The effect of adjunctive low-dose doxycycline and licorice therapy on gingival crevicular fluid matrix metalloproteinase-8 levels in chronic periodontitis

Abstract

Background: This study compared the effect of adjunctive low dose doxycycline and licorice on

gingival crevicular fluid (GCF) matrix metalloproteinase-8 (MMP-8) levels in patients with chronic

periodontitis.

Materials and Methods: In this in vivo, experimental study 39 patients with mild to moderate

chronic periodontitis were selected. Samples of GCF were collected from three deepest pockets

and MMP-8 concentration was measured. Patients were divided into three groups (n = 13). Groups

were treated with doxycycline, licorice and placebo. Sampling and measurement of MMP-8 was

repeated after 6 weeks. Data was analyzed by t-paired and ANOVA test. P < 0.001 was considered

significant.

Results: The decrease in mean of MMP-8 concentration was higher in doxycycline and licorice group

in comparison with the placebo group and the difference was statistically significant (P value < 0.001).

The decrease in mean of MMP-8 concentration was higher in licorice group than doxycycline group,

but the difference was not statistically significant.

Conclusion: The present study showed that licorice extract can prevent the production of MMPs

by host cells and can be as useful as antibiotics like doxycycline to cure periodontal and other

inflammatory diseases. It must be added that no side-effects were observed in usage of licorice extract.

Key Words: Chronic periodontitis, doxycycline, gingival crevicular fluid, licorice, matrix

metalloproteinase enzymes-8