Effect of Lactobacillus rhamnosus L8020 on the abundance of periodontal pathogens in individuals with intellectual disability: A randomized clinical trial.

Gingivitis refers to inflammation of the gingiva and its connective tissues. Research has revealed a higher prevalence of gingivitis in individuals with intellectual disability (ID) than in healthy individuals. Milk fermented with Lactobacillus rhamnosus L8020 (L8020 yogurt) inhibits the accumulation of periodontal disease-related pathogens in vitro and alleviates the symptoms of periodontal disease. The aim of this study was to investigate the influence of L8020 yogurt on oral microbiota and the abundance of four periodontal pathogens (Tannerella forsythia, Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola) and on the microbiota in individuals with ID and gingivitis.Forty-one outpatients with ID participated in this study. To examine the effects of daily consumption of L8020 yogurt, the patients were randomly divided into L8020 (test group, n = 21) and placebo (n = 20) yogurt groups. All patients consumed 80 g of yogurt for 12 weeks. Oral examination was performed before the first intake of yogurt and dental plaque was collected before and after the intake of yogurt. DNA was extracted from dental plaque and subjected to next-generation sequencing.The relative abundance of T. forsythia was significantly lower in the test group than in the placebo group. Additionally, the relative abundance of the four pathogens reduced after 84 days of consuming L8020 yogurt compared with that after consuming placebo yogurt.Mixing L. rhamnosus L8020 with probiotic products that are consumed daily would be effective in suppressing the increase in periodontal disease-causing bacteria and beneficial for individuals with ID.