.

Anaerobes include fusobacterium and actinobacteria.

Anaerobes are the initial colonizers of the tooth surface.

Anaerobes play a major role in the establishment of the early biofilm community.

Anaerobe microorganisms are naturally present in the oral cavity and are normally harmless.

Failure to remove plaque by regular tooth brushing allows such microorganisms to proliferate and build up in a thick layer.

The microorganisms ordinary metabolism cause various dental diseases for the host.

Microorganisms nearest the tooth surface typically obtain energy by fermenting dietary sucrose.

During fermentation microorganisms begin to produce acids.

Toothpaste with fluoride, or alternatives such as nano-hydroxyapatite, is an important to use when tooth brushing. 



The fluoride in the dentifrice is an important protective factor against caries, and an important supplement needed to remineralize already affected enamel.

The early biofilm contains primarily Gram-positive cocci

A 3-4 day old biofilm has increased numbers of filaments and fusiforms.

An undisturbed 4–9 days old biofilm contains more complex flora with rods, and filamentous forms.

At 7–14 days Vibrio species, spirochetes, more Gram-negative organisms are added.

The first kind of plaque to form after the brushing of the teeth is a supragingival biofilm that forms above the gums.

Gum disease is caused by a sticky film of bacteria-plaque. 



Plaque is always forming on teeth, but if it is not cleaned well, the bacteria in plaque can cause gums to become inflamed. 


When this happens, the gums pull away from the teeth and form spaces called pockets. 


Plaque then gets trapped in these pockets and cannot be removed with regular brushing. 


Untreated gum disease can lead to bone and tooth loss.


If the periodontal pockets are too deep a deep cleaning  Y scaling and root planing is necessary to remove the plaque in these pockets.

The supragingival plaque commonly forms in between the teeth, in the pits and grooves of the teeth and along the gums.

The supragingival plaque is made up of mostly aerobic bacteria.

Subgingival biofilm plaque is located under the gums.

Subgingival biofilm plaque begins to form after the formation of the supragingival biofilm by a downward growth of the bacteria from above the gums to below.

Subgingival biofilm plaque is mostly made up of anaerobic bacteria, which will only survive if there is no oxygen.

Subgingival biofilm plaque attaches in a pocket under the gums, and since they are not exposed to oxygen in the mouth will therefore thrive if not removed.

The extracellular matrix of the subgingival biofilm plaque contains proteins, long-chain polysaccharides and lipids.

Subgingival biofilm plaque leads to opportunistic pathogens which may cause dental caries and periodontal disease.

Pathogenic bacteria that have the potential to cause dental caries flourish in acidic environments.

Pathogenic bacteria that have the potential to cause periodontal disease flourish in a slightly alkaline environment.

The mouth is able to support the growth and development of dental plaque due to its moist and warm environment.

Factors that contribute to plaque formation are pH, saliva, temperature and redox reactions.

The normal pH range of saliva is between 6 and 7.

Plaque biofilm is known to flourish in a pH between 6.7 and 8.3.

The natural environment of the mouth provided by saliva is ideal for the growth of bacteria in the dental plaque.

Saliva acts as a buffer, which helps to maintain the pH in the mouth between 6 and 7, and contains nutrients including amino acids, proteins and glycoproteins.

These nutrients feed the bacteria involved in plaque formation.

Diet plays only a minor role in providing nutrients for the resident microflora.

The normal temperature of the mouth ranges between 35 and 36 °C, and a two-degree change can shift the dominant species in the plaque.

Aerobic bacteria redox reactions keeps the oxygen levels in the mouth that allow bacteria to survive.

Bacteria in the biofilm elicit a localized inflammation of the tissue, characterized by a red, puffy appearance of the gums and bleeding due to brushing or flossing.

Gingivitis secondary to plaque can be reversed by removal of the plaque.

If gingivitis is left for an extended period, the inflammation may affect the supporting tissues, as periodontitis.

Periodontitis, an infection of the gums leads to bone destruction around the teeth in the jaw.

Not all individuals who have gingivitis will get periodontitis.

Plaque accumulation causes the progression of periodontitis as the bacteria in plaque release enzymes which attack the bone.

Dental caries is an infectious disease caused primarily by Streptococcus mutans.

Dental caries is manifested by acid demineralization of the enamel, which can progress to further breakdown of the more organic, inner dentin.

Factors for developing carious lesions on the teeth include:

Low fluoride exposure

Time, length, and frequency of sugar consumption

Quality of tooth cleaning

Fluctuations in salivary flow rates and composition

Behavior of the individual

Socioeconomic status of the individual.

Quality and composition of biofilms.

Organic acids from dental plaque lead to demineralization of the adjacent tooth surface, and consequently to dental caries.

Saliva is unable to penetrate plaque and cannot act to neutralize the acid produced by the bacteria and remineralize the tooth surface.

The main methods of detecting dental plaque is through the application of a disclosing gel or tablet, and/or visually through observation.

Plaque detection is usually detected by plaque disclosing agents containing dye which turns bright red to indicate plaque build-up.

Plaque disclosing products, also known as disclosants, make plaque clinically visible.

Only rough surfaces absorb the disclosant

These gels provide a visual aid in assessing plaque biofilm presence and maturity.

Disclosing tablets are similar to disclosing gels, except that they are placed in the mouth and chewed on for approximately one minute.

Dental biofilm begins to form on the tooth only minutes after brushing.

The average brushing time for individuals is between 30 seconds and just over 60 seconds.


Tooth brushing should be done for a minimum of two minutes, and be practiced at least twice a day.


Toothbrushing can only clean to a depth of about 1.5 mm inside the gingival pockets

A sustained regime of plaque removal above the gum line can affects the microbes below the gums and may reduce the number of pathogens in pockets up to 5 mm in depth.

Dental plaque can be felt as a rough surface, and is often felt as a thick, fur-like deposit that may present as a yellow, tan or brown stain.

Dental plaque deposits are commonly found on teeth or dental appliances such as orthodontic brackets.

The most common areas where plaque is found is between the teeth and along the cervical margins.

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