Dental plaque

Tiny germs live in your mouth.

They stick to your teeth. They make a sticky, clear layer. This layer is called plaque.

When you eat sugar, the germs use it. This makes them make acid. The acid can hurt your teeth. It can cause holes in them.

Plaque can also hurt your gums. Your gums might look red and puffy. They might even bleed.

If you do not clean it, plaque gets hard. This hard stuff is called tartar. You cannot brush tartar away.

You can brush your teeth twice a day. You can also use floss. This helps keep your mouth healthy.

Tiny living things live in your mouth. They form a sticky, clear layer on your teeth. This layer is called dental plaque.

It is a biofilm. A biofilm is a group of germs that live together in a community.

Plaque forms in a few steps. First, a thin layer of saliva forms on your tooth. This is called a pellicle. Next, bacteria stick to this layer. Soon, the bacteria multiply and form small groups. These groups grow into a thick layer.

Some bacteria, like Streptococcus mutans, use sugar to make a sticky substance. This helps the plaque stay on your teeth. When bacteria eat sugar, they make acid. This acid can cause dental caries. This is the medical name for tooth decay.

Plaque can also hurt your gums. It can cause gingivitis. This makes your gums look red and puffy.

If you do not clean it, plaque can turn into tartar. You cannot brush tartar away. You must see a professional for cleaning. Brush twice a day and use floss to stay healthy.

Dental plaque is a sticky, colorless layer that grows on the surfaces of your teeth. It is a biofilm, which is a community of many tiny living things like bacteria and fungi.

You can find plaque between your teeth or along your gumline. It might also hide on the chewing surfaces or behind your teeth. If you leave it alone, it can harden into something called tartar. Tartar is often brown or pale yellow in color.

It is very important to remove this buildup to keep your mouth healthy.

Plaque forms through a specific set of steps. First, a thin layer of saliva called a pellicle forms on the tooth. This layer acts like a glue for bacteria to attach to. Within hours, bacteria bind to this pellicle and begin to multiply. These bacteria form small groups called microcolonies. Some bacteria, like Streptococcus, even create a protective slime layer. Eventually, these groups grow into a complex biofilm.

This biofilm can even develop a primitive way to move nutrients around.

Many different types of bacteria live in this community. About 80% to 90% of the weight of plaque is actually water. The rest is made of bacteria, sugars, and proteins. One main type of bacteria is called Streptococcus mutans. These bacteria use an enzyme to turn sucrose, or table sugar, into a sticky substance. This helps the plaque stick tightly to your teeth. Other bacteria, called anaerobes, prefer to live in places without much oxygen. These often grow in the plaque found under your gums.

If plaque is not cleaned away, it can cause several problems. One problem is dental caries, which is the medical name for tooth decay. This happens when bacteria eat sugar and produce acid. The acid can damage the hard parts of your teeth. Plaque can also cause gingivitis, which makes your gums look red and puffy.

If gingivitis is not treated, it can turn into periodontitis. This is a serious infection that can destroy the bone around your teeth.

Keeping your teeth clean is a simple way to stay healthy. You can disrupt the bacteria by brushing your teeth twice a day. Using dental floss or interdental brushes also helps reach tight spaces. Brushing is great for removing soft plaque, but it cannot remove hard tartar. If tartar forms, you will need a professional cleaning to get it off. Regular care helps prevent the acid and infections that lead to tooth decay. Taking care of your mouth helps your whole body stay well.

Dental plaque is a complex microbial biofilm that grows on surfaces within the mouth. It is a sticky, colorless deposit that can eventually harden into dental calculus, also known as tartar.

This biofilm is a highly organized community of microorganisms, including bacteria and fungi. It attaches to tooth surfaces, dental restorations, and prosthetic appliances like dentures or bridges. Because plaque is a major cause of dental decay and gum disease, understanding its biology is essential for maintaining oral health.

The formation of plaque occurs through a specific sequence of biological steps. First, an acquired pellicle forms on the tooth surface. This is a layer of saliva composed mainly of glycoproteins that appears shortly after cleaning. Within hours, bacteria undergo adhesion, loosely binding to this pellicle layer. Next, the bacteria begin proliferation, spreading and multiplying throughout the mouth. They then form microcolonies, where species like Streptococcus secrete a protective slime layer. Finally, these microcolonies develop into a mature biofilm that can even possess a primitive circulatory system.

Different types of bacteria dominate the plaque at various stages of its development. The early biofilm consists primarily of Gram-positive cocci, such as Streptococcus species, which make up 60% to 90% of the early colonizers. As the biofilm matures over 3 to 4 days, the number of filaments and fusiform bacteria increases. By 7 to 14 days of undisturbed growth, the community becomes more complex, including Vibrio species, spirochetes, and more Gram-negative organisms. Some bacteria, known as late colonizers, such as Porphyromonas gingivalis, join the community later. Fusobacterium nucleatum plays a vital role by linking the early and late colonizers together.

Plaque is categorized by its location in the mouth, which changes its composition. Supragingival biofilm forms above the gumline in areas like the pits, grooves, and spaces between teeth. This type of plaque is mostly made of aerobic bacteria, which require oxygen to survive. In contrast, subgingival biofilm forms below the gumline in the pockets of the gums. This environment lacks oxygen, allowing anaerobic bacteria to thrive.

This downward growth from the supragingival area to the subgingival area is a key part of how plaque progresses.

The chemical makeup of plaque is quite specific. Approximately 80% to 90% of the total weight of plaque is water. Of the remaining dry weight, 70% consists of bacteria, while 30% is made of polysaccharides and glycoproteins. A key player in this ecosystem is Streptococcus mutans. This bacterium uses an enzyme called glucansucrase to convert sucrose into a sticky, extracellular, dextran-based polysaccharide. This process allows the bacteria to cohere and stick firmly to the tooth.

If plaque is not removed through regular brushing and flossing, it leads to several health issues. One consequence is dental caries, or tooth decay. This is the localized destruction of tooth tissues caused by acid produced during the bacterial degradation of fermentable sugar. Another result is gingivitis, an inflammatory response where the gums appear red and puffy.

If left untreated, gingivitis can progress to periodontitis. This is a serious infection that leads to the destruction of the bone supporting the teeth.

In periodontitis, bacteria release enzymes that attack the bone, while cells called osteoclasts also break down bone to prevent the spread of infection.

The oral environment provides a unique setting for these microorganisms. Unlike other parts of the body, tooth surfaces are hard and do not shed. The mouth is warm and moist, which is ideal for bacterial growth. Saliva acts as a buffer to maintain a pH between 6 and 7, and it provides nutrients like amino acids and proteins. However, when bacteria ferment dietary sucrose, they produce acids that lower the pH. This acidity can cause demineralization of the enamel. Furthermore, the mouth's temperature, usually between 35°C and 36°C, can shift dominant species if it changes by even two degrees.