August 1, 2013
by Dr. Blake Nicolucci
Prophylactic antibiotic coverage has been a very controversial topic in the profession over the years. There seems to be little ‘scientific data’ to support the current protocols for antibiotic coverage — as it pertains to premedication for heart surgeries and valve replacements as well as implanted joints and prosthetic devices. We do have a so called ‘Protocol’ for dentistry which we use as a guide, but again is there scientific backing for the ‘Protocol’, and is it more of a — “It sounds reasonable to do something” — protocol?
We are entering an era of the ‘superbug’, and I believe this is a result of over prescribing antibiotics on a regular basis for the ‘Just in Case’ reasoning. We are advised (by our governing body the Canadian Dental Association) to use appropriate antibiotics to help prevent colateral medical problems in patients with certain heart conditions and with new joint replacements. Our present prophylactic antibiotic regiment is: two grams of Amoxicillin orally, one hour prior to the procedure.
Unfortunately, most dentists (in an effort to stay within the guidelines and reduce the risk of litigation and charges of malpractice) will routinely prescribe antibiotics. But it is the results of the research done by the American Heart Association panel that should provide us with some guidance. The panel concluded that, “Only an extremely small number of cases of infective endocarditis might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100% effective.”
G.J. Roberts (in the Pediatric Journal of Cardiology) states, “Dentists are innocent! Everyday bacteremia is the real culprit.” Roberts estimated that brushing your teeth twice a day for a year had 154,000 times greater risk of acquiring some type of bacteremia than having an extraction and that any type of dento-gingival manipulation causes ‘bacteremia’. Statements like this are the reason we seem to be medicating indiscriminately. There is a general belief that bacterial endocarditis is the result of dental treatment (even though the level and potency of the bacteremia is still highly questionable). The estimated duration of bacteremia from dental procedures has been shown to be between 10 minutes and three hours. Obviously, the need to medicate or not to would be easier for us to assess if we knew ahead of time what the duration of the bacteremia was going to be.
None of the samples in any of the studies used had indicated they had taken a pre-surgical blood sample to get a baseline bacteremia before post-surgical levels were attained. The researchers assumed that all of the patients being tested had a zero level of odontogenic bacteria before the surgery was performed. This is unfortunate, since on further examination of a new study sample of pre-operative patients, 86 percent of patients had some level of bacteremia before procedures were initiated. It seems only reasonable to me that comparative blood samples be taken both before surgery and then again after surgery to measure a ‘true’ qualitative and quantitative level of bacteremia following any given dental procedure. This study can be accessed at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1861185/.
In a more recent article by Dr. W. Gifford-Jones (03/22/2013), he wrote about a report from the Cleveland Clinic which states, “We believe the available evidence does not support routine antibiotic prophylaxis before dental procedures in patients who have undergone total joint replacement, even though the practice is very common and even though professional societies recommend it in patients at high risk or even in all patients.” According to scientific data, ‘Staphylococcus aureus’ is the bacteria that produce most of the post-operative joint infections, but researchers at the Clinic go on to say that it is very rare to see this bacteria in either the oral cavity or in the bloodstream following dental procedures. It has been established that the viridans-group streptococci bacteria are the primary inhabitants of the mouth and they only account for a mere two percent of post-operative joint infections.
Another study by the Cleveland Clinic examined 1,000 patients who underwent some type of total joint replacement. Of these 1,000 patients, 226 underwent dental procedures but were not pre-medicated with antibiotics. At a six-year follow-up, it was discovered that not one patient had developed a prosthetic joint infection.
Gifford-Jones goes on to ask the question, “Who is right?” and of course, as you have already guessed, there is no single right answer. There are situations in which it would be prudent to use antibiotic coverage prophylactically (such as patients who have had previous joint infections, Type 1 diabetes, HIV and other immuno-suppressed diseases), but should patients be premedicated on such a broad or general basis? Does anyone consider the risk of patients developing ulcerative colitis — or a new generation of super-bug?
Apparently, 90 percent of the dental offices Dr. Gifford-Jones telephoned indicated that if a patient has had total joint replacement, premedication was mandatory before a dental hygiene appointment. He went on to state that this was like “using an elephant gun to kill a mouse!” This was a great article, and I encourage you to read it in its entirety!
I’d like to finish up with some studies from the National Institute of Health and Clinical Excellence (NICE) in Great Britain. They accumulated data from numerous countries world-wide to provide ‘data rich’ conclusions and acquire a broader sample base. A précis of their results indicated that:
• Since all previous study samples were very small, making conclusions about the ‘risk’ of developing infective endocarditis was not really possible.
• Infective endocarditis is so rare that it would be difficult to decide which procedures could increase the risk on patients with a pre-existing cardiac condition.
In short, I believe there is enough scientific evidence to rule out the complacent and general use of prophylactic antibiotics. These articles certainly provided me with some ‘food for thought’!
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