• Teodora Todorova

Dental Plaque

Updated: Sep 3, 2019

What it is

Plaque is a thin and sticky film of bacteria that constantly forms on and between your teeth. These bacteria normally live in our mouths and find ingredients to grow in the food we eat and in the saliva. Everyone develops plaque.

Stages of plaque formation

  • Association – dental protein film forms on the tooth and provides the bacteria as surface to attach

  • Adhesion – within hours the bacteria loosely binds to the film

  • Proliferation – bacteria spreads throughout the mouth and begins to multiply

  • Microcolonies – small colonies are formed; streptococci bacteria secrete a protective slime layer

  • Biofilm formation – the microcolonies form complex groups that help them grow

  • Growth or maturation

Leaving plaque to stay on the teeth can lead to the two most widespread health conditions in the world - tooth decay (caries) and gum disease (periodontal diseases).

Caries (tooth decay)

When you eat foods with a high sugar and starch content, the bacteria stuck on your teeth turns those carbohydrates into acids. The acids in turn dissolve minerals in the hard enamel that covers the tooth's crown (the visible part of the tooth). As a result, the enamel erodes or develops pits, that are too small to see at first but increase in size over time.

The acid can seep through pores in the enamel, which is how decay begins in the softer dentin later, that is the main body of the tooth. A cavity is created. If the decay isn't treated, then the bacteria keeps growing and producing acid that eventually reaches the tooth's soft inner layer called the pulp, containing the sensitive nerve fibres. Tooth roots that are exposed from gum disease can also develop decay because the root's outer layer (cementum) is not a thick as the enamel.

The image above shows how the pH in the mouth drops drastically after sugar is eaten (lower pH means more acidic, which is when the bacteria start producing acids from the sugar) and then rises back up to normal. It is the saliva that acts to dilute and neutralise the acid and is an important natural defence against caries. It also provides minerals that help build back up (remineralise) the enamel that has been affected by the acids. It is when this balance is upset, that cavities start to form.


Your dentist will look at your teeth and may probe them with a tool called an explorer to look for pits or damaged areas. There is one problem in this method in that it often doesn't catch cavities in their early stages but may also puncture the enamel if too much force is applied.

Your dentist will also take X-rays of your teeth if a problem is suspected. This will show whether there's any newly forming decay, especially in between the teeth. More advanced decay can also be shown and whether it has reached the soft inner layer, and if so whether the tooth requires root canal treatment.


Tooth decay can be stopped in its early stages and can even be reversed. Fluorides and other prevention methods that form part of a good oral hygiene can help a tooth that is in the early stage of tooth decay to remineralise back to normal. White spots on the teeth are the last stage of early caries.

Once the condition becomes worse and there's a break in the enamel, only a dentist can repair the tooth. The standard treatment is to fill the tooth. If a drill is used, your dentist will numb the area. However, this is not needed, if a laser is used instead. Your dentist will remove the decayed material in the cavity and then fill the space. Fillings are usually made of dental amalgam (silver-grey) or composite resin (tooth colour), and newer resins tend to be very durable. Amalgams are generally used for the molars and premolars because the metal isn't easily seen at the back of the mouth.

If the cavity is large, then what's left of the tooth will not be able to support enough filling material to repair it. Instead, your dentist will remove the decay and cover the tooth with a ceramic inlay, onlay or artificial crown (these are made in a lab).

In general, having a caries increases your risk of more caries because:

  • It's caused by bacteria - the more decay you have then the more bacteria are multiplying in your mouth

  • The same oral hygiene and diet habits that caused your decay will lead to more decay

  • Bacteria tend to stick to fillings and other restorations more than to smooth teeth, increasing the chance of a new caries forming

  • Cracks or gaps in fillings may allow bacteria and food to enter the tooth, leading to decay from beneath the filling

Gum disease

If plaque isn't removed by brushing, it can harden into 'calculus' or 'tartar'. When this forms near the gumline, the plaque underneath releases poison causing the gums to get inflamed. The gums pull away from the teeth and the gaps become infected. If this problem is not addressed, the bone supporting the tooth is destroyed and the tooth can fall out. That is gum disease in a nutshell.

If you have gum disease, your dentist will usually give your teeth a thorough clean to remove any scale or tartar. They will show you how to remove soft plaque yourself. Gum disease is never really cured, but as long as you keep a good oral hygiene you can slow down its progress and even stop it. To do this you must make sure to remove plaque every day and check in with your dentist as often as they recommend.

Gum disease can also be factored by some lifestyle aspects you may not have considered:

Exercise - A recent study has also shown that people who stay fit and healthy are also 40% less likely to develop tooth-threatening gum infections. It also found that not exercising, being overweight and having unhealthy eating habits made it much more likely for a person to get advanced gum disease.

Smoking - smoking can make gum disease much worse. Smokers are more likely to produce plaque that leads to gum disease. Smoking means that less oxygen is supplied to your bloodstream, which affects the gums by not allowing them to heal properly.

Effects on health

There is evidence that in severe gum disease, bacteria from diseased pockets under the gums can enter the blood stream and trigger inflammation in other parts of the body. It is unclear yet whether these triggers are due to gum disease itself or other shared factors like lifestyle like smoking or being socially disadvantaged (increased risk of poor health in general). There are 2 main illnesses that gum disease is associated with:

Heart disease – bacteria from the mouth can enter the blood stream and may cause the development of fatty deposits in the heart vessels, called atheroma. Over many years this may lead to stiffer arteries and blocked arteries that can cause heart attacks and strokes in later life. However, this has not yet been proven without doubt.

Diabetes – severe gum disease seems to make diabetes harder to control or increases its complications in the heart and kidneys. The studies that have shown this are mainly small and limited in quality, however. On the other hand, high blood sugar levels in diabetes can also make gum disease worse.

Gum disease has two forms - Gingivitis and Periodontitis


Gingivitis is a condition where the gum tissue around the teeth is swollen and inflammed and as a result are more tender and prone to bleeding.

Early symptoms include:

  • red and swollen gums

  • bleeding gums after brushing or flossing your teeth

Advanced symptoms include:

  • bad breath

  • an unpleasant taste in your mouth

  • loose teeth that make it difficult to eat

  • gum abscesses (collection of pus that develop under your gums or teeth)

Acute necrotising ulcerative gingivitis (ANUG)

In rare cases of gingivitis, ANUG can suddenly develop, which is a more intense and painful version of the infection. Appropriate gum disease procedures will be done by your dentist to treat this. Treatment may include the use of antibiotics such as amoxicillin and metronidazole.

If ANUG isn’t treated it can lead to the gums in between your teeth being destroyed, and large ulcers that leave permanent holes in your gums. In rare cases, it can lead to gangrene affecting your lips, which when tissue starts to die and may need removal. If not treated properly the first time, ANUG is more likely to reoccur in the future.


Caused by periodontal bacteria and by the local inflammation triggered from those bacteria. Although the bacteria are naturally present in the mouth, it is only harmful when the conditions are right for it to multiply dramatically - having a built-up layer of plaque, especially in hard-to-reach areas (between teeth).

Periodontitis is a more severe form of gum disease and over the long term causes the bone supporting the teeth to break down. As a result of this, your gums may start to recede, pulling back from the teeth. Worst case scenario is that the bone supporting the tooth is destroyed, which leads to tooth loss. Some young adults have a very active form of the disease, causing early loosening and loss of the teeth.

Recognising it

  • increased bleeding of the gums (may be less noticeable in smokers due to nicotine's effect on blood vessels)

  • bad breath

  • changes in position of teeth

  • "lengthening" of teeth, which indicates gum recession

  • pain

Often it is not recognised by a person until they are 40 or 50 years old, by which time it's likely a lot of damaged has happened. This is why having dental check ups regularly is so vital.

Periodontitis treatment

  • Oral hygiene advice - your dentist will give you specific advice on how to keep your teeth and gums clean, the most appropriate way of brushing, the correct use of floss/interdental brushes, the right types of brushes for you, etc.

  • Professional cleaning - all soft bacterial deposits will be removed from accessible areas of the teeth and the teeth are polished and treated with fluoride; the next step would be removal of all plaque deposits and tartar from the root surfaces and gingival pockets

  • Antibiotic therapy - in some cases prescribed to deal with active or persistent gum infections that haven't responded to oral cleaning methods

  • Reassessment - several weeks after treatment, your dentist will make a full assessment of your gums to check the progress of the treatment; a periodontal probe is used to record the depth of any periodontal pockets and check for gum bleeding - further treatment may be needed if any pockets are still present

  • Corrective surgical treatment - more extreme cases require surgical procedures to clean plaque deposits under the gum within periodontal pockets and on the root surfaces at the furcations (where the roots diverge) - under local anaesthesia, the gum is lifted away and those root surfaces are cleaned to ensure all bacteria is removed; it's also possible to treat bone loss at the same time using a special regenerative treatment

Preventing gum disease

This comes down to basic oral hygiene - mainly, brushing your teeth (on all sides) twice a day, and using dental floss or interdental brushes to clean the spaces between your teeth.

You should take special care to clean well around crooked or crowded teeth and around fillings, crowns and dentures because plaque builds up easily in these hard to reach places.

Use disclosing tablets to temporarily stain the plaque on your teeth, so you can see it more easily when you brush and floss. This way you are sure to have cleaned your teeth properly.

Remember that plaque is sticky and because of this you have to brush and floss - rinsing your mouth alone won't help enough to remove the plaque and keep your teeth healthy.

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