Background and objectives: This study was designed to evaluate whether the oral administration of lactobacilli could change the bacterial population in subgingival plaque.
Subjects and methods: Forty-two healthy volunteers with chronic generalized mild to moderate periodontitis were given a probiotic drink containing Lactobacillus casei for 1 month. Subgingival plaque samples were collected at baseline, after which the patients were asked to consume the probiotic drink once daily for 1 month. At the 1 month interval, plaque samples were collected, and the drink discontinued. The patients were recalled at 2 months interval for collection of the final samples. The bacterial amounts in the plaque samples were analyzed by multiplex polymerase chain reaction procedure.
Results: Of the three periodontopathic bacteria selected, Porphyromonas gingivalis showed highly significant reductions in the bacterial levels at 1-month and 2 months intervals. In comparison, Aggregatibacter actinomycetemcomitans, when present higher than 10 × 10(3) at baseline, and Prevotella intermedia present higher than 2 × 10(3) at baseline, showed moderately significant reduction in their numbers.
Interpretation and conclusion: Oral administration of the probiotic lactobacilli reduced the numerical sum of the three selected periodontopathic bacteria and could contribute to the beneficial effects on periodontal conditions.