Systemic Antibiotic Use in Endodontics by Ron Hill, DDS, MSD

This was published in Journal of Greater Houston Dental Society, April 2018

Since the accidental discovery of penicillin by Fleming in 1928, antibiotics have been essential medications for treating localized and systemic bacterial infections. There are now over 100 different types of antibiotics available to clinicians, but it is estimated that 50% of all antibiotics are prescribed incorrectly or misused by patients. This has led to the emergence of multidrug resistant bacterial strains which are responsible for an estimated 23,000 deaths per year and many more life-threatening infections.

In dentistry, one of the more common uses for antibiotics is to treat infections of endodontic origin. A short review of endodontic infections and proper treatment guidelines, including when and how to prescribe systemic antibiotics will help the clinician avoid improper use of this important medication.

Although pulpal inflammation can be caused by bacteria gaining access to the pulpal tissues, the bacteria have yet to overwhelm the pulp and are not growing at a high enough rate that antibiotics are indicated. Multiple randomized clinical trials have clearly shown that antibiotics have no effect on reducing the symptoms of an irreversible pulpitis and are not indicated in these cases. The most effective treatment is an anti-inflammatory medication along with adequate pulpal debridement.

In cases of pulpal necrosis, the pulpal tissue becomes liquefied, and therefore is no longer vascularized. Orally administered drugs are not able to reach the site of the infection (the canal space), and are therefore ineffective. If there is an acute apical abscess, defined by pain and swelling in addition to a necrotic pulp, the presence of pus in the periapical tissues limits vascular supply. Proteins and cellular debris can bind and sequester the antibiotics, rendering them ineffective, and drainage of the affected area is indicated in addition to adequate pulpal debridement.

Evidence based studies have repeatedly shown that not only are antibiotics inadequate to treat endodontic symptoms in the absence of definitive pulpal treatment, they have also been shown that they are NOT needed in cases where adequate endodontic treatment has been completed. The symptoms will improve and pain management should be the chief aim of the prescribing clinician. Many of the studies that indicate prescribing antibiotics for patient comfort and apprehension or anecdotal in nature, and are not relevant using current evidence based standards. Any improvement a patient feels from prescribing an unnecessary antibiotic are due to a placebo effect, concurrent analgesic prescription, the completion of adequate endodontic treatment, or a combination of the three.

In cases of a spreading systemic infection (fever, malaise, lymphadenopathy cellulitis), immunocompromised patient or other compounding systemic illness, antibiotics can (and should) be used ONLY when accompanied by adequate treatment. For endodontic infections, obligate and facultative anaerobes dominate, and beta-lactam antibiotics are still the drug of choice. Amoxicillin has better bioavailability and a longer half-life than penicillin, allowing a more normal 8-hour dosing regimen which results in better patient compliance. The addition of clavulanic acid (Augmentin) or metronidazole 125mg has shown almost 100% effectiveness against endodontic pathogens when amoxicillin alone is ineffective. Although there is not much evidence available showing duration of treatment, between 2-5 days has been shown to be adequate for dental infections and a 7-day course is very seldom needed.

In 2017, the American Association of Endodontists reviewed and updated the guidelines on the use of systemic antibiotics based on the latest available evidence. For further information and review, I encourage you to read the full position statement.

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