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The defences of the mouth

June 10, 2019

Sorry to say this, the mouth is a dirty place. It’s teeming with bacteria and fungi. How does the human race survive?!

The organisms happily live on the surfaces of the mouth without upsetting the body. Remember the mouth and the rest of the digestive system is essentially outside the body. We breathe, eat, drink, swallow, and taste the outside environment. So a lot of unwelcome visitors are arriving.

We survive because of the body’s immune system.

The mouth - ready for breathing, eating, tasting and swallowing

Saliva defence

Salvia is crucial to keeping the mouth healthy. It contains antibodies that are unique to saliva called IgA (immunoglobulins type A). Without saliva we cannot control the decay. Radiotherapy of the head causes the salivary glands to stop working and decay can occur rapidly if extreme care is not done!


Gingival Fluid defence

The gums around the tooth have a little gap called the gingival sulcus. Fluid leaked out of the blood vessels in the gums, contains white blood cells. These cells leak out of the gingival sulcus to fight germs on the surface of the teeth. This is great mechanism, however the germs on the teeth absorb calcium out of the saliva and form the hardened mass called calculus, or tartar.

This mass can harbour anaerobic bacteria which are more aggressive as they release anti immune enzymes. The answer is to clean calculus off the tooth as the body cannot do this itself.

Left: Plaque and calculus build up; Right: After scale and clean much better

As the body immune system relies on the general health of the body, sometimes simple gum problems become major issues.

Acute necrotizing gingivitis (ANUG) is example of severe compromised immune system due to poor diet, nutrition and living conditions (like in the trenches during the war). The body just can’t cope and the infection is unchecked and the gingival sulcus area starts to die!

Trench Mouth of the past or ANUG of today

Medical conditions such as uncontrolled diabetes weaken the effectiveness of the white blood cells as they have reduced energy.

Medications and hormones can alter the immune response as well. This can be seen as an overgrowth of the gums in response to the bacteria on the teeth.

Blood/bone defence

This is the full body range of the body’s defences in the bone and in the beneath the soft tissue. White blood cells have other allies in the form of antibodies. These include IgG, IgM and in conjunction with T-cells and B-cells fight infections from not only bacteria, and fungus but also viruses and parasites. This immune response is compromised in diseases such as AIDS.

Root canal treatment is designed to remove dead tissue and bacteria within the roots. The body can’t do this without blood vessels. Sometimes the immune system will eat the tooth away to get at the infection, called resorption! Otherwise we remove the tooth.

The fluid that leaks out of the blood vessels ends up eventually into the lymph system and then onto to the Aorta. Along the way there are lymph nodes, which are collections of immune cells that fight infection here as well that drain from the mouth. These are found just below the lower jaw and in the neck.

Pus is a situation that means the body is throwing everything at the infection. The blood vessels and the tissue begin to die. The dentist sometimes needs to drain the pus to allow the blood vessels to return. The blood carries the immune cells and products as well as antibiotics.

Pus draining through a root canal
Blood vessels mean healing can occur!

Need an Appointment?

If you’d like to book an appointment with the dentist at Seymour Dental then call us in Dulwich Hill, Sydney on (02) 9564 2397 or
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Next week

Gastric Reflux by Dr Esther