Dental updates from Dr. Mckeever.

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Prevention of Infective Endocarditis (IE); the New Rules!

For dental patients with cardiac abnormalities and for practicing dentists there is really good news. The American Heart Association guidelines for infective endocarditis prevention, after a fifty year evolution and nine revisions over that time period, has finally concluded that taking antibiotic premedication before dental visits (for "invasive" procedures such as cleanings, extractions, root canal fillings and gum surgery) is no longer necessary for most heart patients. (This is also true for patients undergoing gastro-intestinal and genito-urinary procedures). I would guess that dentists premedicate around 10% of all patients before their teeth are cleaned based upon the old standards and recommended by their physicians.

The new guidelines are based on a growing body of scientific evidence weighing the effectiveness of antibiotics against potential risks. The updated recommendations say that only people who are at the greatest risk of bad outcomes from IE, which is an infection of the heart's inner lining or heart valves, should receive short-term preventive antibiotics before these routine dental procedures. These high-risk cardiac conditions are:
*prosthetic cardiac valve
*previous infective endocarditis
*congenital heart disease (CHD) in patients with:
-unrepaired cyanotic CHD, including palliative shunts and conduits
-completely repaired congenital heart defect with prosthetic material, whether placed by
surgery or by catheter, but only for six months after the procedure
-repaired CHD with residual defects at or adjacent to the site of a prosthetic patch or
prosthetic device
*cardiac transplantation recipients who develop cardiac valvulopathy (valve problems)
The most common underlying condition that presidposes IE in the Western world is due to mitral valve prolapse (MVP). However, the absolute incidence of a subsequent episode of IE is extremely low for the entire population with MVP (either with or without a murmur) and even if that occurred, the resultant infecton is not usually associated with the grave outcomes that can occur in the patients with the above-mentioned risk factors! There is no evidence that coronary artery bypass graft surgery or arterial stents are associated with a long-term risk for infection; i.e. preventive antibiotics are not recommended for these patients.

Published data does not demonstate convincingly that the administration of antibiotics prior to invasive procedures prevents IE associated with germs that may have entered the bloodstream (bacteremia) during those invasive procedures. In fact, transient bacteremias occur frequently during routing daily activities unrelated to any medical or dental procedure. Tooth brushing and/or flossing, use of toothpicks, use of water irrigation devices and chewing food all have anywhere from a 5 to 68% risk of initiating these bacteremias (the variance probably due to how clean one's mouth is being kept). A 1999 study estimates that tooth brushing for a year carried a 154,000 times greater risk of exposure to blood-borne bacteria than a single tooth extraction. And, it is now a fact that people with chronic periodontal disease (pyorrhea) have a much higher incidence of cardiovascular disease due to the inflammation that is brought on inside of the vessels by bacterial stimulation from the every day activities as listed above. Dr. Walter Wilson, professor of medicine at the Mayo Clinic and chairman of the AHA group that wrote the new guidelines, states that, "Maintaining good oral health and hygiene appears to be more protective than preventive antibiotics. This changes the whole philosophy of how we have constructed these recommendations for the last fifty years. Rather than being based on the risk of getting IE, they're based on the risk of which patients would have the worst outcome from an infection".

One might ask what is wrong with taking antibiotics to provide the patient with a sense of security? Patients should be aware that overuse of antibiotics can lead to a worse outcome than if they were not used at all. (I have two patients in my practice that almost died from taking antibiotics) According to researchers at the University of Antwerp in Belgium, taking a single course of certain antibiotics increases the levels of antibiotic-resistant bacteria in the mouth and this effect can last up to six months. Thus, even after one short course of antibiotics (a preventive dose for dental procedures is just one dose prior to the appointment), a person could spread resistant strains of germs to family members, hospitals or dental clinics for months to come. Antibiotic resistant germs are increasing as the use of antibiotics in the population increases making it more difficult for them to have a desired effect on subsequent bacterial infections and, as a result, we are running out of ways to fight disease. Not having to pre-medicated dental patients will be a really big help in reducing this problem.

*If you have been given preventive antibiotics before dental appointments in the past and are not comfortable with our recommending these new guidelines, call your cardiologist for his take on the new guidelines. Also, the preventive antibiotics rules recommended by orthopedic surgeons after joint replacements are still in play; I feel like, eventually, these to will be dropped since there has never been a case of joint infection reported in the literature that was specifically related to a dental procedure..

posted by Steve at 5:42 PM