Antibiotic Therapy

Systemic Antibiotic Therapy

Systemic antibiotics are drugs that, when given, affect the whole body. Normally they are administered in pill form when used in periodontal treatment. Periodontists use systemic antibiotics to treat acute infections, such as a gum abscess (gum boil), and also before treatment when patients have certain medical conditions, such as congenital heart defects and artificial heart valves or joints. (See Prophylactic Antibiotics). Systemic antibiotics are also recommended for two weeks after regeneration procedures and when implants are placed. This is done to make sure there is no infection during the early healing stages, which are critical with these surgical procedures.

Because periodontal disease is an infection, it would seem logical that antibiotics would eliminate the problem. Unfortunately, when treating routine periodontal breakdown, the effects of antibiotics are short-lived. This is because the bacteria that cause the disease reform immediately after the antibiotics are discontinued. In fact, periodontal cleanings done to remove calculus and plaque appear to be as effective as antibiotics in controlling the infection.

As a rule, for most routine periodontal conditions, systemic antibiotics are not necessary or even useful. In some advanced cases there may be very specific harmful bacteria that can be eradicated with systemic antibiotics. For these cases, a short-term treatment of antibiotics may be useful. In cases where traditional treatment does not produce the expected results, the mouth may be cultured to analyze which specific bacteria are present. This will guide the therapist on which antibiotic to use.

Because overuse of systemic antibiotics can cause patient sensitivity and bacterial resistance, they should be used only when specifically indicated.

Low Dose Antibiotics

Recently there has been interest in the use of low dose antibiotics. The dose is so low the drug does not act to kill bacteria, but rather to change the way the body responds to infection.

One interesting effect of certain antibiotics is they not only kill the bacteria that may cause periodontal disease, but they also reduce the body’s production of collagenase, an enzyme that destroys gingival tissues. We all need some collagenase as older tissue is removed and replaced with new tissue. However, in periodontal disease there seems to be an overproduction of collagenase, causing the body to destroy healthy gum tissue. The antibiotic doxycycline was found to combat these enzymes, even in doses so small that there was not an antibiotic effect. The advantages of a smaller dose is decreased formation of resistant bacteria and fewer unwanted side effects.

Periostat is a 20 mg capsule of doxycycline, and two clinical studies have shown that patients who take 2 capsules daily have a reduction in clinical inflammation. The studies were limited to 9 months, and so there is no official recommendation to take the product for a longer period. From a practical standpoint it seems that Periostat can be taken indefinitely. However, some preliminary work indicates that there is a positive residual effect for 3 months after stopping the drug, and so some practitioners recommend taking Periostat three months on, three months off. The daily 40mg doses are so low as not to qualify as an antibiotic, and there is no known effect on the pocket bacteria. Thus Periostat must be used in conjunction with other therapies that address bacterial removal. Indications for Periostat are generally seen in recall patients who are not responding well to conventional treatment, and have generalized inflammation in spite of reasonable oral hygiene.

Local Antibiotic Therapy

While systemic antibiotics have a very limited use in treating typical periodontal disease, there has been much interest in local antibiotic delivery. If an antibiotic can be delivered directly to the pocket, without the patient having to take systemic doses, there are far fewer side effects, and fewer chances of resistant bacteria forming. In addition, with direct local delivery, the concentration of the antibiotic at the diseased site can be 100 times greater than taking the medication orally. However, it is important to note that all local delivery antibiotics are recommended as adjuncts to scaling and root debridement, and not as stand-alone treatments. [back to top]

Systemic antibiotics are diluted before reaching the pocket. With local application, the antibiotic is inserted directly into the pocket, resulting in much higher concentrations.


The most recent local antibiotic therapy introduced consists of small spheres of minocycline, a derivative of tetracycline. This drug is very effective in killing the bacteria that are thought to cause periodontal disease. The primary advantage of this new product is the ease of use. The spheres, which look like a fine powder, are contained in a small plastic canula, and are injected into the pocket. This requires no anesthesia. The spheres are bioadhesive, and stick to the pocket wall where they slowly release minocycline over a 14-21 day period. Because the spheres are also bioresorbable, they do not require removal.

Generally speaking, local delivery antibiotics are used in the Periodontal Maintenance phase of therapy, when isolated areas of the mouth seem to be deteorating. Their use is generally not recommended during the active phase of treatment. The effectiveness of these products is somewhat controversial, and while there is usually some improvement, whether their are any long-term benefits has yet to be demonstrated. Certain cases appear to respond better than others, and your periodontist will help advise you whether these treatments may be beneficial in your particular case.

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