What’s in the mouth, doesn’t stay in the mouth: How oral health links to systemic health


By Brian Mealey, DDS, MS, clinical professor, Periodontics

While the mouth is quite unique unto itself, it also has some similarities to other parts of the body.

Like the gastrointestinal tract, vagina and the conjunctiva of the eye, your mouth has a thin mucosal lining that acts as a first line of defense against infection. The mucosal lining is like the much thicker layer of skin we have. But there is an important difference between the mucosal lining in the mouth and other parts of the body.

When you get a sliver and have a break in your skin, a contaminated object pierces the formerly intact skin barrier, enabling bacteria, viruses and fungi that colonize your skin to access the tissues below the skin, including the blood vessels. When this happens, your body’s immune system will create an inflammatory response to ward off any invading pathogens. The difference between an interruption of the skin layer and the mouth is that breaking the skin barrier may happen on occasion. The mucosal lining in your mouth, however, is constantly interrupted by the presence of your teeth or dental implants.

The teeth are surrounded by the mucosa, and the junction between the tooth or implant and mucosa is very thin. It’s only a few cell layers thick. So, it doesn’t take much for bacteria to penetrate down the side of a tooth or down an implant to initiate an inflammatory reaction. When this happens, the white blood cells in your bloodstream migrate to the place where these teeth and implants are protruding through the mucosa and you get the classic signs of periodontal or gum disease including: inflammation, redness, swelling, bleeding and sometimes pain with flossing and brushing.

Even if your dental hygiene is perfect and there’s not a single bacterium left, within 12 hours, the bacteria will return. In this way, the mouth presents a constant cleansing battle. It’s really a balance between the bacteria normally supposed to be on the teeth and a biofilm, or microorganisms that situate on teeth like algae on a river rock. When we brush and floss, the goal is to remove that biofilm.

It’s important to note that the bacteria in the oral cavity do not stay there. If a patient has poor oral hygiene and a lot of biofilm and inflammation in the gum tissues, research has shown that those patients have a higher risk of having bacteria and their products enter the bloodstream and spread throughout the body.

The link between dental disease and systemic health is inflammation. The oral cavity is a huge store of inflammation. In fact, the surface area of the gums around the roots of your teeth affected by inflammation would be about the surface area of the palm of your hand or a tennis ball.

Diabetes has a strong link to gum disease.

With one in six San Antonians having type 2 diabetes — defined by an A1C percentage of 6.5% or higher — knowing the strong link between diabetes and periodontal disease is essential.

Type 2 diabetes is a disease of insulin resistance. The patient’s body is unable to use the insulin made in the patient’s pancreas effectively to control blood sugar levels. But the major cause of insulin resistance is inflammation. So why is it a goal for a type 2 diabetic patient to lose weight? One reason is that fat tissue is a major store of inflammation. When we lose weight, the amount of inflammation in our bloodstream decreases because we are losing fat mass and that decreases insulin resistance. Likewise, a patient who has both a bad case of gum disease and type 2 diabetes, not only has the insulin resistance they normally have which causes the diabetes, but now they have an inflammatory disease in the mouth where the inflammation does not stay in the oral cavity. Those inflammatory products spread throughout the bloodstream and further increase insulin resistance.

When the dentist or periodontist reduces that inflammation by removing the bacteria and their products from below the gum line, many studies show that treatment for periodontal disease leads to a decrease in oral inflammation and is associated with a subsequent improvement in blood sugar control. However, this does not mean every person will show improvement of blood sugar levels every time they receive treatment for periodontal disease.

Gum disease is a risk factor for heart disease and stroke.

While bacteria have access to blood vessels by other means than the teeth and gums, evidence strongly suggests that gum disease is a risk factor for adverse cardiovascular events, like heart attack and stroke. But the association of gum disease with cardiovascular disease does not mean that gum disease causes heart attack or stroke. Association is not causation.

Atherosclerosis, or hardening of the arteries due to a buildup of plaque, is a condition of inflammation. It starts with inflammation in the blood vessel lining. A number of studies have shown that if you have cardiovascular disease and you look at a large blood vessel in your neck, you often find thick atherosclerotic plaques. Some of those plaques will have bacteria in them. In patients with gum disease, those atherosclerotic plaques in their neck and blood vessels around their heart frequently contain bacteria from the oral cavity.

Adverse pregnancy outcomes linked to gum disease.

There is a large body of evidence that suggests that when pregnant women have gum disease, they are at increased risk for adverse events like pre-term delivery, or low-birth-weight infants. How could this happen? Because the bacteria from the oral cavity don’t stay in the oral cavity. They end up in the mother’s circulation and ultimately in the placental circulation. The resulting inflammation can play a role in adverse pregnancy outcomes.

Dental checkups at least every six months.

Unfortunately, most people don’t recognize gum disease because the bacteria are in a dark hole – the mouth. The only people who can go in there and treat the bacteria are dentists and dental hygienists.

To help maintain good oral care, it’s important to visit your dentist and hygienist every six months for a checkup and cleaning. If you have gum disease, you may need to be seen more often or referred to a periodontist, or gum specialist. Patients with conditions such as diabetes or other significant medical conditions may wish to see their dentist more often, but should at least follow the guidelines of every six months.

UT Health San Antonio’s General Dentistry Clinic provides patients a wide array of services from routine preventative care, cosmetic and restorative services to direct referrals to specialty practices within UT Dentistry, including periodontal assessments, oral surgery and much more.





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