Introduction:
The aim of this study is to evaluate the efficacy of oral administration of synbiotic tablets on the clinical parameters and the levels of selected inflammatory mediators in gingival crevicular fluid (GCF) in smokers and non-smokers with gingivitis.

Methods:
Eighty patients with gingivitis (40 smoker (+), 40 non-smoker (-)), randomly assigned to test (T) or control (C) groups. Each subject was instructed to chew one tablet per day, during 30 days. Clinical parameters including plaque and gingival indices and GCF samples obtained from all subjects on baseline, 1st month, and 2nd month. The GCF levels of interleukin (IL)-6, IL-8 and IL-10 were determined.

Results:
All clinical and biochemical parameters for all groups were significantly reduced compared to baseline (p<0.05). GCF volume didn’t show a significant intergroup difference at any time whereas Plaque Index (PI) was significantly higher in both smoker groups compared with the T(-) group in the 2nd month follow-up (p<0.05). GCF levels of IL-8 in C(-) group, IL-6 in both control groups were significantly higher compared to T(+) group and IL-10 in both control groups were significantly higher compared to T(-) group at the 2nd month follow up (p<0.05).

Conclusions:
Adjunctive synbiotic tablets enhance subclinic therapeutic outcomes regardless of smoking compared with placebo according to the levels of IL-6, IL-8 and IL-10 variables.