Written by David S. Ostreicher, DDS, MS, MPH Friday, 14 September 2012 11:40
Yes, you read the title correctly. As important as seat belts are as a preventive measure, toothbrushes have a far greater impact on the health and longevity of the American public. According to the National Highway Traffic Safety Administration (NHTSA), seat belts save about 13,000 lives a year, nationwide. That is no small number: more than 1,000 Americans each month owe their lives to the 5 seconds it took them to “buckle up.” NHTSA points out that seatbelts reduce a person’s chances of dying in a crash by 45% and being injured by 50%. However, seat belts probably will not play a role in saving your life, because chances are you will not be in a serious car crash; most Americans never are.
On the other hand, most Americans have gum disease. Estimates are that up to 80% of American adults suffer either from gingivitis or periodontal disease.1 You have probably told your patients that the most common cause of tooth loss among adults is periodontal disease. What you probably haven’t told them is that tooth loss is one of the least important consequences of periodontal disease. Periodontal disease is a significant risk factor for heart attack, stroke, low-birthweight infants, and some forms of cancer. While very few of your patients will die from a car crash, many of them will die from a heart attack or cancer. And, believe it or not, using a toothbrush and eliminating periodontal disease reduces the chances of dying from either of these causes.
The Oral Systemic Connection
The premise that oral health may influence systemic health is not new but it has undergone a number of modifications throughout the years. In 400 BC, Hippocrates reported that a patient was cured of arthritis after the extraction of an ill tooth. More recently, the theory that poor dental health can cause several systemic diseases has been called the Theory of Focal Infection. Focal infection can be traced back to the late 19th century when Dr. Willoughby Miller, an oral microbiologist, claimed that cavities played a role in the etiology of gastric problems, lung and brain abscesses, and other medical conditions.
In 1900, Dr. William Hunter, a prominent British physician, drew wide attention to these theories by presenting them in a lecture to the medical students of McGill University in Canada.
Dr. Frank Billings formally introduced the focal infection theory to American physicians. His lectures at Stanford University Medical School were published in 1916 in the book, Focal Infections. Dr. Billings went a step further than Dr. Hunter and promoted tonsillectomies and dental extractions as remedies for focal infections. Even prominent doctors like Dr. Charles Mayo (founder of the prestigious Mayo Clinic) promoted focal infection.
In 1923, Dr. Weston Price, chairman of the Research Section of the ADA, published Dental Infections, Oral and Systemic. Despite Dr. Price himself saying that more research was needed and care should be used in applying focal infection theory, Dental Infections, Oral and Systemic was used as a reference in textbooks and diagnosis guides of the early to mid 1930s.
The focal theory began to lose steam as scientists and physicians began to embrace modern “evidence-based” theories of disease. Perhaps a turning point in the popularity of focal infection was offered in an article published in the Annals of Internal Medicine in 1938. A former proponent of the theory, Dr. Russell Cecil stated that “focal infection is a splendid example of a plausible medical theory which is in danger of being converted by its enthusiastic supporters into the status of an accepted fact.” His study of 200 cases of rheumatoid arthritis documented no curative benefit of tonsillectomies or dental extractions. The final demise of the focal theory can probably be traced to a 1940 paper published in the Journal of the American Medical Association entitled, “Focal Infection and Systemic Disease: A Critical Appraisal,” by Drs. Hobart Reimann and Paul Havens. The authors showed that the theory was completely unproven.
A special 1951 issue of the Journal of the American Dental Association stated: “Many authorities, who formally felt that focal infection was an important etiologic factor in systemic disease, have become skeptical and now recommend less radical procedures in the treatment of such disorder.”
Toward the end of the 20th century, researchers began to view gingivitis and periodontal disease as an infection and chronic inflammatory condition. Like other chronic inflammatory diseases, the results can become widespread. The bacteria and their toxins can enter the bloodstream and reach distant sites, causing havoc and disease in organs throughout the body.
Beginning in the 1980s, a series of journal articles describing the association between periodontal disease and coronary heart disease (CHD), stroke and preterm birth/low-birthweight caught the attention of the medical and dental professions. While in some sense this can be construed as a return to the theory of focal infection, the response from the dental and medical professions has been more conservative. Modern investigative science uses greater sophistication in assaying data. There is a better understanding of the limits of epidemiologic studies in establishing causality and greater appreciation of the etiology of periodontal diseases and associated systemic diseases. In short, we have come to understand that the major killer diseases—cardiovascular disease (CVD) and cancer—have multiple causes and multiple risk factors.
There is no single cause for heart attacks. It is not smoking, not high blood pressure, not obesity, not high cholesterol, not stress, not lack of exercise, not genetics; and no, it is not periodontal disease. Rather it is a combination of these, and other risk factors that add layer upon layer of increased risk of suffering a heart attack. Modern science has come to understand that many chronic diseases such as CVD and cancer are multifactorial in nature, and anything that we can do to eliminate risk factors can go a long way to lengthening our lives.
In the past 2 decades there have been hundreds of studies published in the peer-reviewed medical journals that show periodontal disease is a risk factor for heart attacks. Several thousand more have been published in dental journals. Upon further investigation, it appears clear that brushing your teeth and avoiding periodontal disease really can save your life.
The modern connection between periodontal disease and CVD lies in the chronic, inflammatory nature of gum disease. Periodontal disease, simply put, is a bacterial infection of the gums and structures supporting the teeth. As with most infections throughout the entire body, gum infection leads to inflammation.
|A Twice Daily Lifesaving Act|
Jo-Anne Jones, RDH
The number of adults in the United States suffering from periodontal disease may be significantly higher than previous research has indicated, according to a study conducted by the US Centers for Disease Control and Prevention and the American Academy of Periodontology. This new information was published online in the Journal of Dental Research in September of 2010.
The same conundrum exists in today’s pharmacy as our dental patients wander aimlessly, like deer in headlights, looking at the multitude of oral hygiene aids. There are the latest gadgets as well as the scientifically studied offerings. It is our responsibility as dental professionals to choose products that are based on science, our clinical experiences, and align with the lifestyle, behaviors, manual dexterity, and financial comfort of our dental patients. In other words, exercise the evidence-based decision-making model.
Mechanisms of Action
There are several ways in which a bacterial infection, such as periodontal disease, can increase the risk of heart disease. Bacteria originating in mouth may enter the blood stream through ulcerations in the gums caused by periodontal disease. These bacteria can directly infect the blood vessel walls of the heart. Such infection may be largely asymptomatic, but can cause local vascular inflammation and injury, which would contribute to the development of lipid-rich plaques and atherosclerosis. Bacteria may also interact with blood cells or platelets, both of which integrate into the developing atherosclerotic plaque.
Bacterial products in the blood may also stimulate liver production of proinflammatory and procoagulant molecules such as C-reactive protein and fibrinogen, both of which are directly linked to heart attacks. Microbes may also stimulate various tissue factors, which can activate blood coagulation. During the process of coagulation, platelets become trapped in the growing clot (or thrombus). Thrombus formation is one of the key factors in the development of atherosclerotic plaques. As atherosclerotic plaques enlarge, the lumen of the coronary blood vessels narrows and the blood supply to the heart muscle becomes reduced. A heart attack, or myocardial infarction, results when a larger part of the coronary artery lumen becomes occluded. Failing to receive enough blood, the heart muscle dies.
In 2000 the US Department of Health and Human Services released Oral Health in America: A Report of the Surgeon General. This 300-page treatise reviewed, among other things, the relationship of periodontal disease and CVD. While the conclusions stopped short of categorically stating that brushing your teeth and eliminating periodontal disease will stop you from getting a heart attack, a clear connection was described. In the end, the authors2 concluded: “consistent findings of increased odds ratios and significant probability (P) values pointing to an association of periodontal and other oral infections with an increased risk for CVD.”
Since that report, scores of articles published in the medical journals suggest that brushing your teeth and reducing periodontal disease will indeed reduce your chances of suffering not only CVD and heart attacks, but some forms of cancers as well. An article in Archives of Internal Medicine3 concluded, “periodontal disease is an important risk factor for cerebrovascular accidents (strokes).”
Four years later, writing in the journal Critical Reviews in Oral Biology Medicine,4 the authors stated, “Overall, it appears that periodontal disease may indeed contribute to the pathogenesis of CVD.” A 2007 article appearing in Arteriosclerosis, Thrombosis and Vascular Biology concluded, “Our results suggest that the exposure to periodontal pathogens or endotoxin [toxins released by bacteria] induces systemic inflammation leading to increased risk for CVD.”5 When 5 researchers aiding the United States Preventive Services Task Force examined quality studies on the subject, they6 wrote, “Periodontal disease is a risk factor for CHD that is independent of traditional CHD risk factors, including socioeconomic status.” To test this theory, researchers performed periodontal treatment on a group of patients who had periodontal disease. They drew blood before treatment and one year after treatment. Markers for heart attack risk such as high-density lipoprotein (good cholesterol) and low-density lipoprotein (bad cholesterol) were studied. Those patients who received the periodontal therapy saw a significant improvement in their blood cholesterol and other markers. The authors7 concluded that “this study indicates that standard treatment for periodontal disease induces systemic changes in several biochemical markers that reflect the risk for atherosclerosis.”
Just as high cholesterol is a biomarker for CVD, so is high blood pressure. In a 2010 study, researchers measured periodontal bacteria levels in 653 subjects. They found a direct correlation between the amount of periodontal bacteria present and blood pressure. The more periodontal bacteria, the higher the patient’s blood pressure.8 Another 2010 study, this time published in the British Medical Journal, followed 11,869 men and women for 8 years. The authors found that those subjects who rarely brushed their teeth were nearly twice as likely to suffer a heart attack.9 This observation was confirmed in another 2010 study reported in Annals of Cardiac Anaesthesia. The researchers found that people with periodontal disease are almost twice as likely to suffer from coronary artery disease as those without periodontal disease.10
MEDICAL ESTABLISHMENT REVIEWS THE FACTS
The American Journal of Cardiology published an editor’s consensus on periodontitis and CVD in July, 2009. After a careful review of the literature, the editors reported that periodontal disease is a risk factor for heart attack, with a relative risk of 1.24 to 1.35. Basically translated, that means that if you have periodontal disease, you are 24% to 35% more likely to have a heart attack. More recently, in 2011, a paper entitled, “Periodontitis and CVD: Floss and reduce a potential risk factor for CVD,” was published in the journal, Angiology. The dramatic conclusion of the authors11 in this study suggests that periodontitis is a potential modifiable risk factor for CVD.
A careful review of the hundreds of studies and papers on the subject clearly leads to the conclusion that periodontal disease does not cause CVD, but rather is a contributing factor (or risk factor) toward heart disease. This leads one to speculate as to how much of a risk factor it is. Smoking, obesity, and high blood pressure are stronger risk factors, estimated at relative risk of 2.0 to 4.5. If smoking has a relative risk, for example, of 4.0, then loosely translated, you are 4 times more likely to suffer a heart attack if you are a smoker than if you are a nonsmoker. Does smoking cause heart attacks? No. Does smoking contribute to heart attacks? Absolutely! The same is true with periodontal disease.
Most research points to periodontal disease having a small, but significant, relative risk. Even if we take the lower number, such as relative risk = 1.24 as suggested by the American Journal of Cardiology study, the results of such a risk can be staggering because the number of people at risk is so high. Estimates are that as much as 80% of American adults suffer from some form of periodontal disease. Based upon these figures, 176 million Americans have a periodontal infection with inflamed gum tissue. Americans as a group suffer about one million heart attacks annually. If you are among the 176 million Americans who have periodontal disease, you are slightly more likely to suffer a heart attack than those who do not have a gum infection. Specifically, you are 1.2 times as likely. If one does the math (which is too complicated to demonstrate here), a relative risk of 1.2 translates to additional 158,000 heart attacks annually!
What does that mean? It means that if we could totally wipe out periodontal disease, we would eliminate about 158,000 heart attacks each year, nearly half of which are fatal. Of course, fully eradicating periodontal disease is unlikely in the near future. However, if we could reduce the prevalence of periodontal disease by, say half, we could eliminate 79,000 heart attacks. What if we could only reduce periodontal disease merely by 20%? Then we would eliminate nearly 32,000 heart attacks and save about 16,000 lives annually—more than seat belts do! Add to that the thousands of lives that would be saved by reducing some cancers, controlling diabetes, and premature birth, and the conclusion is clear. From a public health point of view, toothbrushes save more lives than seat belts!
Remember, 50 years ago automobile manufacturers and some citizens’ groups fought seat belts. They claimed buckling up was expensive, unproven, and unnecessary, claiming that seat belts interfered with driving, infringed upon one’s freedoms, and would trap passengers in their cars in the event of a fire or submersion. Even today, many states do not mandate seat belt use in school buses.
Similarly, while the evidence linking periodontal disease to heart attacks and strokes seems overwhelming, there are those who claim that cause and effect has still not been proven. Yes, there are still some who remain skeptical. On the other hand, it is difficult to formulate an argument against good oral health. It helps us in avoiding painful cavities, saving teeth, and eliminating bad breath and, at no extra cost, it may even save your life.
- US Department of Health and Human Services, National Institutes of Health. Periodontal (Gum) Disease. Causes, Symptoms, and Treatments. Bethesda, MD: National Institute of Dental and Craniofacial Research, National Oral Health Information Clearinghouse; July 2011. nidcr.nih.gov/NR/rdonlyres/7B7D24C2-02E5-47C8-B076-27CB580FAF82/0/PeriodontalGum_Eng.pdf. Accessed March 21, 2012.
- US Department of Health and Human Services. Oral Health in America: A Report of the Surgeon General. Washington, DC: US Dept of Health and Human Services; 2000:120. surgeongeneral.gov/library/oralhealth/. Accessed March 21, 2012.
- Wu T, Trevisan M, Genco RJ, et al. Periodontal disease and risk of cerebrovascular disease: the first national health and nutrition examination survey and its follow-up study. Arch Intern Med. 2000;160:2749-2755.
- Meurman JH, Sanz M, Janket SJ. Oral health, atherosclerosis, and cardiovascular disease. Crit Rev Oral Biol Med. 2004;15:403-413.
- Pussinen PJ, Tuomisto K, Jousilahti P, et al. Endotoxemia, immune response to periodontal pathogens, and systemic inflammation associate with incident cardiovascular disease events. Arterioscler Thromb Vasc Biol. 2007;27:1433-1439.
- Humphrey LL, Fu R, Buckley DI, et al. Periodontal disease and coronary heart disease incidence: a systematic review and meta-analysis. J Gen Intern Med. 2008;23:2079-2086.
- Buhlin K, Hultin M, Norderyd O, et al. Periodontal treatment influences risk markers for atherosclerosis in patients with severe periodontitis. Atherosclerosis. 2009;206:518-522.
- Desvarieux M, Demmer RT, Jacobs DR Jr, et al. Periodontal bacteria and hypertension: the oral infections and vascular disease epidemiology study (INVEST). J Hypertens. 2010;28:1413-1421.
- de Oliveira C, Watt R, Hamer M. Toothbrushing, inflammation, and risk of cardiovascular disease: results from Scottish Health Survey. BMJ. 2010;340:c2451.
- Saini R, Saini S, Saini SR. Periodontal diseases: a risk factor to cardiovascular disease. Ann Card Anaesth. 2010;13:159-161.
- Friedewald VE, Kornman KS, Beck JD, et al; American Journal of Cardiology; Journal of Periodontology. The American Journal of Cardiology and Journal of Periodontology Editors’ Consensus: periodontitis and atherosclerotic cardiovascular disease. Am J Cardiol. 2009;104:59-68.
Disclosure: Dr. Ostreicher reports no disclosures.
Disclosure: Ms. Jones works in the capacity of a key opinion leader for Philips Oral Healthcare.