Reconnecting Practicing Hygienists with the Nation's Leading Educators and Researchers.

Perio Medicine

Robert J. Genco, DDS, PhD, talks to Dimensions about the oral/systemic link and what it means for the practice of dentistry and medicine.

Q. What does the term “periodontal medicine” mean and where did the term originate?

A. Periodontal medicine refers to those aspects of systemic disease that interact with periodontal diseases. It’s also defined as the management of periodontal diseases to modify the links between systemic and periodontal diseases. I’m sure there are several sources but the book Periodontal Medicine (published in 2000 by BC Decker Inc), written by myself and Louis F. Rose, DDS, MD; D. Walter Cohen DDS; and Brian L. Mealey, DDS, MS, introduced the term. We thought that writing a book would be a good way to broach the subject.


Q. What is the current focus of research regarding the periodontal diseases/systemic health link?

A. Right now, researchers are gathering more information related to causation and the practical application of the links. Much of the research is directed to randomized, controlled trials (RCTs) where periodontal interventions are carried out in subjects who have both periodontal diseases as well as one of the related systemic diseases like diabetes.

In the case of low birth weight, studies are looking at the effect of periodontal treatment on pregnant women who are at risk for low term birth weight. With cardiovascular disease, studies are looking at the effect of periodontal therapy in preventing secondary coronary events. Several RCTs are also going on in the area of respiratory infection.

RCTs are the major focus of new research and they accomplish several goals. First, they may provide information about causality. If in fact treating periodontal diseases reduces glycemic control, for example, there’s probably a cause or link between periodontal diseases and poor glycemic control. The other goal RCTs accomplish is to provide the basis for public health or practice recommendations. In the future, we may make recommendations that if periodontal diseases are prevented or treated, the systemic diseases with which they are associated will be positively affected based on the results of well-done and replicated RCTs.

Q. How far away is the dental profession from making practice recommendations?

A. In the area of respiratory disease, many hospitals are instituting oral hygiene measures in intensive care units for patients on ventilators. A major Catholic health care system is using this as part of its standard operating procedure in the intensive care units for intubated patients with remarkable reduction in respiratory infections. Hence, there is already some application of the oral systemic knowledge in the respiratory infection area.

In diabetes, several studies show that if you treat periodontal diseases in people with diabetes, their glycated hemoglobin gets better.1 However, these are not universal studies. Many have been fairly small with 50-100 subjects in a group. Larger studies are needed that look at 300 to 400 patients. In order to make practice recommendations, several of these larger studies are needed. They are currently under design.

Q. How are the studies being funded?

A. The National Institute of Dental and Craniofacial Research has a very active clinical research program with a series of grants for clinical trials. They have planning grants to actually write the protocols and the standard operating manuals, and then eventually, they will fund the phase three trials, which are the definitive trials.

In the area of heart disease, a large pilot trial has already been done and an application was submitted to do a definitive trial but it was not funded. However, there is hope that it will be revised and then funded. The study on cardiovascular disease will take 6 to 7 years and it will look at preventing secondary heart disease in patients who have already had a myocardial infarction and survived. The current rate of recurrence is about 6% per year, which is fairly low. To see even a 20% reduction would take very large study numbers, for example 3,000 in each group.

Some of the low birth weight studies that looked at the effect of periodontal treatment on low birth weight were funded by the National Institutes of Health (NIH) and another was funded by the state of Pennsylvania. One of the NIH-supported studies was recently published in the New England Journal of Medicine and was negative.2 Most epidemiologic studies show that the early events are probably most affected by periodontal diseases—still birth and very low weight births. Hence, it may be that an RCT on the effects of periodontal diseases on these early events may be necessary.

Much of the current research is also on mechanisms. Researchers are delving into the nature of the link between periodontal pathogenic bacteria and pathophysiologic functions in systemic diseases. Also, animal models have been developed to look at the effects of periodontal infection on cardiovascular disease. There’s an animal model of type 2 diabetes that has been studied where periodontal infection is superimposed on diabetes in these models and severe periodontal diseases result.


Q. What about the recent research that suggests a relationship between periodontal diseases and oral pharyngeal cancer?

A. This was a case controlled study carried out here at the University of Buffalo by Mine Tezal, DDS, PhD, and Maureen Sullivan, DDS, at the Roswell Park Cancer Institute.3 It’s an intriguing hypothesis, but there are so many major risk factors for oral cancer, including alcohol and smoking, to see an additional effect of periodontal diseases is very difficult. Caution needs to be exerted in interpreting these very preliminary results, and they need to be replicated in other populations with careful adjustment for potential confounding factors, such as smoking.

Q. Is there a study showing a correlation between pancreatic cancer and periodontitis?

A. Yes, but again, it’s one study so caution needs to be exercised. This was a large study done at Harvard University. One of the concerns with this particular study is that the periodontal disease was self-reported, meaning that the margin of error could be high. Again, this would have to be replicated in other populations and, if repeatable, mechanisms studies and RCTs would have to be carried out to better understand the proposed relationship.


Q. What are some of the other specific perio/systemic concerns that women experience throughout their lifetime?

A. One is the well-known phenomenon of pregnancy gingivitis. A similar form of gingivitis also affects women around menopause and those who have conditions affecting the ovaries, like polycystic ovaries. The gingivitis usually subsides once the hormonal condition is resolved. The use of lower dose birth control pills with less progesterone has resulted in lower levels of gingivitis associated with the use of birth control pills.

The other issue is the association of periodontal diseases and low birth weight, which is suggested by epidemiologic studies. The Michalowicz study2 did show that there is probably no danger in the scaling and root planing of pregnant women, although this study failed to demonstrate a protective effect of periodontitis treatment in reducing adverse pregnancy outcomes.

Another link is the relationship between osteoporosis and periodontal diseases. This is not just a women’s issue, although it has been studied mostly in women. It probably is a similar issue in men, as men suffer from osteoporosis maybe a decade later. Jean Wactawksi-Wende, PhD, at the University of Buffalo has shown in some fairly large and convincing studies that there is a greater risk for periodontal diseases in women who are osteoporotic or even osteopenic.4 A related study of dietary intake of calcium showed that if women have low calcium in their diet, they’re more prone to periodontal diseases.5 Men experienced a similar result but the effect was greater in women. In this study, the level of calcium intake in the diet was quite low in general. One third of the subjects had less than half the recommended intake of calcium. There is an overall low level of dietary calcium intake in the United States population, which could be a significant issue in terms of periodontal diseases. This really exemplifies that dental professionals should be involved in at least pointing this relationship out to our women patients. We can advise them that it’s important to have enough calcium in the diet and to prevent osteoporosis because it can have dental implications.

Q. Is there research that supports a relationship between stress and periodontal problems?

A .Research does exist. A study was done here in Buffalo and Erie County, NY. It was published in the mid-1990s. It was a difficult study to accomplish but we had a talented behavioral scientist working with us—Lisa Tedesco, PhD.6 We didn’t just look at stress but also at distress and coping. We found some very interesting relationships between stress, mainly the chronic types of financial stress, and more severe periodontal diseases. The rates of disease were higher especially in those who didn’t cope well. If the study participants coped well, even if they had stressful financial problems, they didn’t have more periodontal diseases. A Japanese group recently published a study in the European Journal of Medicine.7 They found that stress is related to self-help and working and that these were factors in increasing the severity of periodontal diseases. This study was done on 1,000 participants in Japan. Our study was done on 1,400 adults in Erie County, NY. So, the results were similar even in two different populations. There have been many small studies—case controls of psychiatric patients, patient caregivers for example—and in many of these studies, periodontal diseases are more severe in the more stressed individuals.

Q. Are there other periodontal systemic links that are being explored?

A. We’re looking at people with diabetes who have periodontal diseases. We’ve been studying the Pima Indians for more than 25 years. They have an extremely high incidence of type 2 diabetes (40%) and very high levels of periodontitis. We took about 800 people with diabetes at baseline, some with and some without periodontal diseases, and followed them for a median time of 13 years. Those with diabetes who had periodontal diseases had a two times greater risk of dying of heart disease, as well as a four times greater risk of dying from kidney disease.8 These later results were unexpected. More recently we looked at albuminuria, which is indicative of kidney damage. We found a relationship with periodontal diseases.9 Those individuals who have diabetes and periodontal diseases have a five fold greater chance of having albuminuria than those with diabetes who don’t have periodontal diseases. This renal connection is quite interesting, and it may be that it follows the same basic pathophysiologic process as in heart disease, ie, the periodontal infection causes inflammation, and the inflammation spills over into the bloodstream, causing vascular damage. If the blood vessels are in the heart, it leads to cardiovascular disease and if the blood vessels in the kidney are affected, kidney disease results.

As a profession, dentistry has moved away from medicine, but now with periodontal medicine, we should be getting closer over the next decade or so.

Q. Are health care professionals knowledgeable about this?
A. Often even if health care professionals understand the link between oral and systemic health, they don’t know what to do about it. So, we have developed a self-report questionnaire, which can be used by medical health care workers who specialize in treating diabetic, cardiovascular, or obstetric patients, that gives them the tools to ask their patients questions about oral health. If the patient answers positively for being at risk for periodontal diseases, he or she would be referred to a dental professional. The problem is that periodontal diseases are difficult to detect just by looking in the mouth so the referring health care professionals may get it wrong and send 100 patients to the dentist when only 10 have periodontal diseases. The yield has to be greater, like 60 or 70 patients out of 100, then some false positives will be accepted.

Q. What is the role of the dental hygienist?

A. Dental hygienists are at the forefront of prevention. They are updating medical histories, they’re talking to patients, and patients are asking them questions. It’s so important for dental hygienists to have up-to-date, accurate information because they are often the ones educating the patients.

The dental hygienist needs to be knowledgeable about all of these risk factors. The oral systemic link cannot be ignored any longer, we have to act on this new knowledge about the relationship between periodontal diseases and systemic diseases. We must be active in promoting smoking cessation for our patients, the same for diet. I’m a firm believer that dental professionals should be involved in diet. We’re already involved for caries and sugar, why not calcium? Why not for general nutrition, and to reduce body mass index? This could be a major role for the dental hygienist to be actively involved in the identification of risk factors and their management in the dental office.


  1. Grossi SG, Skrepcinski FB, DeCaro T, et al. Treatment of periodontal disease in diabetics reduces glycated hemoglobin. J Periodontol. 1997;68:713-719.
  2. Michalowicz BS, Hodges JS, DiAngelis AJ, et al. Treatment of periodontal disease and the risk of preterm birth. N Engl J Med. 2006;355:1885-1894.
  3. Tezal M, Sullivan MA, Reid ME, et al. Chronic periodontitis and the risk of tongue cancer. Arch Otolaryngol Head Neck Surg. 2007;133:450-454.
  4. Wactawski-Wende J, Hausmann E, Hovey K, Trevisan M, Grossi S, Genco RJ. The association between osteoporosis and alveolar crestal height in postmenopausal women. J Periodontol. 2005;76:(11Suppl):2116-2124.
  5. Nishida M, Grossi SG, Dunford RG, Ho AW, Trevisan M, Genco RJ. Calcium and the risk for periodontal disease. J Periodontol. 2000;71:1057-1066.
  6. Genco RJ, Ho AW, Kopman J, Grossi SG, Dunford RG, Tedesco LA. Models to evaluate the role of stress in periodontal disease. Ann Periodontol. 1998;3:288-302.
  7. Akhter R, Hannan MA, Okhubo R, Morita M. Relationship between stress factor and periodontal disease in a rural area population in Japan. Eur J Med Res. 2005;10:352-357.
  8. Saremi A, Nelson RG, Tulloch-Reid M, et al. Periodontal disease and mortality in type 2 diabetes. Diabetes Care. 2005;28:27-32.
  9. Shultis WA, Weil EJ, Looker HC, et al. Effect of periodontitis on overt nephropathy and end-stage renal disease in type 2 diabetes. Diabetes Care. 2007;30:306-311.

From Dimensions of Dental Hygiene. March 2008;6(3): 16-18.

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