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Treating Periodontal Diseases as Infections

Walter J. Loesche, DMD, PhD, talks to Dimensions about the use of antibiotics and locally delivered antimicrobials in dentistry.

Q. How are antibiotics and locally delivered antimicrobials used in the treatment of periodontal diseases?

A. Periodontal diseases are pathophysiological responses of the teeth and surrounding structures to the overgrowth of bacteria.1 Basically, many cases of periodontitis are treatable infections. Research shows that in the right patient, some periodontal diseases can be effectively treated with debridement (scaling and root planing) plus systemic antibiotics.2-5 Patients who will benefit from a systemic antibiotic regimen have serious disease status (probing depths greater than 5 mm) and have a diagnosable anaerobic infection. These are typically aggressive forms of periodontitis. Refractory patients (those who have not responded to debridement procedures and access surgery) may also benefit.1

Q. Are antibiotics and locally delivered antimicrobials currently considered part of the treatment plan for periodontal diseases?

A. Their usage has really polarized dentistry. Many dental professionals are opposed to using antibiotics and antimicrobials because they believe they can achieve the best results by scaling and root planing followed, if necessary, by surgical procedures alone. Plus, with regard to the systemic use of antibiotics, there are no proprietary antibiotics unique to the dental market. Companies don’t fund studies to prove the efficacy of generic antibiotics like metronidazole, which is the systemic antibiotic that I used in most of my research. We had to rely on government grants to show in three double blind studies that metronidazole was effective in reducing periodontal surgery needs. Research and funding are abundant with locally delivered antimicrobials. These studies have been performed with great expense and are widely marketed. (See Table 1 for a listing of currently available locally applied and systemic antimicrobials.)

Q. Are antibiotics and locally delivered antimicrobials effective modalities in the treatment of periodontal diseases?

A. The best way to gauge a treatment’s efficacy is to look at the tangible benefits it provides to the patient. A tangible benefit in periodontitis is that the patient keeps his or her teeth with good function and esthetics in the absence of discomfort. The second benefit is that the patient can avoid periodontal surgery. I think that more periodontists are using systemic antibiotics and locally delivered antimicrobials and observing success. At the same time, I think the incidence of periodontal surgery is decreasing.


Q. Is there a danger of overuse of antibiotics in dentistry?

A. Yes, just like in medicine, antibiotics should not be over-used since this could promote the growth of antibioticresistant organisms. We reserve the use of systemic antibiotics for patients whose disease is serious enough to warrant periodontal surgery and in those whom we can diagnose an anaerobic infection. The infection in periodontal disease is due to an overgrowth of organisms called anaerobes. Because they are anaerobes, I use the antibiotic metronidazole that is specific to anaerobes and I prescribe it for 1 to 2 weeks, after initial debridement. A good rule for antibiotic use is that if it doesn’t work in 1 or 2 weeks, it’s not the right antibiotic. Dental professionals need to be careful about who they treat with antibiotics. One of the problems is that dental/ dental hygiene schools do not teach students how to use systemic antibiotics. Students do not get guidance on dosages or the different types of antibiotics available.


Q. Are there advantages to using locally delivered antimicrobials?

A. Yes, there are advantages in using locally delivered antimicrobials vs systemic antibiotics. The most obvious and most important is compliance. If a patient is prescribed a systemic antibiotic that requires him or her to take it three times a day for 1 or 2 weeks, many patients will not be compliant. In medicine, compliance is only about 40% to 50% with prescription medications. 6 With locally delivered agents, the compliance problem is eliminated. The dental professional places the locally delivered product, whether it’s a polymer, gel, or chip, in the pocket. The second advantage of locally delivered antimicrobials is that their dosages can be very high but the exposure of the whole body to the antibiotic is very low so side effects are not of concern. For example, patients are advised to abstain from drinking alcoholic beverages when taking metronidazole. This is a disincentive for compliance for many people but if the antibiotic is delivered locally, the dosage throughout the whole body is so low that this warning is unnecessary. Patient compliance and the absence of side effects are major benefits to locally delivered antimicrobials. The downside of locally delivered antimicrobials is that each pocket that is involved must be treated. In a patient with an extensive periodontal disease, he or she may need 24 sites treated. This takes time and is expensive. I think locally delivered antimicrobials work best in patients with a finite number of sites that need treatment.

Q. Do you foresee any advancements in the use of antibiotics?

A. There will never be a systemic antibiotic developed specifically for dentistry because the cost is too prohibitive. However, the systemic antibiotic azithromycin is becoming more popular in dentistry and periodontics. This drug only needs to be taken once per day for 3 days, which can help with the compliance problem.

However, it is expensive. In 2007, azithromycin became a generic drug so it may go down in price. I think more den tists/ periodontists will probably use this agent in the future.

TABLE 1. Currently Available Locally Delivered Antimicrobials

OraPharma Inc, Warminster, Pa
Subgingival sustained release antibiotic containing 1 mg of minocycline hydrochloride that is incorporated into microspheres, a bioresorbable polymer for subgingival application. ARESTIN is indicated for application both at the time of initial scaling and root planing and for maintenance in pockets deeper than 5 mm.

TOLMAR Inc, Fort Collins, Colo
An antimicrobial gel containing doxycycline that flows deeply into the periodontal pockets solidifying into a wax-like substance in minutes, administered with a syringe.

MIS Implants Technologies Ltd (United States distributor), Fair Lawn, NJ PerioChip is a small rectangular chip composed of 2.5 mg chlorhexidine D-gluconate in a biodegradable matrix of hydrolyzed gelatin, cross linked with glutaraldehyde, that is inserted into periodontal pockets that are at least 5 mm deep.


  1. Loesche WJ. The anti microbial treatment of periodontal disease: changing the treatment paradigm. Crit Rev Oral Biol Med. 1999;10:245-275.
  2. Loesche WJ, Grossman NS. Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment. Clin Microbiol Rev. 2001;14:727-752.
  3. Loesche WJ, Giordano JR. Treatment paradigms in periodontal disease. Compend Contin Educ Dent. 1997;18:221-226, 228-230.
  4. Loesche WJ. The therapeutic use of antimicrobial agents in patients with periodontal disease. Scand J Infect Dis Suppl. 1985;46:106-114.
  5. Loesche WJ. The specific plaque hypothesis and the antimicrobial treatment of periodontal disease. Dent Update. 1992;19:68, 70-2, 74.
  6. Claxton AJ, Cramer J, Pierce C. A systematic review of the associations between dose regimens and medication compliance. Clin Ther. 2001; 23: 1296-1310.

From Dimensions of Dental Hygiene. June 2008;6(6): 28, 31.

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