Clinical evaluation of local antibiotic treatment in smokers with chronic periodontitis in a maintenance care program. Authors: Kerstin Stagnér, Gunilla Bratthall. Institution Department of Periodontology, Faculty of Odontology, Malmö University. Aim. To evaluate if local antibiotics, 8.8 % doxycycline gel, can improve periodontal healing in smoking adults in a maintenance care program. Material and Methods. In a double-blind randomized controlled study 20 smoking patients were selected from a maintenance care program. Each subject demonstrated at least 5 probing pocket depths (PPD) ≥ 5mm with bleeding on probing (BOP) in a minimum of 5 teeth. The patients were divided into 2 groups, the test group (8.8 % doxycycline gel, Atridox®) and the control group (placebo gel). At baseline and 3 months after treatment a clinical registration was performed, including PPD, clinical attachment level (CAL), BOP, and plaque index (PlI) at 4 sites of test- and control teeth. Gingival index (GI) was performed using Periotron® at 2 sites of all index-teeth. At baseline all subjects received full-mouth scaling followed with application of test or placebo gel in all index pockets. After gel application 0.1 % chlorhexidine was used for mouth rinsing during 7-10 days, since no mechanical oral hygiene was allowed during that period. Results. There were 16 patients left in the end of the study. Four subjects in the test group had to be excluded because of disease. Three months after treatment significant improvement for PPD was shown both in the test (p=0.0313) and the control group (p=0.0020). Significant improvement for the control group was also demonstrated for CAL and BoP. There were no significant differences in any parameter in the change after 3 months between test - and control groups. When the results from all teeth (including index teeth) were analyzed significant improvement was shown in PPD both in the test (p=0.0313) and the control group (p=0.0039). Significant improvement for the control group was also demonstrated for CAL, BOP and GI. There were no significant differences between test and placebo treated dentitions. Conclusion. This study could not show any statistically significant clinical differences between the test - and control groups based on results of index teeth as well as all teeth. This means that local antibiotic treatment with 8.8 % doxycycline gel (Atridox®) did not show any additional effects to scaling. The results, however, showed significant improvement of periodontal pockets after subgingival scaling in both test- and control groups.