Improvement of periodontal condition by probiotics with Lactobacillus salivarius WB21: A randomized, double-blind, placebo-controlled study

Aim: This randomized clinical study was designed to evaluate the effect of probiotic intervention using lactobacilli on the periodontal condition of volunteers without severe periodontitis. Material and Methods: Freeze-dried Lactobacillus salivarius WB21 (WB21)-containing tablets or a placebo were given to volunteers in a double-blind randomized study. A total of 66 volunteers were finally enrolled and randomly assigned to receive tablets containing WB21 (6.7 × 10⁸ CFU) with xylitol or xylitol alone (placebo) three times a day for 8 weeks. Periodontal clinical parameters and whole saliva samples were obtained at baseline (BL), 4 weeks, and the end of the interventional period (8 weeks). Salivary lactoferrin (Lf) levels were measured by enzyme-linked immunosorbent assay. Lactobacilli in saliva and plaque samples was detected by semi-quantitative RT-PCR using 16S rRNA primers. Results: Periodontal clinical parameters were improved in both groups after an 8-week intervention. Current smokers in the test group showed a significantly greater improvement of plaque index and probing pocket depth from BL when compared with those in the placebo group. Salivary Lf level was also significantly decreased in the test group smokers. Conclusion: Our results indicate that probiotics could be useful in the improvementmaintenance of oral health in subjects at a high risk of periodontal disease.