Reduction of Streptococcus mutans by probiotic milk: a multicenter randomized controlled trial

Effect of Probiotic Supplements on the Oral Microbiota-A Narrative Review

Data from systematic reviews and meta-analyses show that probiotics positively impact clinical parameters of oral diseases such as gingivitis, dental caries, and periodontitis. However, the working mechanism of probiotics is not fully understood, but is hypothesized to be mediated by direct and indirect interactions with the oral microbiota and the human host. In the present narrative review, we focused on the microbiological effect of probiotic supplements based on data retrieved from randomized clinical trials (RCTs). In addition, we assessed to what extent contemporary molecular methods have been employed in clinical trials in the field of oral probiotics. Multiple RCTs have been performed studying the potential effect of probiotics on gingivitis, dental caries, and periodontitis, as evaluated by microbial endpoints. In general, results are conflicting, with some studies reporting a positive effect, whereas others are not able to record any effect. Major differences in terms of study designs and sample size, as well as delivery route, frequency, and duration of probiotic consumption, hamper comparison across studies. In addition, most RCTs have been performed with a limited sample size using relatively simple methods for microbial identification, such as culturing, qPCR, and DNA-DNA checkerboard, while high-throughput methods such as 16S sequencing have only been employed in a few studies. Currently, state-of-the-art molecular methods such as metagenomics, metatranscriptomics, and metaproteomics have not yet been used in RCTs in the field of probiotics. The present narrative review revealed that the effect of probiotic supplements on the oral microbiota remains largely uncovered. One important reason is that most RCTs are performed without studying the microbiological effect. To facilitate future systematic reviews and meta-analyses, an internationally agreed core outcome set for the reporting of microbial endpoints in clinical trials would be desirable. Such a standardized collection of outcomes would most likely improve the quality of probiotic research in the oral context.

Anti-caries Streptococcus spp.: A potential preventive tool for special needs patients

INTRODUCTION

Probiotics are living microorganisms that act on the host-microbiome interface to restore the microbiota's physiological homeostasis. Numerous probiotics have been marketed with inhibitory activity against Streptococcus mutans and consequently with a potential anti-caries effect, mainly of the genera Lactobacillus and Bifidobacterium, whose main disadvantage is their limited ability to settle in the oral cavity.

METHODS

This narrative review describes the main Streptococcus spp. with probiotic anti-Streptococcus mutans activity, whose substantivity is greater than that of Lactobacillus spp. and consequently with anti-caries potentiality. We performed a literature review in the PubMed, Science Direct and Google Scholar databases of articles published in English (without time restriction) related to caries and probiotics.

RESULTS

The potential identified anti-caries probiotics included Streptococcus spp. A12, Streptococcus oralis (AJ3), Streptococcus oligofermentans, Streptococcus salivarius (K12, M18, JH, LAB813, 24SMB), Streptococcus spp. with arginolytic activity (S. sanguinis, S. gordonii, S. ratti, S. parasanguinis, S. intermedius, S. australis, and S. cristatus), Streptococcus rattus (JH145), Streptococcus dentisani and Streptococcus downii.

CONCLUSIONS

The possibility of using these Streptococcus spp. as probiotics that inhibit the growth of dental plaque and the development of carious lesions represents a potential tool of particular interest for individuals with physical or intellectual disabilities that impede the routine and effective application of mechanical dental plaque removal techniques.

Unlocking the potential of probiotic administration in caries management: a systematic review

BACKGROUND

The use of prebiotics and/or probiotic bacteria with the potential to modulate the oral ecosystem may play an important role in the prevention and management of dental caries. To assess the evidence of the potential of pre/probiotics both in the prevention and treatment of dental caries, we focused on the PICO question "In individuals with caries, after probiotic administration, is there an improvement in outcomes directly related to caries risk and development?".

METHODS

An extensive systematic search was conducted in electronic databases PubMed, Web of Science, Scopus and Cochrane, to identify articles with relevant data. This systematic review included trials performed in Humans; published in English; including the observation of patients with caries, with clear indication of the probiotic used and measuring the outcomes directly involved with the cariogenic process, including the quantification of bacteria with cariogenic potential. To evaluate the methodological quality of the studies, the critical assessment tool from the Joanna Briggs Institute was used.

RESULTS

Eight hundred and fifty articles, potentially relevant, were identified. Following PRISMA guidelines 14 articles were included in this systematic review. Outcomes such as reduction of cariogenic microorganism counts, salivary pH, buffer capacity, and caries activity were assessed. The probiotic most often referred with beneficial results in dental caries outcomes is Lacticaseibacillus rhamnosus. Regarding the most used administration vehicle, in studies with positive effects on the caries management, probiotic supplemented milk could be considered the best administration vehicle.

CONCLUSIONS

Evidence suggests a beneficial effect of probiotic supplemented milk (Lacticaseibacillus rhamnosus) as an adjuvant for caries prevention and management. However, comparable evidence is scarce and better designed and comparable studies are needed.

Anti-cancer Properties of Potential Probiotics and Their Cell-free Supernatants for the Prevention of Colorectal Cancer: an In Vitro Study

This study aimed to characterize the anti-cancer properties of potential probiotics (Lacticaseibacillus paracasei SD1, Lacticaseibacillus rhamnosus SD4, Lacticaseibacillus rhamnosus SD11, and Lacticaseibacillus rhamnosus GG) and their cell-free supernatants (CFS) for the prevention of colorectal cancer (CRC), which including anti-bacterial and anti-inflammation activities against pathogens associated with CRC (Fusobacterium nucleatum, Porphyromonas gingivalis, ETEC, and Salmonella enterica). The expression of human β-defensin (2-4) and IL-10 after being stimulated with probiotics was also examined. In addition, anti-cancer activity of CFS and probiotic growth under intestinal conditions were determined. An in vitro study was conducted in the Caco-2 and HIEC-6 cells. Results showed that probiotic cells and their CFS displayed different antibacterial activity, and L. rhamnosus SD11 showed the strongest inhibition of the growth of pathogens. Additionally, both probiotic cell walls and their CFS suppressed pro-inflammatory cytokines after being stimulated with pathogens in Caco-2 and HIEC-6 cells. L. paracasei SD1 and L. rhamnosus SD11 showed significantly higher suppression levels than others and also both strains can stimulate highly expression of hBD (2-4) and IL-10. The CFS of L. paracasei SD1 and L. rhamnosus SD11 inhibited significantly high growth of Caco-2 cells but not much in HIEC-6 cells. Furthermore, all probiotics adhered to Caco-2 and HIEC-6 cells, and L. rhamnosus SD4 showed the highest adhesion to both cells. They could survive more than 70% in intestinal conditions. In conclusion, results indicate that potential probiotics tested exhibited various anti-cancer properties, which may be good candidates used as biotherapy for the prevention or to delay the progression of CRC.

Association of polymicrobial interactions with dental caries development and prevention

Dental caries is a common oral disease. In many cases, disruption of the ecological balance of the oral cavity can result in the occurrence of dental caries. There are many cariogenic microbiota and factors, and their identification allows us to take corresponding prevention and control measures. With the development of microbiology, the caries-causing bacteria have evolved from the traditional single Streptococcus mutans to the discovery of oral symbiotic bacteria. Thus it is necessary to systematically organized the association of polymicrobial interactions with dental caries development. In terms of ecology, caries occurs due to an ecological imbalance of the microbiota, caused by the growth and reproduction of cariogenic microbiota due to external factors or the disruption of homeostasis by one's own factors. To reduce the occurrence of dental caries effectively, and considering the latest scientific viewpoints, caries may be viewed from the perspective of ecology, and preventive measures can be taken; hence, this article systematically summarizes the prevention and treatment of dental caries from the aspects of ecological perspectives, in particular the ecological biofilm formation, bacterial quorum sensing, the main cariogenic microbiota, and preventive measures.

Knowledge and Attitude towards Probiotics among Dental Students and Teachers: A Cross-Sectional Survey

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.

Characterization of Short Chain Fatty Acids Produced by Selected Potential Probiotic Lactobacillus Strains

Short-chain fatty acids (SCFAs), particularly butyrate, have received considerable attention with regard to their anti-cancer efficacy in delaying or preventing colorectal cancer. Several studies have reported that certain probiotic strains could produce SCFAs; however, different strains yielded different amounts of SCFAs. This study explored the ability to produce SCFAs of the following probiotic strains: Lacticaseibacillus paracasei SD1, Lacticaseibacillus rhamnosus SD4, Lacticaseibacillus rhamnosus SD11, and Lacticaseibacillus rhamnosus GG. L. paracasei SD1 and L. rhamnosus SD11 exhibited high butyrate production, particularly when the strains were combined. The functions of the SCFAs were further characterized; the SCFAs exerted a positive anti-cancer effect in the colon via various actions, including inhibiting the growth of the pathogens related to colon cancer, such as Fusobacterium nucleatum and Porphyromonas gingivalis; suppressing the growth of cancer cells; and stimulating the production of the anti-inflammatory cytokine IL-10 and antimicrobial peptides, especially human β-defensin-2. In addition, the SCFAs suppressed pathogen-stimulated pro-inflammatory cytokines, especially IL-8. The results of this study indicated that selected probiotic strains, particularly L. paracasei SD1 in combination with L. rhamnosus SD11, may serve as good natural sources of bio-butyrate, which may be used as biotherapy for preventing or delaying the progression of colon cancer.

Efficacy of probiotics against dental caries in children: a systematic review and meta-analysis

Dental caries causes serious consequences and the financial burden of society especially in children with high morbidity rate. Here we carried out a meta-analysis to systematically evaluate the efficacy of probiotics against dental caries in children. Forty-three RCTs were eligible for this meta-analysis after searching the PubMed, Cochrane and Web of Science from the inception through October 2021. Pooled estimates demonstrated that treatment with probiotics significantly reduced noncavitated (dicdas2-6mft) (SMD = -0.18, 95% CI: -0.3 to -0.06, p = 0.002) and cavitated (dicdas5-6mft) carious lesions in children (SMD = -0.32, 95% CI: -0.5 to 0.14, p = 0.0004). Probiotics also reduced prevalence of noncavitated (dicdas2-6mft) carious lesions (RR = 0.8, 95% CI: 0.67 to-0.97, p = 0.02). Salivary Streptococcus mutans was declined after intervention (SMD = -1.17, 95% CI: -1.85 to -0.5, p = 0.0007), while Lactobacillus counts were upregulated (SMD = 1.19, 95% CI: 0.46-1.92, p = 0.001). However, no significant effects in total bacteria counts and salivary pH were observed. Our findings suggest that probiotics especially Lactobacillus could be a promising therapeutic strategy for clinical applications in children dental caries.

The Effect of Oral Probiotics (Streptococcus Salivarius k12) on the Salivary Level of Secretory Immunoglobulin A, Salivation Rate, and Oral Biofilm: A Pilot Randomized Clinical Trial

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.

Comparison of Antibacterial Effect of Probiotic Yogurt and Xylitol-Containing Chewing Gum in Geriatric Patients: A Randomized Controlled Clinical Trial

Objectives

To evaluate the effect of probiotic bacteria in yogurt on Streptococcus mutans (MS) count, plaque adherence and salivary pH compared to xylitol-containing chewing gum in geriatric patients.

Materials and methods

Total number of 96 high caries risk geriatric patients were randomized into two equal groups (n=48). Group 1 (intervention group) received probiotic yogurt (Activia, Danone) once per day, and group 2 (control group) received xylitol chewing gum (Trident original) three times per day. The primary outcome was salivary Streptococcus mutans count and secondary outcomes were interdental plaque Streptococcus mutans count, salivary pH and bacterial adherence.

Results

For Streptococcus mutans count in saliva and plaque, a statistically significant reduction in the level of MS over all the examined follow up periods of the study in probiotic yogurt group as well as xylitol gum group was found. An intergroup comparison for salivary MS count showed statistically significant difference between the two materials in a two week and a three month period of time and there was no statistically significant difference between both materials at one month time period. Salivary pH results showed statistically significant increase in pH in both groups along the follow-up periods. Bacterial adherence results showed statistically significant reduction in both groups.

Conclusions

Probiotic yogurt is an effective antibacterial agent against salivary and plaque bacteria in geriatric patients.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2020 professional literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to this work to cover this broad topic. Specific subject areas addressed include prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders (TMDs); sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence day-to-day dental treatment decisions with a keen eye on future trends in the profession. With the tremendous volume of dentistry and related literature being published today, this review cannot possibly be comprehensive. The purpose is to update interested readers and provide important resource material for those interested in pursuing greater detail. It remains our intent to assist colleagues in navigating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the dental patients they encounter.

Probiotics, Prebiotics, Synbiotics and Dental Caries. New Perspectives, Suggestions, and Patient Coaching Approach for a Cavity-Free Mouth

Probiotic therapy forms a new strategy for dental caries prevention. Probiotic microorganisms possess the ability to displace cariogenic microorganisms and colonize the oral cavity. They can produce various antimicrobial substances such as bacteriocins, bacteriocin-like peptides, lactic acid, and hydrogen peroxide. Dairy products may be ideal for probiotic administration in dental patients. Many other means have been proposed, primarily for those allergic to dairy components, such as capsules, liquid form, tablets, drops, lozenges, sweetened cakes, and ice creams. The last two forms can be used in a coaching approach for children and elderly patients who find it difficult to avoid sugary beverages in their daily routine and benefit from the suggestion of easy, cheap, and common forms of delicacies. In caries prevention, the concept of the effector strain is already considered an integral part of the contemporary caries cure or prevention strategy in adults. Adults, though, seem not to be favored as much as children at early ages by using probiotics primarily due to their oral microbiome’s stability. In this non-systematic review we describe the modes of action of probiotics, their use in the cariology field, their clinical potential, and propose options to prevent caries through a patient coaching approach for the daily dental practice.

Efficacy of Probiotic Milk for Caries Regression in Preschool Children: A Multicenter Randomized Controlled Trial

This multicenter double-blind randomized controlled trial aimed to determine the efficacy of daily or triweekly consumption of reconstituted milk powder, containing <i>Lactobacillus paracasei</i>SD1, in preschool children for caries prevention. A 6-month intervention was conducted in 487 children (aged 37.6 ± 9.2 months) with ≤4 decayed teeth from 8 childcare centers. Using stratified block randomization, participants were randomly allocated into 3 groups, comprising: (1) daily probiotic, receiving probiotic milk once daily, (2) triweekly probiotic, randomly receiving probiotic milk 3 days a week and the placebo milk for the remaining 4 days, and (3) placebo, receiving milk without probiotics. Each tooth surface was assessed for caries status using the modified Nyvad criteria at baseline (T0), 6 (T6) and 12 (T12) months after T0. Study outcomes were caries transition, including caries progression and regression during the T0–T6, T6–T12 and T0–T12 periods. Negative binomial regression with a generalized linear model was used to estimate the caries outcomes, which were reported as incidence rate ratios (IRRs) and 95% confidence intervals (CIs). At baseline, caries prevalence and mean decayed surfaces were 81.9% and 7.29 ± 7.60, respectively. Three groups were balanced at baseline with an overall dropout rate of 25.2%. After adjusting for age, sex, and the number of noncavitated and cavitated caries at baseline, a decreased caries risk during T0–T6 was shown in both the daily and triweekly probiotic groups (adjusted IRR 0.83, 95% CI 0.72–0.96 in both groups) and during T0–T12 (adjusted IRR 0.84, 95% CI 0.76–0.94, and adjusted IRR 0.86, 95% CI 0.76–0.96, respectively) compared to the placebo group. In contrast, significantly increased regressive surfaces were demonstrated during T0–T6 by adjusted IRR 1.76 (95% CI 1.25–2.48) and 2.01 (95% CI 1.42–2.85) and during T0–T12 by adjusted IRR 1.98 (95% CI 1.50–2.61) and 1.92 (95% CI 1.45–2.55) for the daily and triweekly groups, respectively. In conclusion, probiotic milk consumption either daily or triweekly can modestly prevent new caries, but considerably reverse carious lesions, suggesting that a daily or triweekly dose interval is sufficient to reverse carious lesions.

Significant elevation of salivary human neutrophil peptides 1-3 levels by probiotic milk in preschool children with severe early childhood caries: a randomized controlled trial

OBJECTIVES

To determine salivary human neutrophil peptides 1-3 (HNP1-3) levels in caries-free preschool children and in those with early childhood caries (ECC) or severe-ECC, in a daily probiotic group, receiving reconstituted milk with the probiotic Lactobacillus paracasei SD1 once daily; a triweekly probiotic group, receiving the probiotic milk 3 days a week; and a placebo group.

MATERIALS AND METHODS

Oral examination and unstimulated whole saliva collection were conducted in 354 children at baseline, 6 months after intervention (T6), and after probiotic discontinuation (T12). Of the 354, adequate volume of saliva samples from 268 children were simultaneously analyzed for Streptococcus mutans and total lactobacilli levels using qPCR and for HNP1-3 levels using ELISA.

RESULTS

In the severe-ECC status, significant increases in the median HNP1-3 levels at T12 were found in both daily and triweekly probiotic groups (p < 0.001). The median S. mutans levels in the daily group were significantly decreased at T6 and T12 (p < 0.01), whereas the median total lactobacilli levels were significantly increased at T6 (p < 0.001). Significantly inverse correlations between altered HNP1-3 and S. mutans levels and significant decreases in caries progression were found in both probiotic groups (p < 0.05).

CONCLUSIONS

In the severe-ECC status, daily or triweekly consumption of L. paracasei SD1 significantly enhanced salivary HNP1-3 levels, but reduced S. mutans levels, possibly resulting in reduction of caries progression.

CLINICAL RELEVANCE

Significant enhancement of salivary HNP1-3 levels by probiotic consumption is associated with reduction in S. mutans levels, consistent with diminished caries progression in children with severe-ECC.

Role of Probiotics in Oral Health Maintenance Among Patients Undergoing Fixed Orthodontic Therapy: a Systematic Review of Randomized Controlled Clinical Trials

The aim was to assess the role of probiotics in oral health maintenance among patients undergoing fixed orthodontic therapy (OT). An unrestricted search of indexed databases was performed until April 2020 using the following Mesh-terms: (1) probiotic and (2) orthodontic. Randomized controlled clinical trials (RCTs) evaluating the influence of probiotic therapy (PT) towards oral health maintenance/improvement in patients undergoing fixed OT were included. Data screening, selection, and extraction were performed; and the risk of bias was assessed using the Cochrane Collaboration's tool. All evaluations were performed by 2 independent researchers; and disagreements were resolved via discussion. Nine RCTs were included. Eight studies reported that PT improves oral health in patients undergoing fixed OT. Seven studies showed that PT reduces the counts of oral pathogenic bacteria in the oral biofilm and/or saliva. One study reported that PT reduces halitosis in patients undergoing fixed OT. One study found that PT reduces the scores of plaque index (PI) and gingival index (GI); and one study reported that PT has no significant influence on PI and GI in patients undergoing fixed OT. One study reported that PT does not prevent the formation of white spot lesions during fixed OT. Three and 6 studies had a moderate and low risk of bias, respectively. A power analysis was performed in 4 studies. In conclusion, probiotics exhibit antimicrobial activity against oral pathogenic bacteria; however, due to the limitations of the studies assessed, further well-designed RCTs are needed.