Abstract
The oral cavity plays a crucial role in food digestion and immune protection. Thus, maintaining oral health is necessary. Postbiotic and heat-killed probiotic cells have shown increased antibacterial potential with stable viability compared with live strains. However, clinical evidence regarding their effect on oral health is insufficient. Therefore, in this study, we tested postbiotic lozenges of Lactobacillus salivarius subsp. salicinius AP-32, L. paracasei ET-66, and L. plantarum LPL28 and heat-killed probiotic lozenges of L. salivarius subsp. salicinius AP-32 and L. paracasei ET-66 for their effect on oral health. In total, 75 healthy individuals were blindly and randomly divided into placebo, postbiotic lozenge, and heat-killed probiotic lozenge groups and were administered the respective lozenge type for 4 weeks. Postbiotic and heat-killed probiotic lozenge groups demonstrated antibacterial activities with a considerable increase in L. salivarius in their oral cavity. Furthermore, their salivary immunoglobulin A, Lactobacillus, and Bifidobacterium increased. Subjective questionnaires completed by the participants indicated that participants in both the experimental groups developed better oral health and intestinal conditions than those in the placebo group. Overall, our study revealed that a food additive in the form of an oral postbiotic or heat-killed probiotic lozenge may effectively enhance oral immunity, inhibit the growth of oral pathogens, and increase the numbers of beneficial oral microbiota.
Highlights
The mucosal immune system of the oropharyngeal cavity, which is the opening gate for digestive and respiratory systems, plays a crucial role in preventing pathogen entry into the human body [1]
Based on previous in-vitro screening of viable probiotic strains for improving oral health, we further investigated whether heat-killed probiotic (ET-66 and AP-32), and postbiotic lozenges (LPL28, ET-66, and AP-32) modulate oral microbiota, inhibit oral infectious pathogens, and change salivary immunoglobulin A (IgA) levels [22, 23]
The inhibition rates of A. actinomycetemcomitans were significantly higher with the use of the postbiotics of AP-32 (17.92%, p < 0.05), ET-66 (77.86%, p < 0.001), and LPL28 (24.28%, p < 0.001) than with the use of L. rhamnosus GG (LGG) postbiotic (13.69%)
Summary
The mucosal immune system of the oropharyngeal cavity, which is the opening gate for digestive and respiratory systems, plays a crucial role in preventing pathogen entry into the human body [1]. Firmicutes, Actinobacteria, Proteobacteria, Fusobacteria, Bacteroidetes, and Spirochaetes constitute 96% of all oral bacterial phyla [2, 3]. Oral microbes colonize the oral www.aging-us.com cavity as a biofilm, which regulates oral homeostasis, oral immunity, food digestion, detoxification, inflammatory processes and is involved in disease prevention [5, 6]. Dewhirst et al demonstrated major oral microbial phylum were Firmicutes (36.7%), Bacteroidetes (17.3%), Proteobacteria (17.1%), Actinobacteria (11.6%), Spirochaetes (7.9%), Fusobacteria (5.2%) [7]. Poor oral hygiene may cause oral microbiota dysbiosis, which leads to dental bacterial plaque, gingivitis, and periodontitis [8]. Studies have shown that live probiotic strains inhibit oral pathogens and are the rationale for periodontal treatment; they are similar to antibiotics but without the major concern of antimicrobial resistance [14]. Metabolites of viable probiotic strains (postbiotic) such as 10-Hydroxy-cis-12-octadecenoic acid and heat-inactivated probiotics have shown the potential to alleviate the disruption of the gingival epithelial barrier caused by periodontitis [16]
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