ABSTRACT
OBJECTIVE: A randomized, double-blind, placebo-controlled crossover comparative study was conducted in a healthy older population to assess the usefulness of Lactobacillus salivarius WB21 (WB21) ingestion for oral self-care. METHODS: The study population included 33 healthy older individuals who were randomly divided into two groups (A and B). Group A consumed WB21 tablets during the first two months and placebo tablets during the following two months. Group B consumed placebo tablets during the first two months and WB21 tablets during the following two months. Before and after ingestion, oral examination, mouth odor test, and saliva collection were performed a total of four times. In addition, health conditions were obtained from a questionnaire survey at the study's midpoint. RESULTS: Two people in group A and one person in group B dropped out of the study. Thus, 15 people in group A and 15 people in group B were included in the analysis. Over two months of WB21 ingestion, salivary secretory IgA increased significantly (p = 0.047) and tongue coating score decreased significantly (p = 0.013). The plaque index, bleeding on probing, and mouth odor levels (H2S and CH3SH concentrations) did not change. During the 6-month study period, no caries, deterioration of periodontitis, or changes in oral health or systemic subjective symptoms were observed. CONCLUSION: Continuous ingestion of WB21-containing tablets may promote self-care of the teeth and mouths of healthy older adults. TRIAL REGISTRATION: R000028335 (UMIN-CTR).