Immunity and Dental Treatments

The concept of infection in the mouth influencing overall bodily health is nothing new. Over 2000 years ago Greek medics used to call the mouth the “great diagnostician” and Hippocrates was credited with curing illnesses by extracting infected teeth. In the 1890’s an American microbiologist and dentist, Willoughby D Miller, wrote a series of articles and papers on “The human mouth as a focus of infection’.

After years of searching for causes and associations, interest in the oral-systemic connection grew rapidly again in the 1980s and there have now been thousands of articles published since.

It is not, however, a simple concept and there is still a lot of work to be done in many areas. It is clear though, that we are once again putting the mouth back into the body, as it were, and beginning to understand that in making someone orally healthy we are significantly contributing to their general health and wellbeing.

Mechanisms and causality

Again we are really only beginning to fully understand how the oral systemic mechanisms work.
However the main focus is in 2 areas;

  1. Transposition of oral microbes to other parts of the body where these microbes can have a pathological effect on the tissues they are now in. So called ‘traveling oral microbes’ have been identified in the neck, atherosclerotic plaques in arteries, heart valve
    prostheses, thrombi that cause strokes and heart attacks, lungs, liver, gut, pancreas, joints and vertebrae, umbilical cord, placenta, breast milk and more!
  2. Inflammation in the mouth, principally the gum tissues, in response to plaque which then leads to a body-wide inflammatory response that can have significant effects on distant tissues. Uncontrolled chronic inflammation is a feature of many human conditions, local tissue inflammation, such as seen in the gum tissue responding to dental plaque, produces proinflammatory signals, chemical messengers that can then initiate the inflammatory response distant to the site of inflammation, such as interleukins, C  Reactive Protein (CRP), histamines and prostaglandins. This is highly significant in many oral-systemic connections. It is also worth noting that gum disease now ranks as the sixth most common human disease.

The diseases and conditions that have oral systemic connections may have processes that involve one or both of these mechanisms and as more data comes to light our understanding of this seems to improve daily.
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So which conditions have oral systemic links and how do they happen? The following isn’t an exhaustive list but gives a good representation of just what we are now seeing as the list grows.

Diabetes and Oral Health

It is very clear from the evidence we now have that diabetes and gum disease share a “two-way street” relationship. ( )Put simply, a patient that has both conditions is effectively locked into a spiral where the gum disease, now considered the sixth complication of diabetes ( ), worsens due to impaired healing, a change in host response and the oral microbiome and changes to the small blood vessels that supply the gum tissue. However we also now can show that the inflammatory process established in the gum tissue causes changes in the whole body inflammatory response which in turn leads to poorer glycaemic control, thus making it far more difficult for a diabetic to control their blood sugar levels. It is now thought that many patients with poorly controlled gum disease may be borderline or frankly diabetic and it is one possible method to diagnose the many patents out there with undetected diabetes. It wouldn’t be a huge step to see blood sugar levels being taken by dentists, especially gum specialists (periodontists) as part of a routine check-up one day in the not too distant future. Certainly for diabetic and pre-diabetic patients improving their oral health is a key part of helping to control their diabetes.
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Cardiovascular Disease and Stroke and Oral Health

There is now a consistent and strong body of evidence that links the presence of gum disease with an increased risk of cardiovascular disease and events such as heart attack and stroke. This association differs amongst different populations, age groups and socioeconomic groups but it is clear that this association is more than casual and that improving oral health is a key part of reducing the risk of cardiovascular events and that improving oral health as part of adopting a healthier lifestyle reduces this risk even further. ( ) ( )

One impact that poor oral health has is that the resulting inflammation of the gum tissue leads to the increased levels of pro-inflammatory chemicals such as cytokines and, as with diabetes, an increase in levels of c reactive protein, interleukins and other so-called inflammatory mediators. These can all contribute to an increased risk of atherosclerotic cardiovascular disease.( )

The second is found by looking at oral bacteria themselves. When gum tissue is inflamed it is a very poor barrier which is easily breached by many bacteria. These bacteria can get into the bloodstream, sometimes simply by brushing the inflamed tissue or even just by eating and chewing. This “bacteraemia’ as we call it means these bacteria can spread throughout the body. it can be seen that oral bacteria can colonize atherosclerotic plaques on the inside of blood vessels and their presence is implicated in destabilizing these plaques which, in turn, can lead to small parts breaking off as “thrombi”. It is these thrombi that block small vessels and cause heart attacks and strokes. Indeed oral bacteria have been found present in these thrombi in significant numbers and also in diseased heart tissue following a heart attack. ( ) ( )

In addition, oral microbes relocated to other parts of the body also increase the burden of systemic inflammatory responses that are thought to contribute to atherosclerosis and cardiovascular diseases. ( )

Adverse Pregnancy Events and Oral Health

For a long time there have been a lot of misconceptions and ‘old wives tales’ associated with pregnancy and oral health, While we do understand the increase in hormones during pregnancy can affect the gum tissues in multiple ways, this is always something that resolves postpartum. However we are now also discovering that, in women who have existing gum disease, poor oral health is now strongly associated with adverse pregnancy events such as preterm birth, low birth weight and preeclampsia. ( )

Again we see two mechanisms implicated in this. Firstly inflammation in the gums driving inflammatory responses elsewhere in the body via an increase in proinflammatory mediators and CRP and secondly a direct mechanism where oral bacteria gain access to the fetoplacental unit via the bloodstream and eliciting a negative response.  One study found that pregnant women with gum disease were almost seven times more likely to go preterm and others have now found oral bacteria present in the placentas of low birth weight and preterm babies. ( )  Given the growing evidence it is now clear that not only is oral health an integral part of general health, if you are planning to have a child or are pregnant, dental and oral care is an essential part of that plan. ( )

Alzheimer’s Disease and Oral Health

Studies have demonstrated that high exposure too inflammation below the age of 40 increases the risk of developing Alzheimer’s later in life. ( ) Studies on patients with Alzheimer’s demonstrate that those with active gum disease show a decline in cognitive function greater than those without. ( most recent investigations now also suggest that the bacteria that cause certain forms of gum disease are involved in the accumulation of toxic proteins in the brain, Beta-amyloid. ( ) Once again we see 2 mechanisms at work and like many associated conditions the more we discover the more we understand the integral role oral health has in maintaining physical well being.

Arthritis and Oral Health

The most recent data suggests the greater the tooth loss, a good marker for risk of gum disease may help predict rheumatoid arthritis (RA) and its severity. (
) The more teeth lost, the greater the risk. Observational studies throughout the 1990s demonstrated that those with RA showed more signs of gum disease and those patients with active gum disease showed more risk of RA. The relationship has been long suggested but its mechanisms poorly understood. Often it was implicated that simply by having less mobility, those with RA had poorer oral hygiene and therefore more risk of gum disease. But it is not that simple.

Research now shows a likeness in the inflammatory processes involved in both RA and gum disease and specific markers can be detected that show a 2 way relationship based around inflammation, similar to that of diabetes and also a suggestion that antibodies created in response to certain oral bacteria could even trigger RA. ( )

While there is still more to understand the message is clear; if you have RA, take care of your oral health and schedule regular hygiene visits and check-ups!

Obesity and Oral Health

This is a relationship that again is complex and has many factors, many of which are simply associated with poor lifestyle. However, one study showed that patients with a BMI of over 30, regardless of smoking or diabetes status, showed a greater risk of developing gum disease and a similar trend as waist circumference and waist to hip ratio increased. ( ) The exact mechanism is still to be proven but fat tissue is believed to promote a proinflammatory state and that then, by ways we have already discussed, increases the risk of gum disease and other inflammatory linked conditions. Also it is currently thought that changes in diet associated with obesity lead to changes in the oral bacteria population and that may then further contribute to the link between the two. ( )

Pneumonia and Oral Health

Poor oral hygiene allows the development of dental plaque. Dental plaque is a complex mix of proteins, a biofilm and bacteria of many and various kinds that develops on the dental tissues. As plaque matures it can become colonized by bacteria that can cause respiratory infections. Bacteria isolated from lung aspirates in patients with suspected pneumonia have been shown to be genetically identical to those on the mouth of the same patient. ( ) Improved oral hygiene has been shown to contribute to the prevention of pneumonia in hospital and nursing home patients, the patients who are most at risk of this complication. ( )


There can be no doubt that improving and maintaining your oral health is now a key element in maintaining your overall health and wellbeing. Here at Dr Roze and Associates we have a dedicated team who recognize that we are always treating a patient, not just a mouth, and who strive to deliver the very best standard of care to you for all the right reasons. Healthy mouth, healthy body, healthy mind, That’s why we love to see you smile.

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