Meta-analysis of the effect of systemic metronidazole as an adjunct to scaling and root planing for adult periodontitis

The purpose of this meta-analysis was to provide a quantitative overview of clinical trials assessing the use of systemic metronidazole (S-MET) as an adjunct to scaling and root planing (S&RP) in the treatment of adult periodontitis. Eight clinical trials were chosen based upon a priori selection criteria, and two outcomes, ''reduction in probing pocket depth'' (PD) and ''gain in clinical attachment level'' (CAL), were analyzed. Results for each outcome were stratified by initial PD 1-3 mm, 4-6 mm, or greater than or equal to 7 mm and length of follow-up 4-6 wk, 9-13 wk, or 14-26 wk. S-MET in conjunction with S&RP was superior to S&RP alone in reducing PD where initial PD was 4-6 mm and follow-up was 9-13 wk (0.43 mm; 99% CI 0.12, 0.73). No significant advantage was observed for S-MET for reducing PD where initial PD was less than 4 mm or follow-up was longer than 13 wk. S-MET in conjunction with S&RP was superior to S&RP alone in reducing CAL where initial PD was 4-6 mm and follow-up was 4-6 wk (0.29; 99% CI 0.01, 0.58) and where follow-up was 9-13 wk (weighted mean difference 0.32; 99% CI 0.03, 0.61). Significant heterogeneity of effect was not seen for PD or Cal at any level of initial PD or length of follow-up. No significant dose-response relationship was observed. This meta-analysis was limited due to diversity of data presentation and the small number of trials in each stratum. These results suggest that S-MET in conjunction with S&RP may offer a benefit over S&RP alone in the treatment of adult periodontitis patients in managing pockets of 4 mm or greater, but the additional benefit was not evident if initial PD was less than 4 mm or follow-up was beyond 13 wk.