Localized Antibiotic Administration
Antibiotics are drugs which, when prescribed at traditional doses, either kill or prevent reproduction of bacteria. Antibiotics are important in dentistry, because most dental illness (including tooth decay and periodontal disease) is caused by bacteria. Antibiotics are not designed to kill viruses or fungi, although some of those organisms may be susceptible to certain antibiotics.
There are many different types of antibiotics, which function in different ways and target specific types of bacteria. For example, the penicillin family of antibiotics share a functional molecule called a beta lactam ring, which binds to certain bacteria and prevents them from being able to build the cell wall necessary for their survival.
Through many years of over-prescription, some bacteria have developed resistance to certain antibiotics (including the penicillin family). To overcome this, new methods of delivering antibiotic drugs only to infected tissue (instead of system-wide) have been developed, along with ways to prevent the undesirable activity of bacteria, without killing them outright. Suppressing a certain species of bacteria with antibiotics can allow unsusceptible species to flourish, upsetting the delicate balance that exists among the species that live in our mouths, stomach, and intestines. It can also encourage the targeted bacteria to mutate into forms which are resistant to antibiotic treatment.
An example of this newer technology is the use of low-dose doxicycline (20mg) to suppress human-generated enzymes that form in response to bacteria from destroying the periodontal tissues (gums and bone). At this dose, the bacteria themselves are not killed or prevented from reproducing, but their harmful activity is halted. Because the balance of bacterial flora is not being altered, it is believed that the drug may be safely taken in pill form without the risk of resistant strains of bacteria developing. This drug is commonly used as a supplement to traditional periodontal treatment to control periodontal disease (periodontitis).
Another relatively new method of preventing tissue-destroying bacterial activity around the teeth is to place antibiotics into gum pockets around the teeth in any of several time-release systems that are currently available. This is commonly being done as a supplemental procedure to traditional periodontal treatment, such as scaling and root planing.
When scaling and root planing alone does not decrease inflammation of the periodontal structures, treatment of the gum pocket(s) with locally applied, time-release antibiotics may be prescribed. Some dentists prescribe the antibiotics at the time scaling and root planing is performed, believing that those bacteria which are not removed through mechanical debridement will be killed or prevented from multiplying by the drug.
Opponents of this concurrent treatment protocol cite it as a sort of belt-and-suspenders overtreatment approach. However, with many studies showing that scaling and root planing alone is not completely effective at removing all of the calculus and diseased cementum, localized antibiotic administration may be a good thing to consider. This is especially true in deeper pockets, where some studies show that scaling and root planing may remove as little as 11% of the calculus!
Localized antibiotic administration may not help individuals with aggressive periodontitis, and has been shown to be most effective in adults with chronic, localized periodontitis.