Abstract
Streptococcus dentisani 7746, isolated from dental plaque of caries-free individuals, has been shown to have several beneficial effects in vitro which could contribute to promote oral health, including an antimicrobial activity against oral pathogens by the production of bacteriocins and a pH buffering capacity through ammonia production. Previous work has shown that S. dentisani was able to colonize the oral cavity for 2–4 weeks after application. The aim of the present work was to evaluate its clinical efficacy by a randomized, double-blind, placebo-controlled parallel group study. Fifty nine volunteers were enrolled in the study and randomly assigned to a treatment or placebo group. The treatment consisted of a bucco-adhesive gel application (2.5 109 cfu/dose) with a dental splint for 5 min every 48 h, for a period of 1 month (i.e., 14 doses). Dental plaque and saliva samples were collected at baseline, 15 and 30 days after first application, and 15 days after the end of treatment. At baseline, there was a significant correlation between S. dentisani levels and frequency of toothbrushing. Salivary flow, a major factor influencing oral health, was significantly higher in the probiotic group at day 15 compared with the placebo (4.4 and 3.4 ml/5 min, respectively). In the probiotic group, there was a decrease in the amount of dental plaque and in gingival inflammation, but no differences were observed in the placebo group. The probiotic group showed a significant increase in the levels of salivary ammonia and calcium. Finally, Illumina sequencing of plaque samples showed a beneficial shift in bacterial composition at day 30 relative to baseline, with a reduction of several cariogenic organisms and the key players in plaque formation, probably as a result of bacteriocins production. Only 58% of the participants in the probiotic group showed increased plaque levels of S. dentisani at day 30 and 71% by day 45, indicating that the benefits of S. dentisani application could be augmented by improving colonization efficiency. In conclusion, the application of S. dentisani 7746 improved several clinical and microbiological parameters associated with oral health, supporting its use as a probiotic to prevent tooth decay.
Highlights
Oral diseases, including dental caries, periodontitis, and halitosis are among the most prevalent diseases worldwide (Petersen, 2008)
The species at significantly higher levels in the probiotic group at the end of treatment compared to placebo comprised Gemella morbillorum, Porphyromonas pasteri, and Kingella sp. These results showed that treatment with S. dentisani probiotic results in a microbial shift in composition which is consistent with a healthier microbiota, as there is a decrease of microorganisms associated with dental caries such as Scardovia wiggsiae (Tanner et al, 2011), Actinomyces sp., Veillonella sp. (Belda-Ferre et al, 2012; Simón-Soro et al, 2014), and Atopobium parvulum (Obata et al, 2014); a decrease in bacteria associated with periodontal diseases and halitosis such as Dialister (Silva-Boghossian et al, 2013), Prevotella (CameloCastillo et al, 2015), and Fusobacterium nucleatum (Wang et al, 2019); and an increase in some bacteria associated with oral health such as Gemella (Luo et al, 2012) and Kingella (BeldaFerre et al, 2012)
The randomized, double-blind, placebo-controlled clinical study reported in the current manuscript has evaluated the effect of the probiotic S. dentisani strain 7746 buccoadhesive gel administration on several clinical and microbiological parameters, which are directly or indirectly related to oral health, specially tooth decay
Summary
Oral diseases, including dental caries (tooth decay), periodontitis (gum disease), and halitosis (bad breadth) are among the most prevalent diseases worldwide (Petersen, 2008) All these conditions are caused by microorganisms, current data indicate that they are not caused by exogenously acquired organisms, as healthy individuals already contain low levels of the microorganisms identified as causing agents and oral diseases do not develop as a consequence of being infected by those microbes (Bradshaw and Lynch, 2013; CameloCastillo et al, 2015; Simón-Soro and Mira, 2015). Recent views in preventive dentistry suggest shifting from antimicrobial strategies toward the development of products that can restore the balance in the oral ecosystem (Marsh, 2018; Mira, 2018), and these include the use of prebiotics and probiotics (Koduganti et al, 2011)
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