Objectives: Evaluation of the clinical effect of topical subgingival application of doxycycline gel adjunctively to scaling and root planing (SRP) at furcation sites during supportive periodontal therapy (SPT).
Material and methods: In 39 SPT patients exhibiting at least four pockets > or m with bleeding on probing, SRP was rendered in all pockets > or m. Additionally, 14% doxycycline gel was applied subgingivally in 20 patients after random assignment (SRP&DOXY). Clinical parameters were assessed at baseline, 3, 6, and 12 months after therapy. Additional benefit of topical doxycycline was evaluated as a short-term (3 months) improvement of furcation involvement and influence on the frequency of re-instrumentation up to 12 months.
Results: A total of 323 furcation sites (class 0: 160; class I: 101; class II: 18; and class III: 44) were treated (SRP: 165, SRP&DOXY: 158). SRP&DOXY resulted in better improvement of furcation involvement than SRP alone 3 months after treatment (p=0.041). However, SRP&DOXY failed to show a significant difference between both groups in the number of re-instrumentations.
Conclusion: Single subgingival application of doxycycline in addition to SRP had a short-term effect on furcation involvement. However, it failed to reduce the frequency of re-instrumentation up to 12 months at furcation sites.