Meta-analysis of the association between serum and gingival crevicular fluid matrix metalloproteinase-9 and periodontitis.

BACKGROUND: The authors of this meta-analysis evaluated whether there is a difference in the levels of serum and gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-9 between patients with periodontitis and periodontally healthy control participants. TYPES OF STUDIES REVIEWED: The authors searched PubMed, Embase, the Cochrane Library, and the China Biology Medicine disk databases for eligible studies in which the investigators reported the relationships between MMP-9 levels in serum and GCF and periodontitis. The authors pooled the standardized mean differences (SMDs) and 95% confidence intervals (CIs) from each study to evaluate the difference in the serum and GCF MMP-9 levels between patients with periodontitis and periodontally healthy control participants. RESULTS: Results of a meta-analysis of 6 case-control studies including a total of 923 healthy control participants and 557 patients with periodontitis indicated that serum MMP-9 levels were significantly higher in patients with periodontitis than in periodontally healthy control participants (SMD, 1.60; 95% CI, 0.17 to 3.03; P < .05). Results of a separate meta-analysis of 6 case-control studies including a total of 153 healthy control participants and 189 patients with periodontitis indicated that GCF MMP-9 levels were significantly higher in patients with periodontitis than in periodontally healthy control participants (SMD, 1.96; 95% CI, 0.76 to 3.16; P < .01). CONCLUSIONS AND PRACTICAL IMPLICATIONS: The results of the meta-analysis revealed statistically significant differences in the MMP-9 levels in serum and GCF between patients with periodontitis and periodontally healthy control participants. These results cannot be used to confirm causality because the included studies were all case-control studies in which the investigators reported associations. Moreover, readers should view the results with caution because of the considerable heterogeneity among the studies included in the meta-analysis.