LAUSR

ABSTRACT Objective This prospective clinical study aim was to analyze the effect of the probiotic Lactobacillus reuteri Prodentis lozenges on salivary microbiome of subjects wearing fixed orthodontic appliances. Methods Saliva samples were collected prior to consumption and 14th-day post probiotic lozenges consumption (n=40, age 18–23). Oral hygiene index-score (OHI-S) and papilla bleeding index (PBI) were recorded. The salivary microbiome was profiled by next-generation sequencing using the V3-V4 region of 16S-rRNA. Microbial composition, diversity and taxonomic biomarkers were analysed in comparison to probiotic intervention and the clinical characteristics of the cohort using standard bioinformatics tools. Results The diversity and bacterial community structures did not change significantly in salivary microbiome of periodontally healthy subjects during short-term probiotic intervention. Probiotic consumption correlated with reduction of OHI and PBI scores (50% reduction of scores, P<0.001). The reduction of clinical indices was evident in conjunction with significantly reduced abundance of oral pathogens, such as Porphyromonas pasteri, Treponema sp., Fretibacterium fastidiosum, Kingella oralis and Propionibacterium acnes. Conclusion Short-term probiotic intervention helped maintaining good oral health in patients undergoing fixed orthodontic therapy. Although overall oral microbiome structure remained largely unchanged, a significant alteration in the abundance of health and disease-associated species highlighted the beneficial effect of probiotic.