The efficacy of adjunctive SDD on both clinical parameters and GCF MMP-8, MMP-9, MMP-13, MPO, TRAP, and OPG levels beyond that obtained by nonsurgical periodontal therapy alone in chronic periodontitis patients has been investigated in the present double blind, placebo-controlled, parallel-arm study. The gene discussed is TNFRSF11B; the disease is chronic periodontitis.