Oral and Systemic Health: Treating the Whole Patient

/Home/Dental Care and Medical Concerns

Oral and Systemic Health: Treating the Whole Patient
September/October 2007
Barbara L. Bennett, CDA, RDH, MS
Contemporary Dental Assisting

Abstract

The evidence is mounting that oral health is strongly related to overall health. Research is linking the chronic inflammation of periodontal diseases with many other diseases, such as heart disease, respiratory disease, poor maternal and fetal outcomes, diabetes, and certain types of oral cancer. The long-term inflammation in chronic periodontal diseases is believed to trigger and intensify these systemic diseases, and to make management of some, such as diabetes, much more difficult. Dental assistants play a vital role in patient assessment and education, and can be a strong influence in health promotion in their clinical practices.
Learning Objectives

After reading this article, the reader should be able to:

* describe the associations between periodontal diseases and systemic diseases, such as diabetes, cardiovascular disease, premature and low-birth-weight babies, respiratory diseases, and cancer.
* apply information linking periodontal diseases and systemic health to maximize patient motivation and case acceptance.
* promote overall health by helping patients improve their oral health.

While the eyes may be the "window to the soul," the mouth may be a mirror of the body. The relationship between oral health and overall health was linked by many early 20th-century dentists and physicians. The focal theory of infection was proposed by Willoughby D. Miller in 1891, and many proponents of this theory advocated extraction of all teeth to cure other bodily ailments. In 1928, Dr. Charles Mayo stated that infected tonsils and teeth can explain almost all infectious diseases, and proposed that dentistry become a specialized branch of medicine. But in the 1950s, as scientific methods and research improved, the focal theory of infection fell into disfavor, and physicians and dentists once again went their separate ways.1

Hundreds of studies since the late 1980s have found correlations between periodontal diseases and systemic diseases such as diabetes, obesity and heart disease, respiratory disease, poor birth outcomes, and even some types of cancer. This article will discuss the relationships between periodontal diseases and these systemic diseases.
Obesity, Type 2 Diabetes, and Periodontal Diseases

The relationship between periodontal diseases and diabetes has been shown to be a 2-directional relationship, with the worsening of either of the 2 conditions having a negative effect on the other. In the 1960s, National Institutes of Health (NIH) researchers discovered that nearly half of the Pima people of Central Arizona over the age of 35 had type 2 diabetes, 8 times the national average. The NIH researchers also found that the Pimas had other health problems, such as kidney and heart disease. By the early 1980s it was established that the Pimas with diabetes had twice as many periodontal diseases as the general population, and the level of disease was more severe. One of the principal researchers noted that obesity in patients with diabetes was linked to both difficulties in controlling the diabetes and progression of periodontal diseases at a greatly increased rate.

Fat cells can produce toxic cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), that can increase insulin resistance and blood glucose levels and break down bone and the linings of the blood vessels. These conditions can lead to heart disease and stroke.2-8 The relationship between obesity and type 2 diabetes has been well documented, but the 3-way relationship between obesity, diabetes, and periodontal diseases is just starting to be explored. The same mechanism that causes insulin resistance and elevated levels of proinflammatory cytokines, such as TNF-α, also plays a role in the destruction of alveolar bone and connective tissue in periodontitis.2,3,9

While diabetes can increase the risk of periodontal diseases, patients with diabetes who also have periodontitis have a more difficult time controlling their glucose levels compared with those without periodontitis. This difference is especially dramatic among children. Both gingivitis and periodontitis (uncommon in children without diabetes) are more severe in children with diabetes compared with those without the disease.10-12 The strong relationship between the 2 diseases is probably because of the advanced glycation end products (AGEs)Ûthe end result of long-term hyperglycemia on the red blood cellsÛwhich transform the usually protective inflammatory cells into producers of highly toxic substances, damaging other body systems besides the periodontium. The damaged tissues secrete more toxic byproducts, and the cycle of destruction continues. Reducing the inflammation with improved periodontal health can short-circuit the cycle of damage.

Other interesting (and deadly) changes occur when blood sugar is continually elevated. The neutrophils, our first line of defense against infection, become impaired and are unable to locate the site of infection, so the rest of the protective effect is not activated swiftly. This could account for the 2 to 4 times greater risk of severe bone loss seen in patients with uncontrolled diabetes. Severe periodontal infections are considerably more common in patients with type 2 diabetes, and the chronic nature of these infections further diminishes the patient's ability to control blood glucose levels. Numerous studies have demonstrated that periodontal therapy can result in a significant reduction in AGEs, and improved glycemic control.3-5,13

Dental assistants can reinforce the importance of periodontal health in the overall control of diabetes by educating patients on the link between infections in the mouth and worsening of diabetes. Another valuable service dental assistants can perform is being alert for clinical signs of undiagnosed diabetes, such as sudden onset of severe gingival and periodontal diseases, burning mouth or tongue, changes in taste, candidiasis, and development of abscesses. These signs and symptoms should be brought to the dentist's attention for the possibility of referral to a physician for further exploration.5,13
Flossing Is Good for the Heart

The initial correlation between oral and systemic health showed up when researchers in the 1980s noted an increased number of heart attacks in persons with severe periodontal diseases.14 Since that time, evidence has been growing that atherosclerosis (hardening of the arteries) is a chronic inflammatory condition caused by infectious agents. The chronic inflammation caused by periodontal diseases increases the inflammatory chemicals, such as C-reactive protein (CRP) and fibrinogen, both of which are elevated in people with cardiovascular disease (CVD). Fibrinogen is a clotting factor that is associated with the formation of thrombi or clots that block the blood vessels and cause heart attacks and strokes. TNF-α, found in patients with chronic periodontal diseases, increases the liver's production of triglycerides and lowers the levels of high-density lipoprotein (the "good" cholesterol), increasing the risk of coronary heart disease. Patients who had a 20% increase in bone loss caused by periodontal diseases showed a 40% increase in development of chronic heart disease. It is not just the general inflammatory response that is to blame for the increases in CVDÛindividual periodontal pathogens found in bacterial plaque also can cause direct damage to the coronary arteries if they travel from the infected periodontal pockets into the bloodstream. When athermanous lesions (fatty plaque buildups) in the carotid and coronary arteries were studied, more than 40% of the lesions contained antigens from periodontal pathogens, such as Porphyromona gingivalis, Tannerella forsythensis, and Prevotella intermedia. The bacterium P gingivalis can actually start the clotting process, which is the first step in a heart attack and a stroke.13,15 Even the simple act of chewing constantly introduces these pathogens into the bloodstream in patients with severe periodontitis.1,6,9,13-17 Patients at high risk for development of infective endocarditis are advised to maintain scrupulous oral hygiene to prevent bacteremias.11

Multiple studies have found that even when other risk factors, such as smoking, genetics, high stress levels, and lower levels of education, are ruled out, periodontal diseases are associated with a narrowing of the coronary arteries in males, although no increase in risk has been found in females.7 The first National Health and Nutrition Examination Survey (NHANES I) reported that patients with periodontal diseases have a 25% increased risk for CVD compared with patients who have periodontal health.7 Genco's review of the Pima Indian studies determined that persons over 60 years of age who had periodontal bone loss are almost 3 times more likely to develop CVD than those without bone loss, even adjusting for other factors such as diabetes.4 Other university studies have found that the severity of the periodontal destruction is positively correlated to the severity of CVD and the development of atherosclerotic plaques.7

The news is not all bad however. A study tested patients with CVD and high levels of CRP who flossed their teeth at least every other day. Six months after these patients were given periodontal therapy, their CRP levels dropped to a normal range. When they stopped flossing, their CRP levels became elevated within 6 months.18 Similar studies looked at the effect of intensive periodontal therapy on the blood vessel walls. Within 6 months, the blood flow through the arteries improved in patients who received periodontal therapy.19 At least 3 major studies have shown that periodontal therapy is associated with improvement of systemic inflammation and with reduction of markers for CVD.8 Dental assistants can use this information to help their patients by educating them on the relationship between inflammation in the mouth and increased risk for heart disease. If dental assistants can further help patients improve their home care and reduce the severity of inflammation, they can positively affect their patients' overall health.
And Baby Makes 3

For many years, "pregnancy gingivitis" was simply considered an annoyance, but the evidence is mounting that severe, chronic gingivitis and periodontitis may be a risk factor of preterm and low-birth-weight babies, and is linked with other negative pregnancy outcomes.1,6,7,9,11,13,15,16,20-25 Uterine contractions and labor are normally induced by the body's production of oxytocin, which is produced by the hypothalamus and prostaglandins in the uterus during the later part of the third trimester of pregnancy. Prostaglandins also are produced in response to inflammation, and it is theorized that the chronic inflammation of gingivitis and periodontitis during pregnancy can cause preterm labor.15 Numerous studies have demonstrated that periodontal diseases preceded complications during pregnancy. Preterm and low-birth-weight babies are less likely to survive than full-term infants and are at greater risk for developmental, respiratory, and other types of health problems.7

Other researchers have isolated periodontal pathogens in the placenta and amniotic fluid and hypothesize that the fetal exposure to the maternal oral bacteria triggers the production of antibodies that cause tissue destruction, trigger preterm labor, and may impair development of the fetus.8 Preeclampsia is severe hypertension after the 20th week of pregnancy that affects 6% to 8% of all pregnant women and is responsible for 15% of fetal deaths and severe complications for the baby. Researchers have recently found evidence of placental contamination by periodontal pathogens in women who required emergency cesarean sections because of preeclampsia. Many animal studies have demonstrated the adverse effect of bacterial infections including abnormal placentas, altered brain development, and problems with labor and delivery, but this was the first human study to link preeclampsia to oral pathogens.26 Dental assistants can provide this information to their patients to improve the outcomes of labor and delivery by stressing the importance of optimal self-care and frequent dental visits during pregnancy.
Every Breath You Take

The oral cavity and the respiratory tree share common airspaces, and chronic obstructive pulmonary disease (COPD) and pneumonia have been associated with poor oral health.15,26 The lungs and lower respiratory spaces are normally sterile, but oral biofilm can serve as a reservoir for hospital-acquired respiratory bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and bacteria from the gastrointestinal tract. These bacteria may be released into saliva and aspirated into the lungs, causing infections such as aspiration pneumonia. According to one study, aspiration of material from the upper airway into the lungs occurs in 45% of healthy persons, compared with 70% of those with impaired consciousness.7 Intubation is another mechanism for introducing foreign bacteria into the lower airspace.15 Among health careÒacquired (nosocomial) infections, ventilator-associated pneumonia is the leading cause of death. Bacteria associated with this type of pneumonia are common in the dental plaque of intensive care patients, and rare in those outside the hospital setting. An even stronger association occurs when there is antibiotic exposure, probably because the antibiotics decrease the normal (healthy) bacteria that inhabit the mouth and compete with the other, more pathogenic microorganisms that then take over.27 Simple experiments using oral antimicrobial rinses and improved oral hygiene decreased the incidence of nosocomial pneumonia by 24% to 60% compared with controls.26,28 Patients with COPD are extremely vulnerable to respiratory infections and pneumonia, so eliminating sources of infection by immaculate home and professional oral care is critical for this group. Any patient with this disease who presents with difficulty breathing, constant productive cough, and flulike symptoms should immediately be referred to a physician.13
Cancer and Periodontal Diseases

Chronic inflammation is known to be a risk factor in many types of human cancers. As early as the 19th century, Virchow linked tumor formation with chronic irritation.29 Chronic irritation and the chemical and cellular reactions associated with bacterial and viral illness are implicated in the connection between: (1) Helicobacter pylori and adenocarcinoma of the stomach; (2) Epstein-Barr virus and non-Hodgkin's lymphoma, Hodgkin's lymphoma and nasopharyngeal cancer and other lymphomas; (3) hepatitis B or C and hepatocellular carcinoma; (4) human herpes virus and Kaposi sarcoma; and (5) the human papilloma virus and oral and cervical cancers.28 There is also an increase of some malignancies in immunosuppressed patients, such as the increase in lymphomas and sarcomas in HIV-positive persons.11,22,29 The theory is that the continued insult of the inflammatory cells and their destructive cytokines may trigger malignant tumor formation in patients with a genetic predisposition to certain types of cancer.27,29

Lichen planus is an example of a chronic inflammatory disease affecting oral mucous membranes and the skin. The oral form is present in 1% to 2% of adults, and is considered by the World Health Organization to be a premalignant condition with a low, but clinically relevant transformation to oral squamous cell carcinoma (OSCC).29 Periodontal diseases have been associated with an elevated risk of OSCC of the tongue, even when smoking and other risk factors are excluded.29,30 While the relationship between oral inflammation and oral cancers seems fairly straightforward, a recent study found that men with moderate and severe periodontal diseases and tooth loss had a 64% greater risk of pancreatic cancer compared with men with good oral health.27 The researchers hypothesized that the systemic inflammation triggered by periodontal diseases, along with the high levels of nitrate-producing (nitrates being known carcinogens) bacteria in the mouths of persons with periodontal diseases may interact with gastric acids to trigger the development of pancreatic cancer. The researchers also found that the more severe the periodontal diseases, and the greater the tooth loss, the greater the risk of malignancy. The levels of CRPs were 30% higher in the group with periodontal diseases compared with the healthy group, demonstrating higher levels of systemic inflammation.29
Summary

Evidence-based research is mounting that the health of the oral cavity can drastically influence the total health of the individual. Periodontal diseases are infections of the supporting structures of the teeth, but the chronic inflammation of the diseases triggers the body's immune system to cause damage to many different body systems, such as the cardiovascular system, the respiratory system, and a developing fetus, and can increase the severity of existing diseases, such as diabetes. Dental assistants play an important role in patient education and assessment. By understanding the associations between oral and systemic conditions they can not only help prevent periodontal diseases, but also improve the overall health of their patients by encouraging referrals for patients with these conditions. As the body of evidence linking oral and systemic health grows, the importance of the dental assistant as patient advocate also will grow.
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