Periodontal diseases are infections and thus systemically administered antibiotics are often employed as adjuncts for their control. There are conflicting reports as to whether these agents provide a therapeutic benefit. The purpose of this systematic review is to determine whether systemically administered antibiotics improve a primary clinical outcome measure, periodontal attachment level change. In patients with periodontitis, what is the effect of systemically administered antibiotics as compared to controls on clinical measures of attachment level? The Pub/Med database was searched from 1966 to May 2002. Searches were limited to human studies published in English. Hand searches were performed on the Journal of Clinical Periodontology, Journal of Periodontology, and Journal of Periodontal Research. References in relevant papers and review articles were also examined. Trials were selected if they met the following criteria: randomized controlled clinical trials, quasi-experimental studies, and cohort studies of > 1 month duration with a comparison group; subjects with aggressive, chronic, or recurrent periodontitis and periodontal abscess; use of a single or a combination of systemically administered antibiotics(s) versus non-antibiotic therapy; and a primary outcome of mean attachment level change (AL). Studies involving the use of low-dose doxycycline, combinations of locally plus systemic antibiotics, or where the control group included a systemically administered antibiotic were excluded. A mean difference in AL between groups was available for all papers used in the meta-analysis. A standard deviation (SD) for the difference was used if provided or calculated from the SD or standard error of the mean (SEM) when provided for single measurements. Data were subset by antibiotic employed, type of adjunctive therapy, and disease type. Results were assessed with both fixed-effects and random-effects models. 1. Twenty-nine studies, 26 RCTs and 3 quasi-experimental (36 comparisons), met the entry criteria. Total study population, both control and test groups, was estimated at over 1,200. 2. Twenty-two studies (27 comparisons) were used in the meta-analysis, evaluating if the antibiotics provided a consistent benefit in mean AL change for different patient populations, for different therapies, and for different antibiotics. 3. For the majority of the comparisons, systemically administered antibiotics exhibited a more positive attachment level change than the control group in the study. The combined results were statistically significant (P < 0.001). 4. The systemic antibiotics were uniformly beneficial in providing an improvement in AL when used as adjuncts to scaling and root planing (SRP) and were consistently beneficial, although of borderline significance, when used as adjuncts to SRP plus surgery or as a stand alone therapy. 5. When examining the effects of individual or combinations of antibiotics, it was found that there were statistically significant improvements in AL for tetracycline, metronidazole, and an effect of borderline statistical significance for the combination of amoxicillin plus metronidazole. 6. Improvements in mean AL were consistent for both chronic and aggressive periodontitis subjects, although the aggressive periodontitis patients benefited more from the antibiotics. 1. The use of systemically administered adjunctive antibiotics with and without SRP and/or surgery appeared to provide a greater clinical improvement in AL than therapies not employing these agents. 2. The data supported similar effect sizes for the majority of the antibiotics; therefore, the selection for an individual patient has to be made based on other factors. 3. Due to a lack of sufficient sample size for many of the antibiotics tested, it is difficult to provide guidance as to the more effective ones.
