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Dental Plaque


1. What is plaque? What is tartar?

Dental plaque is a sticky deposit or biofilm of micro-organisms, mainly bacteria, often colorless, which constantly forms on the surface of teeth, especially at the junction with the gums, on restorations and on prostheses (including bridges and dentures). 

This plaque, also called bacterial plaque, is formed from food residues that are not removed by brushing (especially sweet foods) and from concretions brought by saliva.

Without regular brushing, bacteria proliferate, creating successive, organized layers that become more and more resistant. Plaque begins to form 4 to 12 hours after brushing. This is why it is important to brush your teeth at least twice a day and to use brushes or dental floss to "disorganize" the structure that is forming.



When it is not removed, the plaque mineralizes into a layer of tartar, yellowish or even brownish in color. This layer, which is more difficult to remove, will not be removed by brushing but by scaling at your hygienist or dentist.


Diagram: Proliferation of oral bacteria on the surface of a tooth


2. Why to eliminate dental plaque?

It is important to eliminate dental plaque and tartar because the accumulation of bacteria on the surface of the tooth followed by their migration under the gum is the cause of 2 major oral health problems 

  • on the surface of the tooth, dental caries due to the acids produced by bacteria (streptococcus mutans) during the transformation of sugars contained in food residues; the repeated acid attacks destroy the enamel and form a cavity in the tooth: the caries

  • periodontal diseases in the periodontium and gums due to the imbalance between the bacteria (proteobacteria) and pathogens (streptococci or granulicatella):

    • gingivitis with irritation of the gums (red, swollen, bleeding easily),

    • periodontitis with the loosening of the tooth (gingival recession) or even the loss of the tooth after attacking the bone.


In addition to the aesthetic problem of the color of the surface of your teeth, bacteria can cause bad breath (halitosis).

3. How to avoid the formation of dental plaque?

The best way to avoid the formation of dental plaque is to

  • brush your teeth 2 to 3 times a day for at least 3 minutes with a toothbrush (ideally electric) and a suitable toothpaste. and

  • use interdental brushes (with a little toothpaste on the surface) and/or dental floss to remove residues from hard-to-reach areas (usually once a day, in the evening).


Indeed, these two actions, which correspond to both a mechanical action of the toothbrush/brushes and a chemical action of the toothpaste, will reduce/eliminate and disorganize the dental plaque and thus prevent its development, thus controlling the proliferation of pathogenic micro-organisms.


The evening brushing is particularly important because the positive action present during the day (salivation, speech, tongue movements) is no longer present.

4. More info on the bacteria present in the mouth

The mouth is the seat of an important microbiota comprising billions of micro-organisms, in particular nearly 700 species of bacteria, some beneficial such as Streptrococcus sanguinis which prevents cavities, others pathogenic. This oral flora is built from birth, throughout life and varies from one individual to another depending on his diet, his oral hygiene, his age and other factors (temperature, pH of saliva, etc. ...).

The main thing is to maintain the balance of the microbiota (eubiosis) between these populations. Saliva, which plays several roles, strongly contributes to this; indeed, it allows to "rinse" the food remains and the thin film of saliva which covers the teeth, protects them against bacteria and their acid attacks. In addition, the antimicrobial agents present in saliva kill pathogenic bacteria. 

To simplify, when the microbiota is in balance, beneficial bacteria colonize all the surfaces of the mouth, leaving little room for the attachment and therefore the proliferation of pathogenic agents.

However, disruptions in this balance (dysbiosis) can occur as a result of poor oral hygiene, tobacco, alcohol, stress or diseases such as diabetes. 

Indeed, if we do not eliminate the food residues that remain in the mouth (on the teeth, the gums, the tongue), certain pathogenic bacteria feed on them; this is the case of Streptococcus mutans, which creates dental plaque.

See Question 3 to understand the negative impact of dental plaque.

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