We aimed to assess the effect of oral probiotics containing the Streptococcus salivarius K12 strain on the salivary level of secretory immunoglobulin A, salivation rate, and oral biofilm. Thirty-one consenting patients meeting the inclusion criteria were recruited in this double-blind, placebo-controlled, two-arm, parallel-group study and randomly divided into probiotic (n = 15) and placebo (n = 16) groups. Unstimulated salivation rate, concentration of salivary secretory immunoglobulin A, Turesky index, and Papillary-Marginal-Attached index were assessed after 4 weeks of intervention and 2 weeks of washout. Thirty patients completed the entire study protocol. We found no increase in salivary secretory immunoglobulin A levels and salivary flow rates in the probiotic group compared with placebo. Baseline and outcome salivary secretory immunoglobulin A concentrations (mg/L) were 226 ± 130 and 200 ± 113 for the probiotic group and 205 ± 92 and 191 ± 97 for the placebo group, respectively. A significant decrease in plaque accumulation was observed in the probiotic group at 4 and 6 weeks. Within the limitations of the present study, it may be concluded that probiotic intake (Streptococcus salivarius K12) does not affect salivation rates and secretory immunoglobulin A salivary levels but exhibits a positive effect on plaque accumulation. Trial registration NCT05039320. Funding: none.

We aimed to assess the effect of oral probiotic containing the Streptococcus salivarius M18 strain on gingival inflammation, bleeding on probing, and oral biofilm. Sixty-one consenting participants aged between 18 and 25 with gingivitis were recruited in this double-blind, parallel-group study and randomly divided into the probiotic group (n = 31) and the placebo group (n = 30). Fifty-seven participants completed the entire study protocol, 27 in the probiotic group and 30 in the placebo group. The outcomes were assessed after 4 weeks of intervention and 4 weeks of follow-up. There was a significant decrease in the Gingival Index, with the effect size of 0.58 [95%CI 0.05–1.10], and Turesky modification of the Quigley and Hein Plaque Index, with the effect size of 0.55 [95%CI: 0.02–1.07], in the probiotic group after the intervention. However, after a 4-week follow-up, the only significant treatment outcome was improved gingival condition according to the Gingival Index. The Gingival Bleeding Index also decreased significantly in the probiotic group after the intervention period; after the follow-up, this parameter did not differ significantly in both groups from the baseline values. In the placebo group, there were no significant improvements in the assessed parameters throughout this study. No serious side effects were registered. Within the limitations of this study, we conclude that the use of oral probiotic containing the Streptococcus salivarius M18 strain resulted in a significant improvement in gingival condition and oral hygiene level in young adults with gingivitis. Trial registration NCT05727436. Funding: none.

This cross-sectional survey assessed the knowledge of and the attitude towards probiotics of dental students and academics at Sechenov University, Moscow, Russia. Our questionnaire consisted of 15 questions divided into 3 sections: respondents’ sociodemographic data, knowledge on probiotics, and attitude towards probiotics. The data were analyzed using the Mann–Whitney U test, Fisher’s exact test, and Spearman’s rank correlation coefficient. Out of the 658 questionnaires distributed, a total of 239 questionnaires were completed by the undergraduates, yielding a response rate of 39.6%, and 54 by the teaching staff (response rate = 100%). Most students (53.6%) and teachers (55.5%) had a fair knowledge of probiotics (p = 0.3135). A vast majority of dental students (97.9%) and all teachers had a positive attitude towards probiotics, with higher mean scores among academics (p < 0.001). A positive weak correlation was found between knowledge and attitude (Spearman r = 0.17, p = 0.0027). The results obtained reveal the need for more evidence-based educational trainings for university teachers and a course on probiotics to be included in the curriculum for dental students.

S. salivarius M18 administration has been proven to provide positive effects on periodontal health; however, there is still no consensus on the optimum duration of probiotic administration. This study aimed to evaluate the effect of three months of probiotic supplementation on bleeding on probing, signs of gingival inflammation, and dental biofilm. Sixty-two eligible individuals with gingivitis were enrolled in this placebo-controlled, double-blind trial and randomly allocated to the M18 or control groups. Primary outcomes were changes in gingival condition (gingival index, GI; gingival bleeding index, GBI) after 1, 2, and 3 months of lozenges administration and after a one-month washout. Secondary outcomes included changes in the Quigley–Hein plaque index (modified by Turesky et al.) after 1, 2, and 3 months of lozenges administration and after a washout. In total, 60 individuals completed the study (31 and 29 in the M18 group and the control group, respectively). No severe adverse events were reported. Probiotic supplementation resulted in a significant decrease in gingival bleeding at 1 month (effect size 1.09 [CI95%: 0.55–1.63]), 2 months (effect size 0.78 [CI95%: 0.26–1.30]), and 3 months (effect size 0.67 [CI95%: 0.15–1.18]) and a significant reduction in dental plaque accumulation at 2 months (effect size 0.63 [CI95%: 0.12–1.14]) and 3 months (effect size 0.55 [CI95%: 0.03–1.05]). A three-month supplementation with the probiotic resulted in a significant reduction in gingival bleeding and biofilm accumulation; however, a long-lasting effect is not expected, indicating the need for probiotic intake on a long-term basis.

Background. The majority of dental diseases develop as a result of an imbalance in the oral microflora. One of the promising approaches for its prevention is to re-balance the microflora by administering pre- and probiotics - medications that promote the replacement of opportunistic microorganisms with commensals. Objective. Assessment of the impact of a 3-month oral probiotic (Streptococcus salivarius K12 strain) supplementation on salivary secretory immunoglobulin a (sIgA) concentration, salivation rate, and oral hygiene index values. Materials and methods. Fifty-nine subjects participated in this double-blind, placebo-controlled study. Twenty-eight participants were randomly assigned to the probiotic group and 31 to the placebo group. For 12 weeks, participants took 1 lozenge per day. This was followed by a 4-week washout period. Salivary sIgA concentration and salivation rate were considered primary outcomes, and the Turesky index was considered secondary outcome. None of the participants reported any adverse events. Results. A total of 59 participants completed the study protocol. We observed an increase in salivary sIgA concentration, salivary flow rate and a decrease in plaque formation rate in the probiotic group. Mean sIgA values at baseline and after 12 weeks of probiotic/placebo administration were 206.97±104.86 and 248.55±103.68 in the probiotic group and 206.54±87.15 and 192.09±94.79 in the placebo group, respectively. The salivation rate increased statistically significantly after 12 weeks of probiotic supplementation, but the result was not stable by the end of the washout period. A statistically significant decrease in the rate of plaque formation was observed after 12 weeks of probiotic supplementation, but the result was not stable after 4 weeks of the washout period. Conclusion: probiotic supplementation for 3 months increases the concentration of sIgA in saliva, salivary flow rate, and decreases the rate of plaque formation.