The quadruple-blinded, randomised, placebo-controlled trial assessed the effect of either probiotic lozenges or placebo in a group of 80 orally healthy participants, who refrained from oral hygiene for 14 days, followed by 14 days with regular oral hygiene.
“Probiotics support recovery toward a baseline composition of the supragingival microbiota during the resolution of biofilm-mediated gingivitis,” the authors from Denmark, Finland and The Netherlands concluded.
Published in the journal Nutrients, the study was supported financially by the Innovation Fund Denmark, The Danish Dentists Association’s Research Committee and nutrition company ADM Denmark.
Probiotics for gum health
Biofilm-induced gingivitis (inflammation of the gums) affects up to 90% of the population and in most cases is reversible through responsible oral hygiene. It can also be the precursor of periodontitis, a serious gum infection that damages the soft tissue around teeth.
Probiotic supplementation has been suggested as preventative method, and recent studies have tested the potential protective effect of probiotics against gingivitis, however, results remain inconclusive due to the varied probiotic strains used and limited studies.
“Importantly, previous studies have focused on clinical, microbiological, or immunological data without combining them, which complicates the possibility of characterising the full effect of tested probiotics on the oral microbiota and host response," the authors of the new study noted. “Considering that gingivitis is a multifactorial disease that is reflected in clinical, microbiological, and immunological endpoints, there is a need for probiotic studies to characterise the effect on all three parameters.”
Therefore, the authors aimed to assess the efficacy of the probiotic supplement in protecting the oral microbiota through the evaluation of clinical parameters (plaque and bleeding), microbiological composition and immune response activation (cytokines and proteases).
Participants (aged 19–33 years) refrained from all oral hygiene (teeth cleaning) during the initial 14 days (±2 days) of the trial period, resuming regular oral hygiene over the following 14 days (±2 days). The individuals received either a probiotic (a combination of L. rhamnosus PB01 DSM14870 and L. curvatus EB10 DSM32307 combined with xylitol) or a placebo for the full duration of the trial.
The researchers recorded supragingival plaque score and bleeding-on-probing percentage (BOP %) at baseline, day 14 and day 28 and collected supragingival plaque and saliva samples. The supragingival microbiota was characterised using 16S sequencing, and saliva samples were analysed for levels of pro-inflammatory cytokines and proteases.
Results on day 28 showed that the relative abundance of Lautropia, Prevotella, Fusobacterium and Selenomonas genera were significantly higher in the placebo group compared to the probiotics group, while the relative abundance of Rothia species was associated with the probiotics group. In addition, Streptococcus sanguinis was associated with the probiotics group, and Campylobacter gracilis was associated with the placebo group.
“As expected, biofilm-induced gingivitis impacts the composition of the supragingival microbiota by significantly increasing the relative abundance of Lautropia, Fusobacterium, and Selenomonas genera and significantly decreasing the abundance of Rothia," the authors wrote. “These changes were evident in both the placebo and the probiotics groups. Moreover, this is consistent with previous studies demonstrating that Prevotella, Selenomonas, and Fusobacterium genera are associated with gingivitis, while Rothia is associated with oral health.”
“The present study suggests that probiotics support the resilience of the oral microbiota in the resolution period after gingivitis,” they wrote, adding that study limitations included the size of the cohort, which "turned out to be underpowered in terms of the clinical endpoints tested" despite its considerable sample size.
For future research, the study suggested using larger sample sizes to evaluate the clinical effect and noted that results from a young and healthy study population cannot be transferred to an ill or old population with a weakened immune response.
“Probiotics Support Resilience of the Oral Microbiota during Resolution after Experimental Gingivitis—A Randomized, Double-Blinded, Placebo-Controlled Trial”
Authors: Christine Lundtorp Olsen et al.