Dental plaque is a biofilm of microorganisms (mostly bacteria, but also fungi) that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is often brown or pale yellow. It is commonly found between the teeth, on the front of teeth, behind teeth, on chewing surfaces, along the gumline (supragingival), or below the gumline cervical margins (subgingival). Dental plaque is also known as microbial plaque, oral biofilm, dental biofilm, dental plaque biofilm or bacterial plaque biofilm. Bacterial plaque is one of the major causes for dental decay and gum disease.Progression and build-up of dental plaque can give rise to tooth decay – the localised 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; hence it is important to disrupt the mass of bacteria and remove it. Plaque control and removal can be achieved with correct daily or twice-daily tooth brushing and use of interdental aids such as dental floss and interdental brushes.Oral hygiene is important as dental biofilms may become acidic causing demineralization of the teeth (also known as dental caries) or harden into dental calculus (also known as tartar). Calculus cannot be removed through tooth brushing or with interdental aids, but only through professional cleaning. Plaque formation
Dental plaque is a biofilm that attaches to tooth surfaces, restorations and prosthetic appliances (including dentures and bridges) if left undisturbed.
However, failure to remove plaque by regular tooth-brushing allows them to proliferate unchecked and thereby build up in a thick layer, which can by virtue of their ordinary metabolism cause any of various dental diseases for the host. Those microorganisms nearest the tooth surface typically obtain energy by fermenting dietary sucrose; during fermentation they begin to produce acids. The bacterial equilibrium position varies at different stages of formation. Below is a summary of the bacteria that may be present during the phases of plaque maturation:

Early biofilm: primarily Gram-positive cocci
Older biofilm (3–4 days): increased numbers of filaments and fusiforms
4–9 days undisturbed: more complex flora with rods, filamentous forms
7–14 days: Vibrio species, spirochetes, more Gram-negative organisms

Dental plaque as a biofilm
Dental plaque is considered a biofilm adhered to the tooth surface. It is a meticulously formed microbial community, that is organised to a particular structure and function. Plaque is rich in species, given the fact that about 1000 different bacterial species have been recognised using modern techniques.A clean tooth surface would immediately be colonised by salivary pellicles, which acts as an adhesive. This allows the first bacteria (early colonisers) to attach to the tooth, then colonise and grow. After some growth of early colonisers, the biofilm becomes more compliant to other species of bacteria, known as late colonisers. Early colonisers
mainly Streptococcus species (60–90%)
Eikenella spp. Haemophilus spp. Prevotella spp. Propionibacterium spp. Capnocytophaga spp. Veillonella spp. Late colonisers
Aggregatibacter actinomycetemcomitans
Prevotella intermedia
Eubacterium spp. Treponema spp. Porphyromonas gingivalisFusobacterium nucleatum is found between the early and late colonisers, linking them together.