Effect of tablets containing probiotic candidate strains on gingival inflammation and composition of the salivary microbiome: a randomised controlled trial

Abstract

The aim of the study was to investigate clinical and microbial effects of probiotic candidate strains in patients with moderate gingivitis. The null hypothesis was that the clinical measurements with treatment would not differ from placebo. 47 adult patients were enrolled in a randomised placebo-controlled trial with a 4-week intervention of tablets containing a mix of Lactobacillus rhamnosus PB01, DSM 14869 and Lactobacillus curvatus EB10, DSM 32307 or placebo. Clinical examinations and samplings were done at baseline and after 2, 4 and 6 weeks. The clinical endpoints were general bleeding on probing (BOP), general plaque index (PI) and flow of gingival crevicular fluid (GCF). In addition, the concentration of selected cytokines (interleukin (IL)-1β, IL-6, IL-8, IL-10, tumour necrosis factor alpha (TNF-α)) in GCF was determined with multiplex immunoassays. The profiles of the salivary microbiome were analysed with Next Generation Sequencing (NGS) and qPCR. In contrast to the placebo group, there was a significant reduction in BOP and amount of GCF (P<0.05) after 4 weeks in the probiotic test group when compared with baseline. The general PI was less affected although there was a tendency of decreased plaque levels in the probiotic group (P=0.05-0.09). The cytokines were unaffected by the intervention as well as the salivary microbiome. The Shannon index showed no significant differences between the groups or alterations over time. The occurrence of both probiotic strains increased in saliva of the test subjects during the intervention but returned to baseline levels within 2 weeks. Although a marked improvement in gingival health was recorded in the probiotic group, the null hypothesis could not be rejected.

Clinical efficacy of probiotics in the treatment of gingivitis: A systematic review and meta‐analysis

“…In almost 50% of the included studies, clinical periodontal inflammatory parameters showed significant improvements in the test group as compared to control group at follow‐up. Five studies reported comparable clinical inflammatory parameters between test and control groups at follow‐up …”

“…From these 25 articles, 15 studies were subsequently eliminated. The final stage of selection yielded 10 articles to be included and were therefore processed for data extraction ( ĸ : 0.94 [0.89–0.99]) . The selected studies were conducted at university hospitals.…”

“…Information regarding funding sources (Government or university) was not reported in three studies (Table ) . None of the study participants in the included studies experienced any side effects related to probiotic administration …”

“…All selected studies were RCTs. However, three studies did not state anything about sequence generation, while two trials did not describe about allocation methods . Only six trials reported about methods of allocation concealment .…”

“…All studies reported about patients completing clinical trials, and the details about dropouts either in the flow chart or main text except one study . Of all RCTs assessed, the overall risk of bias was considered high in five clinical trials …”