Abstract
Background and aims. Periodontal disease is a complex interaction between bacteria and susceptible host. MMPs has
a key role in periodontal disease and increase with disease severity which cause destruction of extra cellular matrix in
chronic periodontitis. HMT is a therapeutic hypothesis which its objection is the reduction of tissue destrucion.
Doxycyclines can inhibit MMPs activation through the synthesis of intracellular enzymes. The objective of this study was
to evaluate the Effectiveness of adjunctive Subantimicrobial Dose Doxycycline on phase I of periodontal therapy.
Materials and methods. Forty patients with chronic periodontitis were included in this randomized double blind placebo
control parallel group clinical study. After scaling and root planning patients were randomly assigned to two groups,
receiving either SDD or placebo bid for 3 months and were evaluate in 3month and 6 month later.
Results. Clinical parameter improved significantly in both groups (p-value˂0.0001). Significant reduction in PD, CAL
and BOP was seen in SRP +SDD group compare to control group (p-value˂0.0001).
Conclusion. Short administration of SDD gives significant benefit in clinical parameters in chronic periodontitis.