The use of probiotic strains in caries prevention: a systematic review

Probiotics for maintaining oral health during fixed orthodontic treatment: A systematic review and meta-analysis

INTRODUCTION

To systematically review the effect of probiotics on oral health during treatment with fixed orthodontic appliances.

METHODS

PubMed, Embase and the Cochrane Library were searched up to August 2022 using broad MeSH terms and keywords. Randomized clinical trials comparing a probiotic with a control/no treatment; at least 10 patients/group undergoing fixed orthodontic therapy; and reporting at least one oral health-related parameter were included.

RESULTS

The most reported parameters in the 14 included studies were the microbiological counts of mutans streptococci and lactobacilli, microorganisms associated with white spot lesions (WSL). A meta-analysis of these showed a positive effect of probiotics on mutans streptococci. Probiotic treatment led to significantly less patients with high counts and significantly more with low counts of these bacteria. An effect on the lactobacilli counts was not seen. However, the sole clinical study investigating WSL could not demonstrate a clinical effect of probiotics on these lesions. Additionally, one study reported encouraging results of probiotics on bad breath and one on the occurrence of traumatic oral lesions. One study found reduced counts of Porphyromonas gingivalis in the probiotic group. The clinical results of probiotics on plaque index were ambiguous: one study reported that probiotics reduce the plaque and gingival index, and two that probiotics had no significant influence on plaque index.

CONCLUSION

Probiotics are a promising option to lower mutans streptococci counts in patients undergoing fixed orthodontic therapy. However, due to the heterogeneity of the studies, it is not possible to draw conclusions about one specific probiotic.

Chemical Characterization and Effect of a Lactobacilli-Postbiotic on Streptococcus mutans Biofilm In Vitro

Postbiotic is the term used to define the soluble factors, metabolic products, or byproducts released by live probiotic bacteria or after its lysis. The objective of this study was to carry out the chemical characterization of the postbiotic of Lacticaseibacillus rhamnosus LR-32 and to evaluate its in vitro effect on the development of the Streptococcus mutans biofilm. After the cultivation of the probiotic strain, the postbiotic was extracted by centrifuging the culture and filtering the supernatant. This postbiotic was characterized by using gas chromatography coupled with mass spectrometry (GC-MS), and then it was used to determine the growth inhibition of S. mutans in its planktonic form; additionally, its effects on the following parameters in 48 h biofilm were evaluated: viable bacteria, dry weight, and gene expression of glucosyltransferases and VicR gene. The control group consisted of the biofilm without any treatment. A paired t-test was performed for statistical analysis, with the p-value set at 5%. Seventeen compounds of various chemical classes were identified in the postbiotic, including sugars, amino acids, vitamins, and acids. The treatment with the postbiotic led to an inhibition of the growth of S. mutans in its planktonic form, as well as a decrease in the number of viable bacteria, reduction in dry weight, and a negative regulation of the gene expression of gtfB, gtfC, gtfD, and vicR in its biofilm state, compared with the nontreated group (p < 0.05). The postbiotic of L. rhamnosus impaired the development of S. mutans biofilm.

Manipulating the diseased oral microbiome: the power of probiotics and prebiotics

Dental caries and periodontal disease are amongst the most prevalent global disorders. Their aetiology is rooted in microbial activity within the oral cavity, through the generation of detrimental metabolites and the instigation of potentially adverse host immune responses. Due to the increasing threat of antimicrobial resistance, alternative approaches to readdress the balance are necessary. Advances in sequencing technologies have established relationships between disease and oral dysbiosis, and commercial enterprises seek to identify probiotic and prebiotic formulations to tackle preventable oral disorders through colonisation with, or promotion of, beneficial microbes. It is the metabolic characteristics and immunomodulatory capabilities of resident species which underlie health status. Research emphasis on the metabolic environment of the oral cavity has elucidated relationships between commensal and pathogenic organisms, for example, the sequential metabolism of fermentable carbohydrates deemed central to acid production in cariogenicity. Therefore, a focus on the preservation of an ecological homeostasis in the oral environment may be the most appropriate approach to health conservation. In this review we discuss an ecological approach to the maintenance of a healthy oral environment and debate the potential use of probiotic and prebiotic supplementation, specifically targeted at sustaining oral niches to preserve the delicately balanced microbiome.

Efficacy and Safety of Probiotics for Dental Caries in Preschool Children: A Systematic Review and Meta-analysis

Background

Early childhood caries is one of the most serious and high-priced oral health conditions among young children. With advancing dental sciences, the focus of dental caries treatment is shifted from restorative procedures to preventive measures, and a modality grabbing attention is probiotics. Probiotics exert their effects in many ways as chemical inhibition of pathogenic bacteria and stimulation of the immune response through the production of immunoglobulin A and many more.

Objective

This systematic review aims to explore the efficacy and safety of probiotics in dental caries in preschool children.

Methodology

The study was registered in the PROSPERO International Prospective Register of Systematic Reviews (registration number: CRD42020159058). The search was done for randomized control trials in electronic databases such as Cochrane, PubMed, ClinicalTrials.gov, Medline, and Embase. It has further included manual searches of journals, conference abstracts, and books. Three reviewers done the selection of the study as per the criteria and also did the risk of bias assessment independently and wherever required, a fourth reviewer resolved the discrepancy in case of disagreement.

Results

The nine randomized control trials were included in the study, and the pooled analysis revealed probiotics as an effective intervention in preschool children with dental caries.

Conclusion

The results about the efficacy of probiotics in the prevention of dental caries are very encouraging, though the level of evidence is still inadequate.

Effects of probiotic yogurt, casein phosphopeptide-amorphous calcium phosphate, and xylitol chewing gums on the salivary count of Streptococcus mutans: A single-blinded randomized controlled clinical trial

Background

Dental caries is a preventable multifactorial disease, with Streptococcus mutans being suggested to be its primary pathogen. Our study aim was to compare the effects of three different low-cost and easy-to-use regimens with that of the gold standard (chlorhexidine [CHX] mouthwash) on the count of salivary S. mutans in dental students over 30 days.

Materials and Methods

In this single-blinded parallel randomized controlled clinical trial, a total of 120 dental students were included and randomly allocated into four intervention groups: (1) CHX mouthwash (control(, (2) probiotic yogurt, (3) casein phosphopeptide-amorphous calcium phosphate chewing gum, and (4) xylitol chewing gum. Salivary S. mutans counts were evaluated at baseline, 15 days, and 30 days after initiation of the study and compared at different times and among different groups using the repeated measures analysis of variance design analysis and least significant difference test with SPSS software version 20. The level of significance was determined to be 0.05.

Results

The microorganism count variable at baseline, first, and second follow-ups was significantly different for all groups except the probiotic yogurt group (P = 0.340). S. mutans count was significantly different when comparing the first follow-up and baseline values in the CHX and xylitol gum groups (P = 0.027, P = 0.037). When comparing the second follow-up with baseline values, a significant difference was observed in the xylitol gum group (P = 0.003).

Conclusion

Xylitol chewing gum seems to be a viable alternative to the gold standard (CHX mouthwash) in reducing the salivary count of S. mutans.

Inhibitory effects of Bacillus velezensis ID-A01 supernatant against Streptococcus mutans

BACKGROUND

Dental caries is a chronic oral disease caused by microbial infections, which result in erosion of the dental enamel and cause irreversible damage. Therefore, proper disease management techniques and the creation of an environment that prevents intraoral growth and biofilm formation of Streptococcus mutans in the early stages, are crucial to prevent the potential progression of dental plaque to disease. Here, we aimed to investigate antimicrobial and antibiofilm effects of the Bacillus velezensis ID-A01 supernatant (ID23029) against S. mutans, and its inhibitory effects on acidogenesis.

RESULTS

A killing kinetics assay showed a peak lethality percentage of 94.5% after 6 h of exposure to ID23029. In sucrose-exposed conditions, ID23029 inhibited lactic acid formation, preventing the pH from falling below the threshold for enamel demineralization, and inhibited up to 96.6% of biofilm formation. This effect was maintained in the presence of lysozyme. Furthermore, ID23029 retained up to 92% lethality, even at an intraoral concentration at which lysozyme is ineffective against S. mutans.

CONCLUSIONS

This study demonstrates the potential of the B. velezensis ID-A01 supernatant for the prevention and treatment of dental caries. Its eventual use in dental practice is encouraged, although further studies are required to confirm its beneficial effects.

Effect of Motiflor AS probiotic for oral health on cell viability in human gingival fibroblasts and human dental pulp stem cells

Objectives

In this study, it was aimed to investigate the possible effects of oral chewable probiotic tablets (PTs) produced to directly support the oral flora on the proliferation of human dental pulp stem cells (DPSCs) and human gingival fibroblast cells (HGFCs).

Materials and Methods

For analysis in this study, "Motiflor AS," a PT that dissolves in the mouth, containing 13.5mg Lactobacillus helveticus Rosell-52, L. rhamnosus Rosell-11, L. halivarus HA-118, and Bifidobacterium longum Rosell-175 was used. Cell survival and proliferation were analyzed by methyl-thiazole-diphenyl-tetrazolium (MTT) test and real-time cell analysis method (xCELLigence RTCA-DP) after 24-, 48-, and 72-h incubation periods.

Results

According to the data obtained with RTCA-DP software, there was a significant increase in the proliferation of human dental pulp stem cells (HDPSCs) and HGFCs in the 72-h incubation after PT application compared to the 24-h and 48-h incubations (P < 0.0001). After the MTT test, for HDPSCs, the cell proliferation rate was 62.8% and 85.6% in 24- and 48-h incubation, respectively, while HDPSCs cell proliferation rate in 72-h incubation was 135.2% (P < 0.0001). For HGFCs, the cell proliferation rate was 73% and 120.4% in 24- and 48-h incubation, respectively, while HDPSCs cell proliferation rate in 72-h incubation was 139.8% (P < 0.0001). When the results of the two tests applied were evaluated together, the results showed compatibility.

Conclusions

Based on the results, it has been concluded that PT will be useful for maintaining oral health and for dental and gingival patients who will/have undergone dental treatment. It should be keep in mind that protecting our oral and dental health is very important in terms of protecting our general health.

YouTube Videos on Nutrition and Dental Caries: Content Analysis

BACKGROUND

Dental caries is the most common health condition worldwide, and nutrition and dental caries have a strong interconnected relationship. Foods and eating behaviors can be both harmful (eg, sugar) and healthful (eg, meal spacing) for dental caries. YouTube is a popular source for the public to access information. To date, there is no information available on the nutrition and dental caries content of easily accessible YouTube videos.

OBJECTIVE

This study aimed to analyze the content of YouTube videos on nutrition and dental caries.

METHODS

In total, 6 YouTube searches were conducted using keywords related to nutrition and dental caries. The first 20 videos were selected from each search. Video content was scored (17 possible points; higher scores were associated with more topics covered) by 2 individuals based on the inclusion of information regarding various foods and eating behaviors that impact dental caries risk. For each video, information on video characteristics (ie, view count, length, number of likes, number of dislikes, and video age) was captured. Videos were divided into 2 groups by view rate (views/day); differences in scores and types of nutrition messages between groups were determined using nonparametric statistics.

RESULTS

In total, 42 videos were included. Most videos were posted by or featured oral health professionals (24/42, 57%). The mean score was 4.9 (SD 3.4) out of 17 points. Videos with >30 views/day (high view rate; 20/42, 48% videos) had a trend toward a lower score (mean 4.0, SD 3.7) than videos with ≤30 views/day (low view rate; 22/42, 52%; mean 5.8, SD 3.0; P=.06), but this result was not statistically significant. Sugar was the most consistently mentioned topic in the videos (31/42, 74%). No other topics were mentioned in more than 50% of videos. Low-view rate videos were more likely to mention messaging on acidic foods and beverages (P=.04), water (P=.09), and frequency of sugar intake (P=.047) than high-view rate videos.

CONCLUSIONS

Overall, the analyzed videos had low scores for nutritional and dental caries content. This study provides insights into the messaging available on nutrition and dental caries for the public and guidance on how to make improvements in this area.

Laboratory evaluation of anti-plaque and remineralization efficacy of sugarless probiotic jelly candy supplemented with natural nano prebiotic additive

We evaluated the anti-cariogenic effect of an experimental synbiotic compound containing probiotic Lacticaseibacillus rhamnosus (NRRL B-442)-based jelly candy supplemented with natural prebiotic grape seed extract (GSE) in a nanoemulsion formula on the colonization and establishment of Streptococcus mutans (ATCC 25175) and Actinomyces viscosus (ATTCC 19246) biofilms through counting colony forming units, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). We were then analysing the remineralizing effect of synbiotic jelly candy on human enamel surface lesions using Vickers microhardness testers, atomic force microscopy (AFM), SEM, energy-dispersive X-ray spectroscopy (EDAX), and confocal laser scanning microscopy (CLSM) at three stages (sound, after demineralization, and after pH cycling). We found after 21 days of treatment of the pH-cycled enamel discs with jelly candy for 10 min twice daily, a 68% decrease in S. mutans colony formation, reducing biofilm development, trapping S. mutans visualized in jelly candy under SEM examination, and significantly altering the morphological structure of these bacteria under TEM analysis. For remineralization measurements, statistically significant differences in microhardness integrated mineral loss, and lesion depth through CLSM between demineralization and treatment stages. These findings provide an effective anti-cariogenic synbiotic compound of grape seed extract and probiotic jelly candy with potential remineralizing activity.

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.

Evaluation of Probiotic Effects of Lactobacilli on Mutans Streptococci: An In Vitro Study

AIM

The aim of the present study is to evaluate the probiotic effect of Lactobacillus acidophilus and Lactobacillus rhamnosus on clinical isolates of Mutans Streptococci (MS) and antibiotic susceptibility of these strains to commonly used antibiotics in dentistry.

MATERIALS AND METHODS

Plaque samples from permanent first molars were collected and transferred aseptically onto Mitis-Salivarius agar and incubated at 37°C for 24 hours in the presence of 5-10% CO₂. Mutans streptococci colonies were identified biochemically using Hi-Strep identification kit. The inhibitory activity of the clinical strains of MS on Lactobacilli was investigated using agar-overlay interference technique. Positive inhibition was appreciated as a clear zone around the Lactobacilli. Disk diffusion assay was done as described by CLSI M100-S25 for antibiotic susceptibility. The zone of growth inhibition caused by Lactobacilli and antibiotics on MS clinical strains was measured directly using a vernier caliper. Statistical analysis was done using independent t-test.

RESULTS

Mutans streptococci exhibited positive inhibition with both the probiotic strains and L. acidophilus showed more zones of inhibition than L. rhamnosus. Antibiotic susceptibility of clinical strains of MS showed sensitivity to penicillin and vancomycin, however, tetracycline and erythromycin showed very few resistant strains. The highest zone of inhibition was shown by cephalothin followed by penicillin, tetracycline, ciprofloxacin, erythromycin, and vancomycin.

CONCLUSION

L. rhamnosus and L. acidophilus have strong inhibitory effects on clinical strains of MS. Lactobacillus acidophilus showed a higher zone of inhibition. All the clinical strains of MS were sensitive to penicillin and vancomycin. The highest zone of inhibition was shown by cephalothin.

CLINICAL SIGNIFICANCE

Dental caries remains silent epidemic and increasing antibiotic resistance is another major challenge that threatens the world. Newer methods such as whole-bacteria replacement therapy using probiotics for decreasing harmful oral pathogens and reducing the intake of antibiotics must be explored. More researches to promote use of probiotics should be initiated due to its possible preventive and health maintenance benefits providing an end to new cavities and antibiotic resistance.

Effect of Probiotic Lactobacillus plantarum on Streptococcus mutans and Candida albicans Clinical Isolates from Children with Early Childhood Caries

Probiotics interfere with pathogenic microorganisms or reinstate the natural microbiome. Streptococcus mutans and Candida albicans are well-known emerging pathogenic bacteria/fungi for dental caries. In this study, three probiotic Lactobacilli strains (Lactobacillus plantarum 8014, L. plantarum 14917, and Lactobacillus salivarius 11741) were tested on S. mutans and C. albicans clinical isolates using a multispecies biofilm model simulating clinical cariogenic conditions. The ten pairs of clinical isolates of S. mutans and C. albicans were obtained from children with severe early childhood caries. Our study findings show a remarkable inhibitory effect of L. plantarum 14917 on S. mutans and C. albicans clinical isolates, resulting in significantly reduced growth of S. mutans and C. albicans, a compromised biofilm structure with a significantly smaller microbial and extracellular matrix and a less virulent microcolony structure. FurTre, plantaricin, an antimicrobial peptide produced by L. plantarum, inhibited the growth of S. mutans and C. albicans. The mechanistic assessment indicated that L. plantarum 14917 had a positive inhibitory impact on the expression of S. mutans and C. albicans virulence genes and virulent structure, such as C. albicans hypha formation. Future utilization of L. plantarum 14917 and/or its antimicrobial peptide plantaricin could lead to a new paradigm shift in dental caries prevention.

A comprehensive review of the application of probiotics and postbiotics in oral health

Oral diseases are among the most common diseases around the world that people usually suffer from during their lifetime. Tooth decay is a multifactorial disease, and the composition of oral microbiota is a critical factor in its development. Also, Streptococcus mutans is considered the most important caries-causing species. It is expected that probiotics, as they adjust the intestinal microbiota and reduce the number of pathogenic bacteria in the human intestine, can exert their health-giving effects, especially the anti-pathogenic effect, in the oral cavity, which is part of the human gastrointestinal tract. Therefore, numerous in vitro and in vivo studies have been conducted on the role of probiotics in the prevention of tooth decay. In this review, while investigating the effect of different strains of probiotics Lactobacillus and Bifidobacteria on oral diseases, including dental caries, candida yeast infections, periodontal diseases, and halitosis, we have also discussed postbiotics as novel non-living biological compounds derived from probiotics.

Effect of a Short-Term Intervention with Lactobacillus salivarius Probiotic on Early Childhood Caries-An Open Label Randomized Controlled Trial

ECC is a significant therapeutic and social problem and a global burden on public health. The aim of this clinical trial was to test whether a 2-week daily consumption of chewing tablets containing thermally inactivated L. salivarius reduces the 12-month caries increment compared to the control group. The investigation was a single-center, randomized, controlled open-label, blinded end-point evaluation trial in two parallel groups. At baseline, 140 generally healthy children between 3 and 6 years of age with or without ECC were randomly assigned to the probiotic test group (n = 70) or to the treatment as the usual control group (n = 70). The primary outcome measure was the 1-year increment in caries incidence and prevalence. Secondary endpoints assessed were the initial, cavitated and obvious dentinal caries increment as well as the measurement of dental plaque accumulation, as an indicator of the ECC risk. Data were collected through the clinical assessment of the children's caries (dmft and ICDAS II) and oral hygiene status (DI-S of OHI-S index). Caries incidence and prevalence were statistically significantly lower in the probiotic group versus the control group (p < 0.001 and p = 0.0075). The initial and final mean OHI-S scores in the probiotic group did not show any significant differences. In conclusion, the regular short-term intake of probiotics may reduce caries development. Our findings suggest that self-administered probiotic therapy may provide a good complement to increase the effectiveness of individual preventive home care in preschool children. This is the first clinical study evaluating the effect of a short-term probiotic intervention on reducing early childhood caries with 12 months of follow-up.

The Effect of Probiotics Use on Salivary Cariogenic Bacteria in Orthodontic Patients with Various Caries Risk Status

Background: The purpose of this study was to evaluate the change in intraoral cariogenic bacteria density after probiotic use in patients with orthodontic treatment, and to compare the impact of probiotics in patients with various caries risk status. Methods: Patients that planned to receive orthodontic treatment were recruited according to this study’s inclusion/exclusion criteria. A probiotic prescription (Lactobacteria 3 mg, Glycobacteria 2 mg) was started one month after the initial orthodontic treatment. Saliva sampling and cultures using a CRT kit (caries risk test) were performed at three time points (T0, T1, T2). Mutans streptococci (MS) and Lactobacilli (LB) density were evaluated and scored using the interpretation chart in the CRT kit to evaluate the change in bacteria density at three time points, to define the high and low caries risk prior to orthodontic treatment, and to evaluate if there were differences in probiotics between the high and low caries risk groups. Results: Thirty-three orthodontic patients were enrolled, twenty-two classified as high caries risk and eleven as low caries risk. After undergoing treatment for one month, the densities of MS and LB increased significantly (p = 0.011, p = 0.001); probiotics for one month decreased the density of MS and LB, but the differences were statistically nonsignificant (p = 0.109, p = 0.109). Patients classified as low risk of caries demonstrated an increase in MS and LB density one month after orthodontic treatment (p = 0.024, p = 0.001), probiotic use did not result in a significant reduction in bacteria density (p = 1000, p = 0.933). In patients with high caries risk, there were no statistically significant changes in MS count between the three time points (p = 0.127); a significant change in LB density occurred at T0–T1 (p = 0.011) only. Conclusions: Supplemental use of probiotic oral tablets during orthodontic treatment aimed at reducing cariogenic bacteria count in saliva did not achieve significant differences, regardless of patients’ risk status for caries.

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.

A programmable encapsulation system improves delivery of therapeutic bacteria in mice

Living bacteria therapies have been proposed as an alternative approach to treating a broad array of cancers. In this study, we developed a genetically encoded microbial encapsulation system with tunable and dynamic expression of surface capsular polysaccharides that enhances systemic delivery. Based on a small RNA screen of capsular biosynthesis pathways, we constructed inducible synthetic gene circuits that regulate bacterial encapsulation in Escherichia coli Nissle 1917. These bacteria are capable of temporarily evading immune attack, whereas subsequent loss of encapsulation results in effective clearance in vivo. This dynamic delivery strategy enabled a ten-fold increase in maximum tolerated dose of bacteria and improved anti-tumor efficacy in murine models of cancer. Furthermore, in situ encapsulation increased the fraction of microbial translocation among mouse tumors, leading to efficacy in distal tumors. The programmable encapsulation system promises to enhance the therapeutic utility of living engineered bacteria for cancer.

Transient capsule induction allows engineered bacteria to evade initial immune surveillance in a colorectal cancer model.

Effectiveness and safety of Bifidobacterium in preventing dental caries: a systematic review and meta-analysis

OBJECTIVES

The effectiveness and safety of Bifidobacterium in dental caries prevention are controversial. Thus, we performed this systematic review and meta-analysis to explore the preventive value of Bifidobacterium.

METHODS

Eligible studies were identified from several databases, including PubMed, the Cochrane Library, Embase, Web of Science, and Scopus. Hand searches were also conducted in relevant bibliographies. We then extracted and pooled standardized mean difference (SMD) and risk ratio (RR) to analyze the anti-caries effect of Bifidobacterium with Stata 16.0 software. If the data obtained was not suitable for meta-analysis, qualitative descriptions were performed.

RESULTS

Compared with the placebo control group, there was no statistically significant reduction in Streptococcus mutans and Lactobacilli counts in saliva in the test group. Also, there were no significant differences in Streptococcus mutans and Lactobacillus counts in dental plaque and no significant difference in caries incidence in deciduous teeth. There was no significant difference in the incidence of adverse events between the Bifidobacterium and control groups.

CONCLUSIONS

Available evidence demonstrates that Bifidobacterium is neither effective in reducing Streptococcus mutans and Lactobacillus counts in the saliva or dental plaque nor in reducing the occurrence of caries in deciduous teeth. Evaluation of its safety requires further investigations. Therefore, Bifidobacterium is not a competent probiotic candidate to prevent dental caries.

Comparative Evaluation of the Effect of 0.2% Chlorhexidine, 2% LemonGrass Oil, and 2% Tea Tree Oil Mouth rinse on Salivary pH: An In vivo Study

Background:

Mouthwashes containing essential oils are used in the prevention and treatment of periodontal diseases. Lemongrass oil (LGO) belongs to a section of andropogen called cymbogam of the family germineae and from it, the LGO is extracted. Tea tree oil (TTO) is extracted from Melaleuca alternifolia leaves (Myrtaceae family).

Aim and Objective:

The aim of the study is to evaluate the pH of saliva before and after using LGO and TTO mouth rinse and to determine its relevance to the oral health status.

Materials and Methods:

A purposive sample of 90 participants aged between 26 and 38 years were included in the study. The PH before and after the use of the chlorhexidine, LGO, and TTO mouthwashes are noted using the GC PH strips and a comparative study was made. Statistical analysis was performed using paired t-test. P < 0.05 was considered statistically significant.

Results:

Comparative analysis was made with Wilcoxon signed-ranks test and found that the TTO gives a greater increase in salivary pH with a P = 0.001** (P < 0.05) which is found to be statistically significant.

Conclusion:

The study conducted shows beneficial effects of TTO and LGO mouth rinse. Further studies with larger samples may produce more reliable values.

Small molecule natural products in human nasal/oral microbiota

Small molecule natural products are a chemically diverse class of biomolecules that fulfill myriad biological functions, including autoregulation, communication with microbial neighbors and the host, interference competition, nutrient acquisition, and resistance to oxidative stress. Human commensal bacteria are increasingly recognized as a potential source of new natural products, which may provide insight into the molecular ecology of many different human body sites as well as novel scaffolds for therapeutic development. Here, we review the scientific literature on natural products derived from residents of the human nasal/oral cavity, discuss their discovery, biosynthesis, and ecological roles, and identify key questions in the study of these compounds.

Effect of the local probiotics in the therapy of periodontitis A randomized prospective study

OBJECTIVES

The use of local probiotics in the therapy of periodontitis is reflected in their ability to antagonize periodontopathogens and modulates the immune response of the host to the presence of pathogenic microorganisms. The aim of this study was to investigate the use of local probiotics in the treatment of periodontitis as an adjunctive therapy to scaling and root planning (SRP).

METHODS

The study involved 80 patients diagnosed with periodontitis. All participants underwent SRP therapy. Semi-solid probiotic was then locally applied to the periodontal pocket in randomly selected patients for the test group (40 of them). The other 40 patients were in the control group. Clinical parameters including periodontal pocket depth (PPD), bleeding on probing (BOP) and plaque index (PI) were measured at baseline, and at 7 and 30 days after treatment.

RESULTS

Seven days after the applied therapy in the test and control group, there was a significant decrease in the values or BOP (p < .001), while the values of other parameters did not show a statistically significant difference (p < .05). One month after the therapy in both groups, there was a statistically significant difference in the values of all clinical parameters (p < .001).

CONCLUSIONS

Based on the results of this pilot study, it can be said that, during periodontal treatment, topical application of probiotics in combination with SRP increases the effectiveness of conventional non-surgical therapy of periodontitis.

Inhibition of Streptococcus mutans biofilm formation by strategies targeting the metabolism of exopolysaccharides

Dental caries is one of the most prevalent and costly biofilm-associated infectious diseases affecting most of the world's population. In particular, dental caries is driven by dysbiosis of the dental biofilm adherent to the enamel surface. Specific types of acid-producing bacteria, especially Streptococcus mutans, colonize the dental surface and cause damage to the hard tooth structure in the presence of fermentable carbohydrates. Streptococcus mutans has been established as the major cariogenic pathogen responsible for human dental caries, with a high ability to form biofilms. The exopolysaccharide (EPS) matrix, mainly contributed by S. mutans, has been considered as a virulence determinant of cariogenic biofilm. As EPS is an important virulence factor, targeting EPS metabolism could be useful in preventing cariogenic biofilm formation. This review summarizes plausible strategies targeting S. mutans biofilms by degrading EPS structure, inhibiting EPS production, and disturbing the EPS metabolism-related gene expression and regulatory systems.

Impact of Probiotics on the Salivary Microbiota and Salivary Levels of Inflammation-Related Proteins during Short-Term Sugar Stress: A Randomized Controlled Trial

Background: The purpose of the present investigation was to characterize the effect of probiotics on the composition of the salivary microbiota and salivary levels of inflammation-related proteins during short-term sugar stress. We tested the hypotheses that consumption of probiotics may partly counteract the detrimental influence of sugar stress on oral homeostasis. Methods: The present study was a five-week, blinded, randomized controlled trial with four study arms—A: sucrose and probiotic (n = 20); B: sucrose and placebo (n = 20); C: xylitol and probiotic (n = 20); D: xylitol and placebo (n = 20). Saliva samples were collected at baseline and after two and five weeks. The salivary microbiota was characterized by means of 16S rDNA sequencing, and sequences were referenced against the Human Oral Microbiome Database (HOMD). Neutrophil gelatinase-associated lipocalin (NGAL) and transferrin levels were quantified using immunoassays. Results: Sugar stress induced a significant increase in the relative abundance of the genus Streptococcus from 29.8% at baseline to 42.9% after two weeks. Changes were transient and were completely reversed three weeks after discontinuation of sugar stress. Xylitol and probiotics alone had no effect on the salivary microbiota, whereas the combination of xylitol and probiotics induced a significant decrease in the relative abundance of Streptococcus species from 37.6% at baseline to 23.0% at week 2. Sugar stress significantly increased salivary transferrin levels, and the effect was partly counteracted by concomitant use of probiotics. Conclusions: The data clearly demonstrate an impact of combined consumption of xylitol and probiotics on the composition of the salivary microbiota. Future studies are needed to evaluate whether the combined use of xylitol and the probiotic strains tested could have clinically protective effects during periods of sugar stress.

Probiotics Do Not Alter the Long-Term Stability of the Supragingival Microbiota in Healthy Subjects: A Randomized Controlled Trial

Background: The purpose of the present study was to longitudinally characterize the supragingival microbiota throughout a three months period in orally healthy individuals. We tested the hypothesis that the supragingival microbiota shows a high degree of compositional stability, which is resilient against the external perturbation of regular use of probiotics, as long as oral health is maintained. Methods: The present study was a double-blinded, randomized, placebo-controlled clinical trial. The study population comprised a total of 110 oral and systemic healthy individuals, distributed in a probiotic (n = 55) and placebo (n = 55) group, where the test group consumed tablets with the probiotic strains Lacticaseibacillusrhamnosus (formerly Lactobacillus) PB01 DSM14870 and Latilactobacillus curvatus (formerly Lactobacillus) EB10 DSM32307 for a period of 12 weeks. Supragingival plaque samples and clinical registrations were performed at baseline, and after 4, 8, and 12 weeks, respectively. The supragingival microbiota was characterized by means of 16S rDNA sequencing. Sequences were referenced against the HOMD database. Results: No significant changes of the core microbiota, as expressed by relative abundance of predominant genera and species were evident during the three months observation period in the probiotic or the placebo group. Conclusions: Data from the present study clearly demonstrate long term compositional stability of the supragingival microbiota as long as oral health is maintained. In addition, the tested probiotics had no augmenting effect on the supragingival microbiota in oral health.

Quantification and gene expression of Lactobacillus casei group species associated with dentinal lesions in early childhood caries

Background

Considering that the Lactobacillus casei group is strongly associated with caries progression, the use of lactobacilli as probiotics must be balanced due to their possible involvement in dental caries.

Objective

This study aimed to detect and quantify L. paracasei, L. rhamnosus, and L. casei group species in the active and arrested dentinal lesions of preschoolers. It also aimed to determine the expression profiles of lactobacilli genes related to adhesion, extracellular polymeric substance regulation, and pyruvate oxidation.

Methods

Total ribonucleic acid (RNA) was extracted from dentinal lesion samples (25 active, 13 arrested) of children between 2 and 5 years of age. The samples were converted to complementary deoxyribonucleic acid (cDNA), and quantitative polymerase chain reaction (qPCR) analyses were performed to quantify and determine the relative abundance (measured by percentage of total bacteria) of L. paracasei, L. rhamnosus, and L. casei group species. The expression profiles of L. paracasei/casei genes (spaC and spxB) and L. rhamnosus genes (spaE and wzb) were assessed. The Student t-test and the Mann-Whitney U test were used for comparisons.

Results

The L. casei group species were found to be part of the viable microbial community in dentinal caries. L. paracasei (p = 0.001), L. rhamnosus (p = 0.022), and L. casei (p = 0.004) group species were abundant in the active dentinal lesions compared to the arrested dentinal lesions. Only the wzb gene (p = 0.006) exhibited a statistically significant difference between the active and arrested lesions in terms of its expression profile; it was expressed to a higher extent in the active dentinal lesions.

Conclusions

The L. casei group species presented in large numbers in the active dentinal caries lesions, indicating that these microorganisms are related to caries activity, and the wzb gene may play an important role in caries progression.

Fermented milk containing a potential probiotic Lactobacillus rhamnosus SD11 with maltitol reduces Streptococcus mutans: A double-blind, randomized, controlled study

Background/purpose

Sucrose has been considered as a cariogenic substrate due to large amounts of acid production after fermentation by certain oral bacteria, thus sugar alcohols are often used to replace sucrose. The aims of this study were to investigate the effect of maltitol on the growth and acid production of Streptococcus mutans and Lactobacillus rhamnosus-SD11 compared to various sugars, and to examine whether the fermented milk containing a potential probiotic L. rhamnosus-SD11 with maltitol could reduce S. mutans.

Materials and methods

The acid production of tested sugars by cariogenic S. mutans was measured using pH meter. In a clinical trial, 123 children were recruited and randomly assigned to either the probiotic- or control-fermented milk, once daily for 4 weeks. The target bacteria levels in the saliva were examined using a real-time PCR at baseline, 4 and 8 weeks. The oral examination was recorded at the baseline and 8 weeks.

Results

The results showed that maltitol exhibited less acid production than simple sugars. In the clinical trial, a significant reduction of salivary total streptococci and S. mutans occurred, while the levels of salivary lactobacilli significantly increased in the probiotic group compared to the control group after receiving the probiotic fermented milk.

Conclusion

The daily consumption of the fermented milk containing L. rhamnosus-SD11 with maltitol had beneficial effects on oral health by reducing salivary S. mutans. Thus, the substitution of simple sugars by maltitol in dairy products containing L. rhamnosus-SD11 may be an alternative way to prevent the risk of caries.

Combined effect of arginine and fluoride on the growth of Lactobacillus rhamnosus GG

The objectives of the in vitro study were: (1) to investigate the effect of combining L-arginine (Arg) and NaF on the growth of Lactobacillus rhamnosus GG (LRG); and (2) to identify an optimum synergistic concentration for the synbiotic (Arg + LRG)-fluoride (SF) therapy. 1% Arg + 2000-ppm NaF (A-SF) and 2% Arg + 2000-ppm NaF (B-SF) demonstrated antagonism against LRG (FIC > 4.0). Both XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) assays showed that A-SF and B-SF enhanced the growth of LRG when compared to 2000-ppm NaF and LRG control. Colony forming units, bacterial weight, and biofilm thickness of A-SF and B-SF were significantly higher than 2000-ppm NaF and LRG control. Biofilm imaging depicted that 2000-ppm NaF inhibited biofilm formation; while 1%/2% Arg, A-SF, and B-SF increased biofilm growth of LRG. Lactic acid formation was the lowest for 2000-ppm NaF, followed by A-SF and then B-SF. The SF buffer potential after 24 h was the highest for B-SF, and then A-SF. Biofilm pH for B-SF was closest to neutral. Fluoride, Arg and LRG bioavailability remained unaffected in B-SF. The relative gene expression for arcA, argG, and argH was significantly higher for B-SF than the respective controls. In conclusion, combining 2% Arg, 2000-ppm NaF, and LRG provides an optimum synbiotic-fluoride synergism.

Effect of Lactobacillus brevis CD2 containing lozenges and plaque pH and cariogenic bacteria in diabetic children: a randomised clinical trial

Objective

The short-term effect (60 days) of Lactobacillus brevis CD2 lozenges vs placebo on variables related to caries and gingivitis in type 1 diabetic children was evaluated.

Material and methods

Eight diabetics (4–14 years old) were assigned to two groups (n = 34 subjects each), probiotic lozenges and placebo. Stimulated saliva for microbiological analysis and plaque pH were assessed at baseline (t₀), 30 days (t₁), 60 days (t₂) and in the follow-up period (90 days from baseline, t₃). Gingival status was assessed at t₀, t₂ and t₃. Two-way ANOVA assessed differences between groups.

Results

In the probiotic group, Streptococcus mutans bacterial density mean scores dropped from 3.11 ± 1.13 at baseline to 1.82 ± 0.72 (t₂) and to 2.06 ± 0.56 (t₃), while in the placebo group, the scores were 3.09 ± 0.8 (t₀), 2.82 ± 0.47 (t₂) and 3.11 ± 0.43 (t₃) (p < 0.01). Lowest and maximum pH fall increased in the probiotic group, from 5.37 ± 0.41 at baseline to 5.49 ± 0.24 at t₃ (p < 0.01) and from 1.20 ± 0.46 to 0.98 ± 0.29 (p = 0.02). Bleeding score decreased significantly in both groups, showing a statistically significant lower bleeding score at t₂ in the probiotic group (25.6%, 95% CI 21.5–32.7 vs 29.5%, 95% CI 25.2–34.9, p = 0.02).

Conclusions

Lactobacillus brevis CD2 has shown to improve caries-related risk factors and gingival health in diabetic children.

Clinical relevance

Lactobacillus brevis CD2 might contribute to improved oral health in type 1 diabetic children.

Electronic supplementary material

The online version of this article (10.1007/s00784-020-03342-0) contains supplementary material, which is available to authorized users.

The potential of Streptococcus salivarius oral films in the management of dental caries: An inkjet printing approach

The use of probiotics, which can be administered in oro-dispersible films (ODFs) and have prolonged activity in the mouth, was explored. ODFs made of xylitol and containing Streptococcus salivarius were formulated using inkjet printing and tested against Streptococcus mutans - a causative organism of dental caries. The testing of the prepared ODFs involved co-incubating an ink-jetted formulation of S. salivarius and xylitol with S. mutans and monitoring the microbial growth kinetics in real-time using isothermal microcalorimetry and colony plate counts. Cell-free supernatants (CFS) of S. salivarius were also tested against S. mutans. The phosphate solubilisation potential of S. salivarius was also determined and found to be negative, an indication that the species will not deplete phosphate from teeth. From the tests, it was observed that the formulation reduced the S. mutans population from 7.9 to 5.04 Log CFU/mL post-calorimetry (approximately 3 Log reduction) which was comparable to the 99.9% reduction expected during antimicrobial activity testing. A gradual decrease in S. mutans population was also observed with increasing of CFS of S. salivarius volumes indicative of pathogen suppression. This study demonstrates that S. salivarius can be useful in managing dental caries and ODFs of S. salivarius can be formulated easily using ink-jetting for such management.

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.

Effect of Green Tea Extract Mouthrinse and Probiotic Mouthrinse on Salivary pH in a Group of Schoolchildren: An In Vivo Study

Aim and Objective:

The aim of the study was to assess the efficacy of probiotic and green tea mouthrinse on salivary pH.

Materials and Methods:

This study was conducted over a period of 1 month among 40 healthy schoolchildren aged between 6 and 8 years. The subjects who fulfilled inclusion criteria were selected and randomly divided into two groups, namely probiotic and green tea groups. Salivary pH was recorded at baseline (0 day) and at the end of the specified time using GC pH strips. Statistical analysis was done using paired t test. P < 0.05 was considered statistically significant.

Result:

The comparison of mean pH scores for green tea showed that the pH of saliva was increased in the children after rinsing with green tea (6.00–7.60) and was statistically significant (P < 0.001). Similarly, when pre- and post-mean pH was compared in the probiotic group, the pH was found to be higher in the probiotic rinse group (5.60–7.20). The results were statistically significant.

Conclusion:

The study conducted shows the beneficial effects of green tea in providing a alkaline environment, which is conducive to the oral health of children.

Synbiotics in caries prevention: A scoping review

The scoping review aimed to examine the evidence on the role of synbiotics in caries prevention. PubMed, SCOPUS, and Web of Science databases search were performed. Any in vitro study, clinical trial, systematic review with/without meta-analysis, umbrella review/meta-evaluation, narrative review addressing the role of synbiotics in caries prevention were included in the scoping review. Data were extracted from the included studies using pre-approved registered protocol. Twenty-eight records were identified, of which 5 in vitro studies, 1 quasi-experimental clinical trial and 1 narrative review were included in the present review. No controlled clinical trials or systematic reviews on the role of synbiotics in caries prevention could be identified. Except 1, all in vitro studies examined the combined effect of saccharides and lactobacilli spp. as potential synbiotics on the growth of Streptococcus mutans. However, the proposed synbiotics in 4 in vitro studies either did not qualify or remained ambiguous of its eligibility as a potential synbiotic for caries prevention. One recent in vitro study explored the possibility of L-arginine and Lactobacillus rhamnosus GG synbiotic for caries prevention. The quasi-experimental clinical study without a control arm did not explicitly mention the intervention composition and thus, its synbiotic potential remains unclear. A narrative review highlighted the potential of combining arginine (prebiotic) with arginolytic bacteria (probiotic) as a synbiotic, which appears promising for caries prevention. The eligibility of the proposed synbiotics as a true synbiotic needs to be carefully addressed. Due to a lack of controlled clinical studies on synbiotics for caries prevention, evidence on their caries-preventive potential is weak. Future studies are needed to examine the combination of amino acids (esp. arginine) with probiotics as a potential synbiotic against cariogenic pathogens.

Microporous Frameworks as Promising Platforms for Antibacterial Strategies Against Oral Diseases

Nowadays, the heavy burden of oral diseases such as dental caries, periodontitis, endodontic infections, etc., and their consequences on the patients' quality of life indicate a strong need for developing effective therapies. Bacterial infections played an important role in the field of oral diseases, in-depth insight of such oral diseases have given rise to the demand for antibacterial therapeutic strategies. Recently, microporous frameworks have attracted tremendous interest in antibacterial application due to their well-defined porous structures for drug delivery. In addition, intensive efforts have been made to enhance the antibacterial performance of microporous frameworks, such as ion doping, photosensitizer incorporation as building blocks, and surface modifications. This review article aims on the major recent developments of microporous frameworks for antibacterial applications against oral diseases. The first part of this paper puts concentration on the cutting-edge researches on the versatile antibacterial strategies of microporous materials via drug delivery, inherent activity, and structural modification. The second part discusses the antibacterial applications of microporous frameworks against oral diseases. The applications of microporous frameworks not only have promising therapeutic potential to inhibit bacterial plaque-initiated oral infectious diseases, but also have a wide applicability to other biomedical applications.

Antimicrobial activity of Lactobacillus fermentum TcUESC01 against Streptococcus mutans UA159

Dental caries is a multifactorial chronic-infection disease, which starts with a bacterial biofilm formation caused mainly by Streptococcus mutans. The use of probiotics has shown numerous health benefits, including in the fight against oral diseases. Strains of Lactobacillus fermentum have already shown probiotic potential against S. mutans, but there are still few studies. Thus, the aim of our study was to evaluate the antimicrobial activity of the inoculum and metabolites produced by L. fermentum TcUESC01 against S. mutans UA159. For this, a growth curve of L. fermentum was performed and both the inoculum and the metabolites formed in the fermentation were tested against the growth of S. mutans UA159 in agar diffusion tests, and only its metabolites were tested to determine the minimum inhibitory concentration, minimal bactericidal concentration and inhibition of cell adhesion. Inhibition of biofilm formation, pH drop and proton permeability were also tested with the metabolites. The zone of inhibition began to be formed at 14 h and continued until 16 h. The inoculum containing L. fermentum also showed zone of inhibition. The MIC for the metabolites was 1280 mg/mL and the MBC was obtained with a concentration higher than the MIC equal to 5120 mg/mL. Half of the MIC concentration (640 mg/mL) was required to inhibit S. mutans adhesion to the surface of the microplates. In the biofilm analyzes, the treatment with the metabolites in the tested concentration was not able to reduce biomass, insoluble glucans and alkali soluble compared to the control biofilm (p > 0.05). The metabolites also did not affect acid production and acid tolerance of S. mutans cells in biofilms compared to saline group (p > 0.05). Lactic acid (50.38%) was the most abundant organic acid produced by L. fermentum. This is the first report showing that the metabolites produced by the Lactobacillus fermentum TcUESC01 have a potential to be used as an antimicrobial agent against S. mutans, showing anti-adherence and bactericidal activity against planktonic cells of S. mutans. Thus, further studies should be carried out in order to better understand the antimicrobial activity of metabolites of L. fermentum TCUESC01.

Efficiency of desensitizing materials in xerostomic patients with head and neck cancer: a comparative clinical study

OBJECTIVES

To assess the clinical effectiveness of four desensitizing materials in patients who are xerostomic due to radiotherapy for head and neck cancer (HNC) in comparison to a healthy group with normal salivation.

METHODS AND MATERIALS

The study was conducted as a split-mouth randomized clinical trial. Forty HNC patients (group A) and 46 healthy patients (group B) suffering from dentin hypersensitivity (DH) were included. Salivary flow was determined through a scialometric test. Hypersensitivity was assessed with air stimulus and tactile stimulus. The materials used as desensitizing agents were Vertise Flow, Universal Dentin Sealant, Clearfil Protect Bond, and Flor-Opal Varnish. The response was recorded before application of the materials, immediately after, and at 1 week, 4 weeks, and 12 weeks.

RESULTS

Salivary flow rates in groups A/B were 0.15/0.53 mL/min (unstimulated) and 0.54/1.27 mL/min (stimulated), respectively. In group A, 100 hypersensitive teeth were included. Application of the desensitizing agents significantly decreased the hypersensitivity immediately and throughout the 4-week follow-up (p < 0.001). However, after the 12-week timepoint, a loss of efficacy was detected in all agents (p = 0.131). In group B, 116 hypersensitive teeth were included. The materials performed a more stable action, although a loss of effectiveness was detected at 12-week control (p = 0.297).

CONCLUSION

The efficiency of the desensitizing agents after the first application was similar in both groups. In the radiated group, this effect lasted for shorter periods than in healthy controls.

CLINICAL RELEVANCE

HNC patients with hyposalivation may be a new risk group for DH.

Approaches to Modulate Biofilm Ecology

Dental caries is closely related to a dysbiosis of the microbial consortia of supragingival oral biofilms driven by a sugar-frequent and acidic-pH environment. The pH is a key factor affecting the homeostasis of supragingival biofilms seen in health. There is increasing interest on the ecological dynamics of the oral microbiome and how a dysbiotic microbiota can be successfully replaced by health-beneficial flora. The concept of preventing the microbial dysbiosis related to caries through modulation of sugar intake and pH has fully emerged.

Promising Alternative Therapeutics for Oral Candidiasis

:

Candida is the main human fungal pathogen causing infections (candidiasis), mostly in the elderly and immunocompromised hosts. Even though Candida spp. is a member of the oral microbiota in symbiosis, in some circumstances, it can cause microbial imbalance leading to dysbiosis, resulting in oral diseases. Alternative therapies are urgently needed to treat oral candidiasis (usually associated to biofilms), as several antifungal drugs’ activity has been compromised. This has occurred especially due to an increasing occurrence of drugresistant in Candida spp. strains. The overuse of antifungal medications, systemic toxicity, cross-reactivity with other drugs and a presently low number of drug molecules with antifungal activity, have contributed to important clinical limitations.

:

We undertook a structured search of bibliographic databases (PubMed Central, Elsevier’s ScienceDirect, SCOPUS and Springer’s SpringerLink) for peer-reviewed research literature using a focused review in the areas of alternatives to manage oral candidiasis. The keywords used were “candidiasis”, “oral candidiasis”, “biofilm + candida”, “alternative treatment”, “combination therapy + candida” and the reports from the last 10 to 15 years were considered for this review.

:

This review identified several promising new approaches in the treatment of oral candidiasis: combination anti-Candida therapies, denture cleansers, mouth rinses as alternatives for disrupting candidal biofilms, natural compounds (e.g. honey, probiotics, plant extracts and essential oils) and photodynamic therapy.

:

The findings of this review confirm the importance and the urgency of the development of efficacious therapies for oral candidal infections.

Saccharomyces cerevisiae CNCM I-3856 as a New Therapeutic Agent Against Oropharyngeal Candidiasis

Oropharyngeal candidiasis is a common opportunistic mucosal infection of the oral cavity, mainly caused by an overgrowth of Candida albicans. This infection can inhibit nutritional intakes and strongly affect quality of life. To date, standard therapeutic strategies involving the administration of antifungal drugs can bring several side effects, not least the emergence of drug-resistant strains. The purpose of this study is to investigate the effectiveness of Saccharomyces cerevisiae CNCM I-3856 (live or inactivated cells) against oropharyngeal candidiasis. Our results show that administration of S. cerevisiae CNCM I-3856 (live or inactivated cells) in the oral cavity of C57BL/6J mice resulted in a protective effect against oropharyngeal candidiasis. The strongest effect was obtained with live S. cerevisiae CNCM I-3856. This was related to: (1) a decrease in C. albicans load in the oral cavity, esophagus, stomach, and duodenum; (2) an early resolution of inflammatory process in the tongue; (3) a marked reduction in C. albicans virulence factors; and (4) a consistent increase in neutrophil antimicrobial capacity. These findings suggest that S. cerevisiae products are potentially beneficial in the treatment of oropharyngeal candidiasis.

Dietary Nitrite Drives Disease Outcomes in Oral Polymicrobial Infections

Streptococcus mutans resides in the oral polymicrobial biofilm and is a major contributor to the development of dental caries. Interestingly, high salivary nitrite concentrations have been associated with a decreased prevalence of dental caries. Moreover, the combination of hydrogen peroxide-producing oral commensal streptococci and nitrite has been shown to mediate the generation of reactive nitrogen species, which have antimicrobial activity. The goal of this study was to examine whether nitrite affects S. mutans virulence during polymicrobial infections with the commensal Streptococcus parasanguinis. Here, we report that the combination of S. parasanguinis and nitrite inhibited S. mutans growth and biofilm formation in vitro. Glucan production, which is critical for S. mutans biofilm formation, was also inhibited in 2-species biofilms with S. parasanguinis containing nitrite as compared with biofilms that contained no nitrite. In the in vivo caries model, enamel and dentin carious lesions were significantly reduced in rats that were colonized with S. parasanguinis prior to infection with S. mutans and received nitrite in the drinking water, as compared with animals that had a single S. mutans infection or were co-colonized with both bacteria and received no nitrite. Last, we report that S. mutans LiaS, a sensor kinase of the LiaFSR 3-component system, mediates resistance to nitrosative stress. In summary, our data demonstrate that commensal streptococci and nitrite provide protection against S. mutans pathogenesis. Modulating nitrite concentrations in the oral cavity could be a useful strategy to combat the prevalence of dental caries.

Oral probiotics reduce halitosis in patients wearing orthodontic braces: a randomized, triple-blind, placebo-controlled trial

Orthodontic braces can impede oral hygiene and promote halitosis. The aim of the study was to investigate the effect of the oral probiotic Streptococcus salivarius M18 on oral hygiene indices and halitosis in patients wearing orthodontic braces. The study was a prospective, randomized, triple-blind, placebo-controlled trial. Patients undergoing fixed orthodontic treatment were randomly allocated to a probiotic group (n = 32) and a placebo group (n = 32). Patients consumed 2 lozenges d^-1 for one month. Assessments were taken at baseline, at the end of the intervention, and at a 3 month follow-up. The outcome measures were plaque index (PI), gingival index (GI) and halitosis-causing volatile sulfur compound (VSC) levels. The dental biofilms before and after the intervention were analyzed utilizing next-generation sequencing of bacterial 16S rRNA genes. PI and GI scores were not significantly influenced by the probiotic intervention (intervention × time: p > 0.05). The level of VSCs decreased significantly in both the probiotic group (VSC reduction = -8.5%, 95%CI = -7.4% to -9.1%, p = 0.015) and the placebo group (-6.5%, 95%CI = -6.0% to -7.4%, p = 0.039) after 1 month intervention. However, at the 3 month follow-up, the VSC levels in the placebo group returned to baseline levels whereas those in the probiotic group decreased further (-10.8%, 95%CI = -10.5% to -12.9%, p = 0.005). Time, but not treatment, was associated with the decrease in microbial community alpha diversity and a modest effect on beta diversity. Oral probiotic S. salivarius M18 reduced the level of halitosis in patients with orthodontic braces, but had minimal effects on PI, GI and dental biofilm microflora.

Critical Appraisal of Oral Pre- and Probiotics for Caries Prevention and Care

In recent years, the concept of preventing caries-related microbial dysbiosis by enhancing the growth and survival of health-associated oral microbiota has emerged. In this article, the current evidence for the role of oral pre- and probiotics in caries prevention and caries management is discussed. Prebiotics are defined as "substrates that are selectively utilized by host microorganisms conferring a health benefit." With regard to caries, this would include alkali-generating substances such as urea and arginine, which are metabolized by some oral bacteria, resulting in ammonia production and increase in pH. While there is no evidence that urea added to chewing gums or mouth rinses significantly contributes to caries inhibition, multiple studies have shown that arginine in consumer products can exert an inhibitory effect on the caries process. Probiotics are "live microorganisms which when administrated in adequate amounts confer a health benefit on the host." Clinical trials have suggested that school-based programs with milk supplemented with probiotics and probiotic lozenges can reduce caries development in preschool children and in schoolchildren with high caries risk. Due to issues with research ethics (prebiotics) and risk of bias (prebiotics, probiotics), the confidence in the effect estimate is however limited. Further long-term clinical studies are needed with orally derived probiotic candidates, including the health-economic perspectives. In particular, the development and evaluation of oral synbiotic products, containing both prebiotics and a probiotic, would be of interest in the future management of dental caries.

Antagonistic effects of Streptococcus and Lactobacillus probiotics in pharyngeal biofilms

Direct antagonism towards pathogens including Streptococcus pyogenes is a proposed mechanism of pharyngeal probiosis but off-target effects on the symbiotic microbiota of the throat are possible and may be beneficial, harmful or neutral. We have assessed the bacteriological effects of two candidate Lactobacillus probiotics and the established pharyngeal probiotic Streptococcus salivarius K12. Antagonism towards S. pyogenes and potential off-target effects were determined using sessile monospecies biofilms and pharyngeal microcosms, respectively. The candidate probiotics were antagonistic towards S. pyogenes (rank order of increasing potency, Lactobacillus acidophilus < Lactobacillus plantarum < Streptococcus salivarius) in the absence of significant acidification or cell-cell contact. Streptococcus salivarius and L. plantarum caused significant reductions in viable counts of streptococci in pharyngeal microbiotas, whilst S. salivarius also caused reductions in staphylococci. In contrast, changes in pharyngeal eubacterial DNA profiles were limited overall. In summary, the three candidate probiotics suppressed axenic Streptococcus pyogenes biofilms by mechanisms that did not depend on cell-cell contact or acidification and did not markedly destabilize complex pharyngeal microbiotas derived from healthy individuals. SIGNIFICANCE AND IMPACT OF THE STUDY: Candidate probiotic bacteria deployed to prevent or treat bacterial pharyngitis will interact with the target bacteria such as Streptococcus pyogenes as well as with the microbiota of the throat, where off-target effects are possible. Three candidate probiotics Lactobacillus acidophilus, Lactobacillus plantarum and Streptococcus salivarius reduced viability within extant S. pyogenes biofilms through the elaboration of diffusible factors other than fermentation acids but did not markedly disrupt ex situ pharyngeal microcosms. This work demonstrates the application of in vitro pharyngeal models in the preclinical testing of the safety and efficacy of candidate pharyngeal probiotics.

Probiotic Streptococcus strains in caries prevention: A systematic review

Objective:

The aim of this article is to review the published literature with the purpose of knowing the importance of using various probiotic Streptococcus strains as a preventive and therapeutic method for dental caries management.

Materials and Methods:

Research question was formulated based on the PICO strategy. A comprehensive electronic literature search was conducted across PubMed/Medline, Scopus, and EBSCOhost databases independently by two reviewers. All papers published from 1989 to December 2017 that focused on the use of probiotic Streptococcus strains for caries prevention were included in this review. Inclusion and exclusion criteria were applied to the selected articles, and a customized data extraction sheet was formulated. The selected articles were subjected to quality assessment, and the risk of bias in selected studies was evaluated.

Results:

A total of five articles were included. The overall risk of bias of the selected clinical trials was found to be high risk, and the overall level of evidence of the selected in vitro studies was moderate.

Conclusion:

The two included clinical studies on the use of probiotic Streptococcus strains for caries prevention had high risk of bias. Although in-vitro studies showed promising results, clinical studies have not demonstrated clear clinical outcomes. Thus, there is a vast scope for future research in this field.

Clinical Relevance:

Application of oral probiotics will help reinstate a balanced microbiota and thereby improving oral health. This systematic review focused on evaluating the role played by probiotic Streptococcus strains in the carious lesion incidence.

Are dairy products containing probiotics beneficial for oral health? A systematic review and meta-analysis

OBJECTIVES

To evaluate the effect of probiotic containing in dairy products on oral and salivary parameters.

MATERIAL AND METHODS

Electronic searches were performed based on the PICO criteria. Randomized controlled trials in adults/children (P) in which dairy products containing probiotics (I) were compared to controls (C) for establishment of oral health (O) were included. Risk of bias and data extraction were performed. The meta-analysis evaluated the influence of probiotics on Streptococcus mutans (SM), Lactobacillus spp. (LB), and yeast counts, plaque index, and salivary pH. Random or fixed effect models were used, and heterogeneity was tested.

RESULTS

Thirty-two studies were included in the qualitative synthesis, and 24 in the meta-analysis. For dichotomous results, individuals who consumed probiotics exhibited decreased scores in SM concentrations (RD 0.15 [0.02, 0.28] p = 0.03, I² = 70%), but no change was observed for LB (RD 0.10 [- 0.03, 0.23] p = 0.13, I² = 94%), or yeast levels (RD 0.05 [- 0.02, 0.12] p = 0.7, I² = 48%). For continuous analysis, both probiotic and control groups presented similar results for SM and LB (MD - 0.55 [- 1.16, 0.07] p = 0.08, I² = 62%, and RD 0.10 [- 0.03, 0.23] p = 0.13, I² = 94%, respectively). The consumption of probiotics increased salivary pH (MD 0.20 [0.04, 0.35] p = 0.01, I² = 46%) and plaque index (MD 0.38 [0.11, 0.65] p = 0.005, I² = 0%). The probiotic milk reduced SM (MD - 0.59 [- 0.96, - 0.22] p = 0.002, I² = 0%), and the probiotic yogurt decreased LB counts (RD 0.35 [0.19, 0.51] p < 0.0001, I² = 0%).

CONCLUSIONS

In general, dairy probiotics were effective in reducing SM, increasing salivary pH, and promoting a higher plaque index. Liquid matrices, such as milk and yogurt, seem to be more effective in reducing SM and LB levels.

CLINICAL RELEVANCE

Consumption of dairy products containing probiotics could be a supporting method in caries prevention.