Probiotics: do they have a role in oral medicine and dentistry?

Vaginal prevention of Candida albicans: synergistic effect of lactobacilli and mannan oligosaccharides (MOS)

Vulvovaginal candidiasis (VVC) affects approximately 30-50% of women at least once during their lifetime, causing uncomfortable symptoms and limitations in their daily quality of life. Antifungal therapy is not very effective, does not prevent recurrencies and usually causes side effects. Therefore, alternative therapies are urgently needed. The goal of this work was to investigate the potential benefits of using mannan oligosaccharides (MOS) extracts together with a Lactobacillus sp. pool, composed by the most significant species present in the vaginal environment, to prevent infections by Candida albicans. Microbial growth of isolated strains of the main vaginal lactobacilli and Candida strains was assessed in the presence of MOS, to screen their impact upon growth. A pool of the lactobacilli was then tested against C. albicans in competition and prophylaxis studies; bacterial and yeast cell numbers were quantified in specific time points, and the above-mentioned studies were assessed in simulated vaginal fluid (SVF). Finally, adhesion to vaginal epithelial cells (HeLa) was also evaluated, once again resorting to simultaneous exposure (competition) or prophylaxis assays, aiming to measure the effect of MOS presence in pathogen adherence. Results demonstrated that MOS extracts have potential to prevent vaginal candidiasis in synergy with vaginal lactobacilli, with improved results than those obtained when using lactobacilli alone. KEY POINTS: Potential benefits of MOS extracts with vaginal lactobacilli to prevent C. albicans infections. MOS impacts on growth of vaginal lactobacilli pool and C. albicans in SVF. MOS extracts in synergy with L. crispatus inhibit C. albicans adhesion in HeLa cells.

Alteration of oral microbial biofilms by sweeteners

There is a growing interest in using sweeteners for taste improvement in the food and drink industry. Sweeteners were found to regulate the formation or dispersal of structural components of microbial biofilms. Dietary sugars may enhance biofilm formation and facilitate the development of antimicrobial resistance, which has become a major health issue worldwide. In contrast, bulk and non-nutritive sweeteners are also beneficial for managing microbial infections. This review discusses the clinical significance of oral biofilms formed upon the administration of nutritive and non-nutritive sweeteners. The underlying mechanism of action of sweeteners in the regulation of mono- or poly-microbial biofilm formation and destruction is comprehensively discussed. Bulk and non-nutritive sweeteners have also been used in conjunction with antimicrobial substances to reduce microbial biofilm formation. Formulations with bulk and non-nutritive sweeteners have been demonstrated to be particularly efficient in this regard. Finally, future perspectives with respect to advancing our understanding of mechanisms underlying biofilm regulation activities of sweeteners are presented as well. Several alternative strategies for the application of bulk sweeteners and non-nutritive sweeteners have been employed to control the biofilm-forming microbial pathogens. Gaining insight into the underlying mechanisms responsible for enhancing or inhibiting biofilm formation and virulence properties by both mono- and poly-microbial species in the presence of the sweetener is crucial for developing a therapeutic agent to manage microbial infections.

Utilization of Probiotics Among Dental Students: A KAP Study

Aim

The aim of the study is to know about the awareness of probiotics among undergraduate dental students.

Materials and Methods

We conducted cross-sectional research where we had distributed a questionnaire consisting of ten open-ended questions, among 150 dental students through emails. The questions were based on the utilization of probiotics in dentistry. The data obtained was statistically analyzed with the help of Chi-square test.

Results

In our study, we noted that most of the participants were aware of the term probiotics and had general ideas but were not fully aware of its pathogenesis. Around 83.2% of the participants were aware of probiotics and general concepts. We also noted that only 42.5% of the students agreed that probiotics can be used in the management of halitosis as well as periodontitis.

Conclusion

We concluded that most of the dental students had a lack of awareness as well as were not familiar with the usage of probiotics in dentistry.

Mechanism Insights of Antibacterial Surfaces Coated with Dead Probiotics

To understand the antimicrobial effect of surfaces fabricated with dead probiotics, we prepared surfaces decorated with dead probiotics Lactobacillus rhamnosus GG (LGG) with varied inactivation methods and explored their inhibitory interactions with Pseudomonas aeruginosa (PAO1). By combining several techniques, i.e., digital holographic microscopy (DHM), atomic force microscopy (AFM), RNA sequencing, and metabolomic analysis, we studied the three-dimensional (3D) swimming behaviors, surface adhesion, biofilm formation, and adaptive responses of PAO1 near such surfaces. The results show that planktonic PAO1 decreases their flick and reverse motions by downregulating the chemotaxis pathway and accelerates with less accumulation near dead LGG surfaces by upregulating the flagellar assembly pathway and decreasing cyclic adenosine monophosphate. Distinct from live siblings, the surfaces decorated with dead LGG show a significant reduction in adhesion strength with PAO1 and inhibit biofilm formation with more downregulated genes in the Pseudomonas quinolone signal and biofilm formation pathway. We demonstrate that the antibacterial ability of such surfaces stems from the gradually released lysate from the dead LGG that is unfavorable to PAO1 in close proximity. The releasing rate and order depend on the cell membrane integrity, which closely relates to the inactivation methods.

Efficacy of aloe vera and probiotic mouthwashes vs fluoride mouthwash on Streptococcus mutans in plaque around brackets of orthodontic patients: a randomized clinical trial

OBJECTIVES

To compare efficacy of aloe vera and probiotic mouthwashes vs fluoride mouthwash on Streptococcus mutans (S. mutans) in the plaque of orthodontic patients and to assess patient-reported outcomes and compliance.

MATERIALS AND METHODS

This prospective randomized clinical trial included 90 patients aged 12-35 years and in permanent dentition, who were randomly allocated in a 1:1:1 ratio to three mouthwash groups: aloe vera, probiotic, or fluoride. Smartphone-based applications were used to improve patient compliance. The primary outcome was the change in S. mutans levels in plaque between two times: pre-intervention and after 30 days using real-time polymerase chain reaction (Q-PCR). Secondary outcomes were the evaluation of patient-reported outcomes and compliance.

RESULTS

Mean differences between aloe vera vs probiotic: -0.53 (95% CI: -3.57 to 2.51), aloe vera vs fluoride: -1.99 (95% CI, -4.8 to 0.82), and probiotic vs fluoride: -1.46 (95% CI: -4.74 to 1.82) were not significant, P = .467. Intragroup comparison demonstrated a significant mean difference in all three groups of -0.67 (95% CI: -0.79 to -0.55), -1.27 (95% CI: -1.57 to -0.97), and -2.23 (95% CI: -2.44 to -2.00) respectively, P < .001. Adherence was above 95% in all groups. No significant differences in frequency of responses to patient-reported outcomes were found among groups.

CONCLUSIONS

No significant difference in efficacy among the three mouthwashes in reducing S. mutans level in plaque was found. Patient-reported assessments concerning burning sensation, taste, and tooth staining found no significant differences among mouthwashes. Smartphone-based applications can help improve patient compliance.

New Preventive Strategy against Oral Biofilm Formation in Caries-Active Children: An In Vitro Study

Quorum quenching (QQ) is the inhibition of bacterial communication, i.e., quorum sensing (QS). QS is a key mechanism in regulating biofilm formation and phenotype in complex bacterial communities, such as those found within cariogenic biofilms. Whereas QQ approaches were shown to effectively reduce biomass, knowledge of their impact on the taxonomic composition of oral polymicrobial biofilms remains scarce. Here, we investigate the effect of the QQ lactonase Aii20J on biomass production and taxonomical composition of biofilms. We collected supragingival plaque samples from 10 caries-free and 10 caries-active children and cultured them to generate in vitro biofilms. We describe significant biomass reductions upon Aii20J exposure, as assessed by crystal violet assays. Taxonomical profiling using 16S rRNA gene amplicon sequencing revealed no significant changes in bacterial composition at the genus level. Interestingly, at the species level Aii20J-treatment increased the abundance of Streptococcus cristatus and Streptococcus salivarius. Both S. cristatus and S. salivarius express pH-buffering enzymes (arginine deiminase and urease, respectively) that catalyze ammonia production, thereby potentially raising local pH and counteracting the biofilm's cariogenic potential. Within the limitations of the study, our findings provide evidence of the biofilm-modulating ability of QQ and offer novel insights into alternative strategies to restore homeostasis within dysbiotic ecosystems.

Evaluating Alterations of the Oral Microbiome and Its Link to Oral Cancer among Betel Quid Chewers: Prospecting Reversal through Probiotic Intervention

Areca nut and slaked lime, with or without tobacco wrapped in Piper betle leaf, prepared as betel quid, is extensively consumed as a masticatory product in many countries across the world. Betel Quid can promote the malignant transformation of oral lesions as well as trigger benign cellular and molecular changes. In the oral cavity, it causes changes at the compositional level in oral microbiota called dysbiosis. This dysbiosis may play an important role in Oral Cancer in betel quid chewers. The abnormal presence and increase of bacteria Fusobacterium nucleatum, Capnocytophaga gingivalis, Prevotella melaninogenica, Peptostreptococcus sp., Porphyromonas gingivalis, and Streptococcus mitis in saliva and/or other oral sites of the cancer patients has attracted frequent attention for its association with oral cancer development. In the present review, the authors have analysed the literature reports to revisit the oncogenic potential of betel quid and oral microbiome alterations, evaluating the potential of oral microbiota both as a driver and biomarker of oral cancer. The authors have also shared a perspective that the restoration of local microbiota can become a potentially therapeutic or prophylactic strategy for the delay or reversal of lip and oral cavity cancers, especially in high-risk population groups.

Altered oral microbiome in Sudanese Toombak smokeless tobacco users carries a newly emerging risk of squamous cell carcinoma development and progression

There are an estimated 6-10 million smokeless tobacco (Toombak) users in Sudan, the majority being males. Toombak is known to be a carcinogenic product that is likely to modify the oral microbiome spatiality into a high-risk potential for the development and progression of oral cancer, but previous studies are lacking in this field. Here, we endeavour for the first time the exploration of the oral microbiome in key mucosal areas of the oral cavity and assess the microbiome variations in premalignant and oral squamous cell carcinoma (OSCC) samples from both users and non-users of Toombak. 16S rRNA sequencing was performed on DNA obtained from pooled saliva, oral mucosa and supragingival plaque from 78 Sudanese users and non-users of Toombak, aged between 20 and 70 years. In 32 of the pooled saliva samples, the mycobiome (fungal) environment was analysed through ITS sequencing. Then, 46 formalin-fixed paraffin-embedded samples of premalignant and OSCC samples were collected, and their associated microbiomes sequenced. The oral Sudanese microbiome was found to be enriched in Streptococcaceae, but Staphylococcaceae were significantly more abundant amongst Toombak users. Genera enriched in the oral cavity of Toombak users included Corynebacterium_1 and Cardiobacterium while in non-users, Prevotella, Lactobacillus and Bifidobacterium were prominent. Aspergillus was the most abundant fungus in the mouths of Toombak users with a marked loss of Candida. The genus Corynebacterium_1 was abundant in the buccal, floor of the mouth and saliva microbiomes as well as in oral cancer samples from Toombak users indicating a possible role for this genus in the early stages of oral cancer development. An oral cancer microbiome that favours poor survival and metastasis in those who use Toombak also emerged that includes the genera Stenotrophomonas and Schlegelella. Those utilising Toombak carry an altered oral microbiome that may be an additional risk factor for this products carcinogenicity to the oral structures. These significant microbiome modulations are a newly emerging key driving factor in oral cancer development and progression in Toombak users while it is also shown that Toombak users carry an oral cancer microbiome that may increase the potential for a poorer prognosis.

Microencapsulation of Probiotic Streptococcus salivarius LAB813

Probiotics are living microorganisms that confer a health benefit on the host when administered in adequate amounts. Streptococcus salivarius, a commensal bacterium found in the oral cavity, has been shown to secrete antimicrobial peptides and can be used as probiotics. This study aimed to develop a delivery system for the probiotic LAB813, a novel S. salivarius strain first identified in the laboratory. Probiotics can be delivered and protected through the encapsulation of biomaterials such as polysaccharides. Their biocompatibility, biodegradability, user-friendliness, and ease of access make polysaccharides useful for encapsulating probiotics. Alginate (Alg) and chitosan (Ch) are naturally obtained polysaccharides and, hence, tested for LAB813 encapsulation. An extrusion method of encapsulation was performed to form Alg microcapsules (Alg-LAB813), some of which were coated with Ch (Alg-LAB813-Ch) to provide dual-layered protection. Inhibitory assays of the Alg-LAB813 and Alg-LAB813-Ch microcapsules were assayed against an indicator strain. Alg-LAB813-Ch microcapsules showed superior antibacterial properties compared to Alg-LAB813 microcapsules over 24 h and when subject to temperatures ranging from 4 to 68 °C. In addition, Alg-LAB813-Ch microcapsules retained antibacterial activity for up to 28 days of storage at 4 °C. The strong and sustained inhibitory activities of Ch-coated Alg encapsulated LAB813 signify the potential for their use to improve oral health.

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.

Adhesion of Yeast and Bacteria to Oral Surfaces

Colonization of surfaces in the human body by microorganisms is an early, essential, step in the initiation of infectious disease. We have developed in vitro assays to investigate interactions between yeast or bacterial cells and human tissues, fluids, or prostheses. Such assays can be used to identify the adhesins, ligands, and receptors involved in these interactions, for example, by determining which components of the microbe or human tissue/fluid interfere with adherence in the assay. The assays can also be applied to find ways of preventing adhesion, and subsequent disease, by investigating the effects of different conditions and added compounds on adherence in the in vitro assays. Here we describe assays for measuring adhesion of the oral yeast Candida albicans, a common commensal and opportunistic pathogen, or the bacterium Staphylococcus epidermidis, which is not normally pathogenic but is known to form biofilms on medical prostheses. The assays described belong to two approaches to investigating adhesion and biofilm formation: (i) retention at a fixed time point following liquid washes, and (ii) retention against a continuous flow of medium.

Identifying oral microbiome alterations in adult betel quid chewing population of Delhi, India

The study targets to establish a factorial association of oral microbiome alterations (oral dysbiosis) with betel quid chewing habits through a comparison of the oral microbiome of Betel quid chewers and non-chewing individuals. Oral microbiome analysis of 22 adult individuals in the Delhi region of India through the 16S sequencing approach was carried out to observe the differences in taxonomic abundance and diversity. A significant difference in diversity and richness among Betel Quid Chewers (BQC) and Betel Quid Non-Chewers (BQNC) groups was observed. There were significant differences in alpha diversity among the BQC in comparison to BQNC. However, in the age group of 21-30 years old young BQC and BQNC there was no significant difference in alpha diversity. Similar result was obtained while comparing BQC and Smoker-alcoholic BQC. BQ smoker-chewers expressed significant variance in comparison to BQC, based on cluster pattern analysis. The OTU-based Venn Diagram Analysis revealed an altered microbiota, for BQ chewing group with 0-10 years exposure in comparison to those with 10 years and above. The change in the microbial niche in early chewers may be due to abrupt chemical component exposure affecting the oral cavity, and thereafter establishing a unique microenvironment in the long-term BQC. Linear discriminant analysis revealed, 55 significant features among BQC and Alcoholic-Smoker BQC; and 20 significant features among BQC and Smoker BQC respectively. The study shows the abundance of novel bacterial genera in the BQC oral cavity in addition to the commonly found ones. Since the oral microbiome plays a significant role in maintaining local homeostasis, investigating the link between its imbalance in such conditions that are known to have an association with oral diseases including cancers may lead to the identification of specific microbiome-based signatures for its early diagnosis.

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.

Advances in novel therapeutic approaches for periodontal diseases

Periodontal diseases are pathological processes resulting from infections and inflammation affecting the periodontium or the tissue surrounding and supporting the teeth. Pathogenic bacteria living in complex biofilms initiate and perpetuate this disease in susceptible hosts. In some cases, broad-spectrum antibiotic therapy has been a treatment of choice to control bacterial infection. However, increasing antibiotic resistance among periodontal pathogens has become a significant challenge when treating periodontal diseases. Thanks to the improved understanding of the pathogenesis of periodontal disease, which involves the host immune response, and the importance of the human microbiome, the primary goal of periodontal therapy has shifted, in recent years, to the restoration of homeostasis in oral microbiota and its harmonious balance with the host periodontal tissues. This shift in therapeutic goals and the drug resistance challenge call for alternative approaches to antibiotic therapy that indiscriminately eliminate harmful or beneficial bacteria. In this review, we summarize the recent advancement of alternative methods and new compounds that offer promising potential for the treatment and prevention of periodontal disease. Agents that target biofilm formation, bacterial quorum-sensing systems and other virulence factors have been reviewed. New and exciting microbiome approaches, such as oral microbiota replacement therapy and probiotic therapy for periodontal disease, are also discussed.

An In Vitro Evaluation of the Antimicrobial Activity of Probiotics Against Endodontic Pathogens

Background and aim: Despite scientific evidence that even some microorganisms may be useful, endodontic intervention has persisted to prioritize the removal of all microorganisms from the root canal system. Indeed, information regarding the significant role of probiotic microorganisms in endodontic treatment has been sparse. This study aimed to carry out an in vitro evaluation of the antimicrobial activity of probiotics against endodontic pathogens.

Methods: The evaluation was carried out in three stages. In Stage 1, the agar cup well procedure was used to analyse the efficiency of probiotics microorganisms against Enterococcus faecalis bacteria and Candida albicans microorganisms in the planktonic stage. In Stage 2, a deferred antagonistic experiment was used to determine the activity of probiotic microorganisms against endodontic pathogens like E. faecalis and C. albicans in the planktonic phase. In Stage 3, biofilm phase evaluation of an intracanal probiotic microorganism carrier was done. The region of maximum inhibition was measured at the end of Stages 1 and 2. The antimicrobial activity was recognized when the dimension of the region of maximum inhibition was 10 mm or above. The colony-forming unit/millilitre was measured at the end of Stage 3.

Results: There was marked antimicrobial activity of probiotic microorganisms against the pathogenic microorganisms E. faecalis as well as C. albicans in Stages 1 and 3, i.e., during the evaluation involving agar cup and evaluation at the biofilm stage. However, no antimicrobial activity of probiotic microorganisms was observed against pathogenic endodontic microorganisms in Stage 2, i.e., during evaluation involving the use of the deferred antagonistic technique.

Conclusion: It can be concluded that probiotic therapy is a promising antibacterial treatment approach that should be further investigated. This study shows that probiotics can help effectively in endodontic treatment and that more in vitro as well as in vivo research is needed to fully appreciate the advantages of bacteriotherapy in the field of endodontics.

Influence of probiotics on the periodontium, the oral microbiota and the immune response during orthodontic treatment in adolescent and adult patients (ProMB Trial): study protocol for a prospective, double-blind, controlled, randomized clinical trial

Background

Orthodontic treatment with fixed appliances is often necessary to correct malocclusions in adolescence or adulthood. However, oral hygiene is complicated by appliances, and prior studies indicate that they may trigger oral inflammation and dysbiosis of the oral microbiota, especially during the first 3 months after insertion, and, thus, may present a risk for inflammatory oral diseases. In recent periodontal therapeutic studies, probiotics have been applied to improve clinical parameters and reduce local inflammation. However, limited knowledge exists concerning the effects of probiotics in orthodontics. Therefore, the aim of our study is to evaluate the impact of probiotics during orthodontic treatment.

Methods

This study is a monocentric, randomized, double blind, controlled clinical study to investigate the effectiveness of daily adjuvant use of Limosilactobacillus reuteri (Prodentis®-lozenges, DSM 17938, ATCC PTA 5289) versus control lozenges during the first three months of orthodontic treatment with fixed appliances. Following power analysis, a total of 34 adolescent patients (age 12–17) and 34 adult patients (18 years and older) undergoing orthodontic treatment at the University Hospital Erlangen will be assigned into 2 parallel groups using a randomization plan for each age group. The primary outcome measure is the change of the gingival index after 4 weeks. Secondary outcomes include the probing pocket depth, the modified plaque index, the composition of the oral microbiota, the local cytokine expression and—only for adults—serum cytokine levels and the frequencies of cells of the innate and adaptive immune system in peripheral blood.

Discussion

Preventive strategies in everyday orthodontic practice include oral hygiene instructions and regular dental cleaning. Innovative methods, like adjuvant use of oral probiotics, are missing. The aim of this study is to analyse, whether probiotics can improve clinical parameters, reduce inflammation and prevent dysbiosis of the oral microbiota during orthodontic treatment. If successful, this study will provide the basis for a new strategy of prophylaxis of oral dysbiosis-related diseases during treatment with fixed appliances.

Trial registration

This trial is registered at ClinicalTrials.gov in two parts under the number NCT04598633 (Adolescents, registration date 10/22/2020), and NCT04606186 (Adults, registration date 10/28/2020).

Short- term effect of probiotic Lactobacillus reuteri consumption on the salivary microbiome profile of subjects undergoing orthodontic treatment with fixed appliances

Objective

Methods

Results

Conclusion

Lactobacillus plantarum Disrupts S. mutans–C. albicans Cross-Kingdom Biofilms

Dental caries, an ecological dysbiosis of oral microflora, initiates from the virulent biofilms formed on tooth surfaces where cariogenic microorganisms metabolize dietary carbohydrates, producing acid that demineralizes tooth enamel. Forming cariogenic biofilms, Streptococcus mutans and Candida albicans are well-recognized and emerging pathogens for dental caries. Recently, probiotics have demonstrated their potential in treating biofilm-related diseases, including caries. However, limited studies have assessed their effect on cariogenic bacteria–fungi cross-kingdom biofilm formation and their underlying interactions. Here, we assessed the effect of four probiotic Lactobacillus strains (Lactobacillus rhamnosus ATCC 2836, Lactobacillus plantarum ATCC 8014, Lactobacillus plantarum ATCC 14917, and Lactobacillus salivarius ATCC 11741) on S. mutans and C. albicans using a comprehensive multispecies biofilm model that mimicked high caries risk clinical conditions. Among the tested probiotic species, L. plantarum demonstrated superior inhibition on the growth of C. albicans and S. mutans, disruption of virulent biofilm formation with reduced bacteria and exopolysaccharide (EPS) components, and formation of virulent microcolonies structures. Transcriptome analysis (RNA sequencing) further revealed disruption of S. mutans and C. albicans cross-kingdom interactions with added L. plantarum. Genes of S. mutans and C. albicans involved in metabolic pathways (e.g., EPS formation, carbohydrate metabolism, glycan biosynthesis, and metabolism) were significantly downregulated. More significantly, genes related to C. albicans resistance to antifungal medication (ERG4), fungal cell wall chitin remodeling (CHT2), and resistance to oxidative stress (CAT1) were also significantly downregulated. In contrast, Lactobacillus genes plnD, plnG, and plnN that contribute to antimicrobial peptide plantaricin production were significantly upregulated. Our novel study findings support further assessment of the potential role of probiotic L. plantarum for cariogenic biofilm control.

Clinical Effects of Locally Delivered Lactobacillus reuteri as Adjunctive Therapy in Patients with Periodontitis: A Split-Mouth Study

Different methods and products have been investigated as measures of adjunctive therapy to scaling and root planing (SRP). Probiotic use has gained interest for this particular application, especially Lactobacillus spp. This split-mouth interventional prospective study aimed to evaluate the clinical effects of L. reuteri DSM 17938 with local application in periodontal pockets of severe periodontitis patients. The study was conducted on 40 subjects with stage 3–4 periodontitis who, based on a split-mouth model, followed SRP and SRP + L. reuteri solution in five weekly sessions. Probing depth (PD), clinical attachment loss (CAL), and bleeding on probing (BOP) were assessed at baseline and at three months after probiotic treatment completion. Both SRP and SRP + L. reuteri generated significant improvements of all three clinical parameters, but the changes were significantly better for SRP + L. reuteri treated sites. Therefore, we can conclude that adjunctive therapy with L. reuteri DSM 17938 could represent an interesting treatment option, particularly for severe periodontitis cases.

Effect of Lactobacillus reuteri on Gingival Inflammation and Composition of the Oral Microbiota in Patients Undergoing Treatment with Fixed Orthodontic Appliances: Study Protocol of a Randomized Control Trial

The effect of probiotics in improving or maintaining oral health in orthodontic patients is understudied. The aim of this study is to evaluate the effect of probiotic administration in addition to tooth brushing on clinical gingival inflammation, plaque formation, subgingival microbiota composition, and salivary biomarkers of inflammation in adolescents with fixed orthodontic appliances. The present study is a 6-month, double-blind, two-arm, placebo-controlled, single-center trial, in which 116 adolescent volunteers aged 12-16 years will be recruited from the patients of the orthodontics clinic of the University Hospital of Lille, France. Subjects who meet the eligibility criteria will be allocated to one of the following groups: (i) control: two placebo lozenges per day for 90 days together with regular oral hygiene, (ii) test: two probiotic lozenges per day for 90 days together with regular oral hygiene. Clinical assessment and biological sample collection will be performed at baseline, 3 and 6 months. In addition, compliance outcomes and adverse events will be monitored.

Investigation and comparison of the effects of two probiotic bacteria, and in reducing mutans streptococci levels in the saliva of children

Background

Probiotic organisms Lactobacillus reuteri UBLRU-87 and Bifidobacterium bifidum UBBB-55 were proven to be acting against the caries causing organisms.

Aims

This study aims to evaluate the influence of Lactobacillusreuteri, Bifidobacterium bifidum and their blend on Mutans streptococci count in the saliva of children, and also to appraise the sustainability of their action.

Materials and Methods

A randomized, double-blind and placebo-controlled study with 60 subjects (15 in each group) in 6-14 years of age group. The children consumed curd containing Bifidobacterium bifidum (UBBB 55, MTCC 5398) and Lactobacillus reuteri (UBLRu 87, MTCC 5403), and their blend once daily for 14 days. The control group received curd with no Probiotic in it. The saliva samples were collected just before the curd (T0) administration to establish baseline levels of mutans streptococci and after a day of the final consumption of the curd (T14). The follow-up samples at 21 days (T21) and 28 days (T28) after the baseline were also collected to know the sustainability of action probiotics on mutans streptococci if any.

Results

Statistically significant reduction of mutans streptococci is observed in the group administered with Lactobacillus reuteri and the effect lasted up to a minimum of 21 days. Mixed cultures are seemed to be not effective against the oral microorganisms.

Conclusions

The probiotic organism Lactobacillus reuteri in Indian curd is effective on salivary mutans streptococci, and the effect was sustained for some period after the administration.

The Oral-Microbiome-Brain Axis and Neuropsychiatric Disorders: An Anthropological Perspective

In the 21st century, neuropsychiatric disorders (NPDs) are on the rise, yet the causal mechanisms behind this global epidemic remain poorly understood. A key to these unknowns may lie within the vast communities of bacteria, fungi, and viruses in the body (microbiota), which are intimately linked with health and disease. NPDs were recently shown to be connected to gut microbiota, which can communicate with and influence the brain through the Gut-Brain-Axis (GBA). Parallel studies examining oral microbiota and their connections to the brain also suggest that microbes in the mouth can similarly influence NPD outcomes. However, the mechanisms and pathways that illuminate how oral microbiota and brain communicate in NPDs remain unknown. Here, we review identified mechanisms and pathways that oral microbiota use to engage the brain, and we lay the theoretical foundation for an oral-microbiota-brain axis (OMBA). Specifically, we examine established neuroinflammatory and immune system activation responses that underpin interactions between the oral microbiota and the central nervous system (CNS), detailing four specific mechanisms: (1) microbial and metabolite escape, (2) neuroinflammation, (3) CNS signaling, and (4) response to neurohormones. We then scrutinize why including the OMBA, in addition to the GBA, is critically needed to elucidate specific causal relationships between microbial dysbiosis and observed NPD development and progression. Furthermore, we argue for comprehensive, interdisciplinary approaches that integrate lab-based microbiome research and population-level studies that examine the OMBA to improve NPDs. We specifically identify key anthropological perspectives that integrate sociocultural, epidemiological, genetic, and environmental factors that shape the oral microbiome and its interactions with NPDs. Together, future studies of the OMBA in conjunction with interdisciplinary approaches can be used to identify NPD risks and improve outcomes, as well as develop novel intervention and treatment strategies.

Classic vs. Novel Antibacterial Approaches for Eradicating Dental Biofilm as Adjunct to Periodontal Debridement: An Evidence-Based Overview

Periodontitis is a multifactorial chronic inflammatory disease that affects tooth-supporting soft/hard tissues of the dentition. The dental plaque biofilm is considered as a primary etiological factor in susceptible patients; however, other factors contribute to progression, such as diabetes and smoking. Current management utilizes mechanical biofilm removal as the gold standard of treatment. Antibacterial agents might be indicated in certain conditions as an adjunct to this mechanical approach. However, in view of the growing concern about bacterial resistance, alternative approaches have been investigated. Currently, a range of antimicrobial agents and protocols have been used in clinical management, but these remain largely non-validated. This review aimed to evaluate the efficacy of adjunctive antibiotic use in periodontal management and to compare them to recently suggested alternatives. Evidence from in vitro, observational and clinical trial studies suggests efficacy in the use of adjunctive antimicrobials in patients with grade C periodontitis of young age or where the associated risk factors are inconsistent with the amount of bone loss present. Meanwhile, alternative approaches such as photodynamic therapy, bacteriophage therapy and probiotics showed limited supportive evidence, and more studies are warranted to validate their efficiency.

Orodispersible films: Conception to quality by design

Orodispersible films (ODFs) are ultra-thin, stamp-sized, elegant, portable and patient-centric pharmaceutical dosage forms that do not need water to be ingested. They are particularly useful for paediatric and geriatric patient populations with special needs such as dysphagia, Parkinson's disease, and oral cancer. Accordingly, they hold tremendous potential in gaining patient compliance, convenience and pharmacotherapy. In the present review, conception and evolution of ODFs as a product and its technology are discussed. The review continues by providing overview about the potential of ODFs as carriers for delivering drugs, herbal extracts, probiotics and vaccines. Besides, strategies employed in drug cargo loading, taste masking of bitter drugs and enhancing drug stability are discussed. Finally, the review concludes by providing a brief overview about quality by design (QbD) principles in development of ODFs.

A comparative evaluation of probiotic formulations in prevention of dental caries: A clinical study

BACKGROUND

Caries is a multifactorial disease, microbes being an important etiological factor. "Probiotics" are nonpathogenic microbes which can stimulate health-promoting flora and suppress pathogens. It's the era of prevention, clinical approach toward prevention by altering bacterial ecology is the need of the hour. The aim of the study was to evaluate anticariogenic effect of probiotic curd (Amul's Probiotic Dahi) containing Lactobacillus acidophilus (La5) and Bifidobacterium lactis (Bb12) in 6-12 years of age group.

MATERIALS AND METHODS

This was a prospective, randomized, nonblinded study conducted on school children aged between 6 and 12 years having Decayed, Missing, and Filled Teeth and/or deft ≥2. Selected subjects were divided into two groups of 31 each, study group received probiotic curd ("Amul's Probiotic Dahi") two times a day in a quantity of 100 g, respectively, for 21 days and control group did not receive any intervention. Salivary Streptococcus mutans count and salivary pH estimation were done at the baseline, after 7 days and at the end after 24 days, for comparison.

RESULTS

No statistical difference was seen in salivary S. mutans count between both groups, after intervention of 7 days. However, there was significant difference in salivary S. mutans count at the end of 24 days. There was no statistical difference in salivary pH between both groups.

CONCLUSION

The present study concludes that probiotics substitute decreases salivary S. mutans count after continuous consumption for 3 weeks and there is no short-term effect on salivary pH.

Should local drug delivery systems be used in dentistry?

In dentistry, the use of biomaterial-based drug delivery systems (DDS) aiming the release of the active compounds directly to the site of action is slowly getting more awareness among the scientific and medical community. Emerging technologies including nanotechnological platforms are offering novel approaches, but the majority are still in the proof-of-concept stage. This study critically reviews the potential use of DDS in anesthesiology, oral diseases, cariology, restorative dentistry, periodontics, endodontics, implantology, fixed and removable prosthodontics, and orthodontics with a special focus on infections. It also stresses the gaps and challenges faced. Despite numerous clinical and pharmacological advantages, some disadvantages of DDS pose an obstacle to their widespread use. The biomaterial's biofunctionality may be affected when the drug is incorporated and may cause an additional risk of toxicity. Also, the release of sub-therapeutic levels of drugs such as antibiotics may lead to microbial resistance. Multiple available techniques for the manufacture of DDS may affect drug release profiles and their bioavailability. If the benefits outweigh the costs, DDS may be potentially used to prevent or treat oral pathologies as an alternative to conventional strategies. A case-by-case approach must be followed.

A Review of the Role of Probiotic Supplementation in Dental Caries

Dental diseases are among the common health issues experienced around the world. Dental caries is one of the most predominant oral diseases worldwide. Major factors associated with caries development include poor oral hygiene, the content of specific carbohydrates in the diet, dental biofilm formation, the cariogenic microbial load, reduction in salivary flow, insufficient fluoride exposure, gingival recession, genetic factors, and lack of personal attention to one's dental health. Several preventive measures have been implemented to reduce the risk of the development of caries. Probiotics are live microbes that when administered in suitable amounts confer health benefits on the host; they are recognized as potential adjunct therapeutic agents for several diseases. The present manuscript summarizes recent findings on the role of probiotics in dental caries prevention and the possible mechanisms of probiotic effects. Review of the literature indicates the regular consumption of probiotic products significantly reduced the risk of caries by inhibiting cariogenic bacteria and enriching commensal microbes in the oral cavity. Buffering the salivary pH, production of bacteriocin and enzymes (dextranase, mutanase, and urease), the capacity of competing for the adhesion and colonization on tooth surfaces are the possible mechanisms behind the beneficial effect of probiotics. Further studies are necessary to address the efficacy of long-term probiotic supplementation on the control of dental diseases and the influence of childhood probiotic supplementation on the risk of caries development.

CLINICAL EFFICACY OF PROBIOTICS AS AN ADJUNCTIVE THERAPY TO SCALING AND ROOT PLANNING IN THE MANAGEMENT OF PERIODONTITIS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED CONTROLLED TRAILS

OBJECTIVES

To evaluate the efficacy of probiotics as an adjunctive therapy to scaling and root planning treatment (SRP) in the management of periodontitis.

METHODS

PubMed, Embase, Web of science, SCOPUS and the Cochrane library were systematically searched to identify eligible studies. Stata 12.0 software was used to calculate the weighted mean differences (WMD) and 95% confidential interval (CI). The primary outcomes were clinical attachment level (CAL), probing pocket depth (PPD) and bleeding on probing (BOP).

RESULTS

Twenty-four randomized controlled trials (RCT) were included in the meta-analysis. The pooled results showed CAL gain (WMD: 0.20, 95% CI 0.09 to 0.31), PPD reduction (WMD: -0.31, 95% CI -0.52 to -0.10) and BOP reduction (WMD: -2.98, 95% CI -4.70 to -1.26) in the SRP+ probiotics group were significantly improved compared to control group at 3 months follow-up, but no significant difference was observed at 6 months. In addition, the probiotics administration could improve Plaque index (WMD: -0.30, 95% CI -0.59 to -0.05) and Gingival index (WMD: -0.46, 95% CI -0.71 to -0.21) at short term.

CONCLUSIONS

The results support the clinical efficacy of probiotics as an adjunctive therapy to SRP in the management of periodontitis at least 3 months follow-up. Within the limits of the evidence, the long-term efficacy needs to further confirm.

Probiotic therapy for periodontal and peri-implant health - silver bullet or sham?

Probiotics are thought to be beneficial microbes that influence health-related outcomes through host immunomodulation and modulation of the bacteriome. Its reported success in the treatment of gastrointestinal disorders has led to further research on its potential applicability within the dental field due to similarities such as a polymicrobial aetiology and disease associated microbial-shifts. Although the literature is replete with studies demonstrating its efficacy, the use of probiotics in dentistry continues to polarise opinion. Here, we explore the evidence for probiotics and its effect on periodontal and peri-implant health. MEDLINE, EMBASE, and CENTRAL were systemically searched from June 2010 to June 2020 based on a formulated search strategy. Of 1,956 potentially relevant articles, we selected 27 double-blinded randomised clinical trials in the areas of gingivitis, periodontitis, residual pockets during supportive periodontal therapy, and peri-implant diseases, and reviewed their efficacy in these clinical situations. We observed substantial variation in treatment results and protocols between studies. Overall, the evidence for probiotic therapy for periodontal and peri-implant health appears unconvincing. The scarcity of trials with adequate power and follow-up precludes any meaningful clinical recommendations. Thus, the routine use of probiotics for these purposes are currently unsubstantiated. Further multi-centre trials encompassing a standardised investigation on the most promising strains and administration methods, with longer observation times are required to confirm the benefits of probiotic therapy for these applications.

Inhibitory effects of Lactobacillus brevis KU15153 against Streptococcus mutans KCTC 5316 causing dental caries

This study determined the inhibitory effect of Lactobacillus brevis KU15153 against cariogenic Streptococcus mutans KCTC 5316. Antimicrobial activity, auto-aggregation, cell surface hydrophobicity, exopolysaccharides (EPS) production, biofilm formation, and morphological changes were assessed in the presence of L. brevis KU15153. L. brevis KU15153 exhibited the highest antimicrobial activity against S. mutans KCTC 5316 (28.67 ± 4.16 mm). Auto-aggregation (38.32%), cell surface hydrophobicity (27.08%), and EPS production rate (58.52%) of S. mutans KCTC 5316 slightly decreased upon treatment with L. brevis KU15153. Additionally, crystal violet stanning and scanning electron microscopy confirmed the L. brevis KU15153-mediated inhibition of biofilm formation by S. mutans KCTC 5316 in comparison to that observed in the negative control (untreated S. mutans KCTC 5316). These results indicate that the L. brevis KU15153 could be used as a potential probiotic for maintaining oral health.

Milk Kefir therapy reduces inflammation and alveolar bone loss on periodontitis in rats

Periodontitis is a chronic inflammatory disease that affects the tooth-supporting tissues. This study evaluated the anti-inflammatory and antiresorptive effects of milk kefir (MK) on periodontitis in rats. Micro-Raman spectroscopy was performed on MK at different fermentation times to verify the presence of Lactobacillus kefiri. From these results, Wistar rats were divided into the following groups: C (Control); EP (experimental periodontitis); K1 (animals that received MK with one day of fermentation); K1+EP; K4 (animals without EP using MK with four days of fermentation) and K4+EP. MK was administered 28 days before EP induction and during the disease development period (11 days). On day 28, in the EP groups, periodontitis was induced. The animals were euthanized on day 39. The hemimaxillae were removed and the following parameters were evaluated: micro-Raman analysis of the presence of inflammation; histomorphometric analysis to quantify alveolar bone loss and immunohistochemistry for IL-6, TNF-α, IL-Iβ and IL-10 in the periodontal ligament. Micro-Raman analysis showed that four days fermentation MK has a higher intensity spectrum of L. kefiri. Furthermore, the administration of this probiotic reduced the intensity of the inflammation spectrum when compared to one day fermentation MK. It was observed that the animals from the K4+EP group showed significant reduction of alveolar bone loss, as well as a lower IL-6, TNF-α and IL-Iβ immunoexpression and a higher IL-10 immunoexpression, when compared to EP groups. We conclude that MK has anti-inflammatory and antiresorptive effects on periodontitis in rats and that these effects are fermentation time dependent.

Histone Deacetylase Modifications by Probiotics in Colorectal Cancer

It has been demonstrated that epigenetic modifications of histone (acetylation/deacetylation) participate in a critical role in cancer progression by the regulation of gene expression. Several processes could be regulated by deacetylation of histone and non-histone proteins such as apoptosis, proliferation, cell metabolism, differentiation, and DNA repair. Hence, histone deacetylase inhibitors (HDACis) are employed as a hopeful group of anti-cancer drugs that could inhibit tumor cell proliferation or apoptosis. The elimination of the acetylation marks that take place as an essential epigenetic change in cancer cells is associated to HDAC expression and activity. In this regard, it has been reported that class I HDACs have a vital role in the regulation of tumor cell proliferation. OBJECTIVES: In this review, we discuss whether gut origin microorganisms could promote cancer or tumor resistance and explain mechanisms of these processes. CONCLUSIONS: According to the enormous capacity of the metabolism of the intestine microbiota, bacteria are likely to convert nutrients and digestive compounds into metabolites that regulate epigenetic in cancer. The effect of the food is of interest on epigenetic changes in the intestinal mucosa and colonocytes, as misleading nucleotide methylation may be a prognostic marker for colorectal cancer (CRC). Since epigenetic changes are potentially reversible, they can serve as therapeutic targets for preventing CRC. However, various mechanisms have been identified in the field of prevention, treatment, and progression of cancer by probiotics, which include intestinal microbiota modulation, increased intestinal barrier function, degradation of potential carcinogens, protective effect on intestinal epithelial damage, and increased immune function.

Comparative evaluation of different probiotic products on salivary Streptococcus mutans and Lactobacillus level in caries risk population

Introduction

Dental caries is a multifactorial disease with the main causative organism being Streptococcus mutans and Lactobacillus spp. "Probiotics" are defined as living microorganisms, principally bacteria, which are safe for human consumption and when ingested in sufficient quantities, have beneficial effects on human health, beyond basic nutrition. These can be used to replace the pathogenic strains of bacteria with the nonpathogenic type in the oral cavity thus can help prevent dental caries.

Aims

To evaluate and compare the role of probiotic milk and lozenges on S. mutans and Lactobacillus spp. count on patients who are exposed to probiotics continuously for 7 days.

Materials and Methods

Sixty volunteers who were prone to caries were divided into three equal groups. Experimental groups were given probiotics daily for 7 days. In Group A, patients were given milk without any probiotics (control); in Group B, probiotic milk is given; and in Group C, probiotic lozenges are given. Saliva samples were assessed on the 1^st day and after 7 days of intervention. The collected saliva samples were inoculated on the selected culture media and estimation was done by measuring the colony-forming unit.

Statistical Analysis Used

Statistical analysis was performed using Student's paired t-test and multiple comparisons by Tukey's honest significant difference test.

Results

There was a significant reduction in salivary S. mutans level in both experimental groups after 7 days (P < 0.05). However, there was no significant difference in Lactobacillus count before and after the intervention.

Conclusions

Probiotics have a role in reducing salivary S. mutans count. Probiotics lozenges showed greater efficacy in reducing salivary S. mutans count than probiotic milk.

Focal Infection and Periodontitis: A Narrative Report and New Possible Approaches

The "focal infection theory" is a historical concept based on the assumption that some infections may cause chronic and acute diseases in different districts of the body. Its great popularity spanned from 1930 to 1950 when, with the aim to remove all the foci of infection, drastic surgical interventions were performed. Periodontitis, a common oral pathology mainly of bacterial origin, is the most evident example of this phenomenon today: in fact, bacteria are able to migrate, develop and cause health problems such as cardiovascular and respiratory diseases, diabetes, and osteoporosis. The aim of this narrative report is to verify the hypothesis of the association between oral infections and systemic diseases by different ways of approach and, at the same time, to propose new kinds of treatment today made possible by technological progress. The analysis of the literature demonstrated a strong relationship between these conditions, which might be explained on the basis of the recent studies on microbiota movement inside the body. Prevention of the oral infections, as well as of the possible systemic implications, may be successfully performed with the help of new technologies, such as probiotics and laser.

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.

Probiotic Effects on Multispecies Biofilm Composition, Architecture, and Caries Activity In Vitro

While probiotics have been tested for their anti-caries effect in vitro and also clinically, there is a lack of understanding of their effects on complex dental biofilms. We assessed two probiotics, Lactobacillus reuteri and Streptococcus oligofermentans, on a continuous-cultured model containing Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces naeslundii. Cariogenic biofilms were grown on bovine enamel specimens and daily challenged with L. reuteri or S. oligofermentans whole culture (LC/SC) or cell-free supernatant (LS/SS) or medium only (negative control, NC) (n = 21/group) for 10 days. Biofilm was assessed via counting colony-forming units, quantitative polymerase chain reaction, and fluorescence in situ hybridization. Caries activity was determined by pH measurements and by assessing mineral loss (ΔZ) using transverse microradiography. Both LC and SC significantly reduced total and strain-specific cariogenic bacterial numbers (p < 0.05). ΔZ was reduced in LC (mean ± SD: 1846.67 ± 317.89) and SC (3315.87 ± 617.30) compared to NC (4681.48 ± 495.18, p < 0.05). No significant reductions in bacterial numbers and ΔZ was induced by supernatants. Biofilm architecture was not considerably affected by probiotic applications. Viable probiotics L. reuteri and S. oligofermentans, but not their culture supernatants, could reduce the caries activity of multi-species biofilms in vitro.

Environment-Specific Probiotic Supernatants Modify the Metabolic Activity and Survival of Streptococcus mutans in vitro

A range of studies showed probiotics like Streptococcus oligofermentans and Limosilactobacillus reuteri to inhibit the cariogenic activity and survival of Streptococcus mutans, possibly via the production of substances like H₂O₂, reuterin, ammonia and organic acids. We aimed to assess the environment-specific mechanisms underlying this inhibition. We cultured L. reuteri and S. oligofermentans in various environments; minimal medium (MM), MM containing glucose (MM+Glu), glycerol (MM+Gly), lactic acid (MM+Lac), arginine (MM+Arg) and all four substances (MM+all) in vitro. Culture supernatants were obtained and metabolite concentrations (reuterin, ammonia, H₂O₂, lactate) measured. S. mutans was similarly cultivated in the above six different MM variation media, with glucose being additionally added to the MM+Gly, MM+Lac, and MM+Arg group, with (test groups) and without (control groups) the addition of the supernatants of the described probiotic cultures. Lactate production by S. mutans was measured and its survival (as colony-forming-units/mL) assessed. L. reuteri environment-specifically produced reuterin, H₂O₂, ammonia and lactate, as did S. oligofermentans. When cultured in S. oligofermentans supernatants, lactate production by S. mutans was significantly reduced (p < 0.01), especially in MM+Lac+Glu and MM+all, with no detectable lactate production at all (controls means ± SD: 4.46 ± 0.41 mM and 6.00 ± 0.29 mM, respectively, p < 0.001). A similar reduction in lactate production was found when S. mutans was cultured in L. reuteri supernatants (p < 0.05) for all groups except MM+Lac+Glu. Survival of S. mutans cultured in S. oligofermentans supernatants in MM+Lac+Glu and MM+all was significantly reduced by 0.6-log₁₀ and 0.5-log₁₀, respectively. Treatment with the supernatant of L. reuteri resulted in a reduction in the viability of S. mutans in MM+Gly+Glu and MM+all by 6.1-log₁₀ and 7.1-log₁₀, respectively. Probiotic effects on the metabolic activity and survival of S. mutans were environment-specific through different pathways.

Do probiotics promote oral health during orthodontic treatment with fixed appliances? A systematic review

BACKGROUND

Treatment with fixed orthodontic appliances has been associated with significant biofilm accumulation, thus putting patients at a higher risk of oral health deterioration. The use of probiotics has been proposed to be useful in the prevention or treatment of oral pathologies such as caries and diseases of periodontal tissues. Our aim was to investigate the effects of probiotic use on inflammation of the gingival tissues and the decalcification of the enamel in patients being treated with fixed orthodontic appliances.

METHODS

We searched without restrictions 8 databases and performed hand searching until September 2019. We searched for randomized controlled trials (RCTs) evaluating whether individuals with fixed orthodontic appliances benefit from probiotic treatment in terms of the inflammation of the gingivae and decalcification of the enamel. Following the selection of studies and the extraction of pertinent data, we appraised the risk of bias and the confidence in the observed effects based on established methodologies.

RESULTS

From the final qualifying studies, three did not show any statistically significant effect on gingival inflammation after probiotic administration of up to 1 month. Similarly, non-significant differences were noted in another study regarding white spot lesions development (mean administration for 17 months). No adverse effects were reported and the level of evidence was considered moderate.

CONCLUSIONS

Supplementation of orthodontic patients with probiotics did not affect the development of inflammation in the gingivae and decalcification in the enamel. Additional RCTs, with longer intervention and follow-up periods, and involving different combinations of probiotic strains are required.

TRIAL REGISTRATION

PROSPERO (CRD42018118008).

Mucoadhesive Buccal Films for Local Delivery of Lactobacillus brevis

The aim of this work was to prepare mucoadhesive buccal films for local release of Lactobacillus brevis CD2, which shows interesting anti-inflammatory properties due to its high levels of arginine deiminase. Hydroxypropylmethylcellulose-based films were prepared by means of a modified casting method, which allowed L. brevis CD2 loading on one side of the film, before its complete drying. Three batches of films were prepared, stored at +2-8 °C and +23-25 °C for 48 weeks and characterized in terms of physico-chemical and functional properties. For each batch, the L. brevis viable count and arginine deiminase activity were evaluated at different time points in order to assess functional property maintenance over time. Moreover, the mucoadhesive properties and ability of the films to release L. brevis CD2 were evaluated. A good survival of L. brevis CD2 was observed, particularly at the storage temperature of +2-8 °C, while the activity of arginine deiminase was maintained at both temperature values. Films showed good mucoadhesive properties and guaranteed a prolonged release of viable lactobacilli, which can be directed towards the whole buccal cavity or specific mucosa lesions. In conclusion, the proposed preparative method can be successfully employed for the production of buccal films able to release viable L. brevis CD2 cells that maintain the anti-inflammatory enzymatic activity.

In vitro inhibitory effect of two commercial probiotics on chromogenic actinomycetes

PURPOSE

Black extrinsic discoloration is a common clinical and aesthetic problem. This study aims to evaluate the potential in vitro antagonistic activity of two commercial probiotics, Streptococcus salivarius M18 and Lactobacillus reuteri ProDentis, against microorganisms associated with black stains.

METHODS

Streptococcus salivarius M18 and Lactobacillus reuteri were tested against Aggregatibacter actinomycetemcomitans and Actinomyces naeslundiiusing their cell-free fermentative broth in a planktonic growth inhibition test.

RESULTS

Both probiotic cell-free supernatants showed the ability to reduce the pathogenic bacteria growth in a dose-dependent way. Streptococcus salivarius M18 showed a stronger antimicrobial activity than Lactobacillus reuteri ProDentis against the two indicator strains used. A. naeslundi was less susceptible to the probiotic activity of both S. salivarius and L. reuteri compared to A. actinomycetemcomitans.

CONCLUSIONS

The obtained results demonstrate a potent antagonistic ability of probiotics to reduce the growth of microorganisms associated with black tooth stains. Therefore, these strains could be evaluated for a therapeutic use against dental pigmentations.

Application of Antibiotics/Antimicrobial Agents on Dental Caries

Dental caries is the most common oral disease. The bacteriological aetiology of dental caries promotes the use of antibiotics or antimicrobial agents to prevent this type of oral infectious disease. Antibiotics have been developed for more than 80 years since Fleming discovered penicillin in 1928, and systemic antibiotics have been used to treat dental caries for a long time. However, new types of antimicrobial agents have been developed to fight against dental caries. The purpose of this review is to focus on the application of systemic antibiotics and other antimicrobial agents with respect to their clinical use to date, including the history of their development, and their side effects, uses, structure types, and molecular mechanisms to promote a better understanding of the importance of microbial interactions in dental plaque and combinational treatments.

Khat Chewing Induces a Floral Shift in Dental Material-Associated Microbiota: A Preliminary Study

Background

The habit of khat (Catha Edulis Forskal) chewing is widely practiced in the southern regions of Saudi Arabia, Yemen, and East Africa. This social habit has tremendous effects on oral and general health of khat chewers. Khat may affect bacterial species in plaque biofilms on oral rehabilitation materials. This preliminary case-controlled study aimed to assess and compare the effect of khat chewing on bacterial biodiversity between non-khat chewers (NKC) and khat chewers (KC) in oral biofilms on oral rehabilitation materials using polymerase chain reaction (PCR).

Material/Methods

Fifty participants were organized into 2 equal groups of NKC and KC, each containing 5 subgroups related to filling material type. Some participants had amalgam (A) or composite (C) restorations, while others had feldspathic porcelain (FP), nickel chromium (NC), and zirconia ceramic (ZC) crowns or bridges. Oral biofilm samples were collected from all participants, DNA was extracted, and samples were subjected to PCR. Bacterial species were then identified and counted. PCR products were sequenced to detect similarity. Partial 16S rRNA gene sequences of the current study samples were compared with 16S rRNA gene sequences from GenBank using BLAST on the National Center for Biotechnology Information website.

Results

The Streptococcus sp. was the most common bacterial species among our participants (40; 80%), followed by Lactobacillus and Veillonella spp., accounting for 12% (6) and 8% (4), respectively. Streptococcus sp. was observed equally among NKC and KC, but Lactobacillus and Veillonella spp. were higher in KC and NKC, respectively. Lactobacillus was associated mainly with prosthetic materials, and Streptococcus was found among all examined dental restorative materials.

Conclusions

This research concluded that khat chewing significantly affects bacterial biodiversity in oral biofilms in the presence of different restorative and prosthetic dental materials.

Antimicrobial activity of probiotics against endodontic pathogens:- A preliminary study

Introduction

The purpose of this study was to evaluate the antibacterial effectiveness of probiotics lactobacilli group and Bifidobacterium against Enterococcus faecalis and Candida albicans in both planktonic stage and biofilm stage.

Materials and Methods

Phase 1 of the study was conducted by agar well diffusion method. About 0.5 ml of test pathogen culture was inoculated on 20 ml of molten agar and allowed to solidify. 4-5 circular wells of diameter 8-10 mm were punched in each poured plates and 150 μl of diluted test samples were added to the wells. Phase 2 was deferred antagonism test, wherein purified culture of pathogen strain was streaked at right angle to the original producer growth and incubated at 37°C for 24 h. Zone of inhibition was measured for both the phases. Phase 3 biofilm stage evaluation was conducted by mixing 9 ml of 30% poloxamer 407 and De Man, Rogosa and Sharpe (MRS) broth in a test tube with 500 μl of either pathogen, together with 500 μl of test probiotic strains and incubated (37°C, 48 h), followed by serially diluting the mixture by 1 ml into 9 ml sterile saline till 10⁸ dilutions for evaluation of colony-forming unit/ml counts. Controls were endodontic pathogens in 30% poloxamer with MRS broth and no probiotics.

Results

Results were evaluated and statistically analysed using one-way analysis of variance and unpaired t-test. In the planktonic stage, probiotics showed inhibitory activity against endodontic pathogens with valid statistical significance (P < 0.05), while there was no activity by deferred antagonism method. In biofilm stage, all three probiotics showed growth reduction for E. faecalis, while lactobacilli group showed reduction in C. albicans colonies.

Conclusion

This preliminary study suggested that probiotics are effective for preventing the growth of endodontic pathogens in vitro. Poloxamer could be utilised as an ideal delivery vehicle for probiotics.

Comparing the Effectiveness of Probiotic, Green Tea, and Chlorhexidine- and Fluoride-containing Dentifrices on Oral Microbial Flora: A Double-blind, Randomized Clinical Trial

Introduction:

Oral cavity harbors wide variety of microorganisms; these are considered crucial for the dental caries initiation and progression. Plaque-induced caries is a local disease; therefore, dentifrices are the most ideal vehicle for the daily delivery of antibacterial agents. In recent years, alternatives to fluorides such as green tea, probiotic, and chlorhexidine (CHX) toothpastes have been proposed to possess antiplaque and anticariogenic properties.

Aim:

To compare the effectiveness of probiotic, green tea, and CHX- and fluoride-containing dentifrices on oral microbial flora.

Materials and Methods:

A double-blinded, parallel group, randomized controlled clinical trial was conducted among healthy adults. Fifty-two individuals were randomly allocated to four groups (n = 13): Group I – green tea dentifrice, Group II – fluoridated dentifrice, Group III – CHX dentifrice, and Group IV – probiotic dentifrice. Plaque and saliva samples were evaluated for Streptococcus mutans and Lactobacillus at baseline and 15^th and 30^th days of follow-up. Paired t-test and one-way ANOVA were used to compare the mean differences of plaque and salivary S. mutans counts at two and three time periods. Wilcoxon signed-rank and Kruskal–Wallis tests were used to compare the mean Lactobacillus count in plaque and saliva samples at two and three time periods, respectively.

Results:

The mean S. mutans and Lactobacillus counts in plaque and saliva samples were significantly reduced by all the treatment groups at the 30^th day of follow-up. However, Group III showed the highest reduction and was found to be statistically significant (P < 0.05).

Conclusion:

All the four groups exhibited antimicrobial activity by bringing about a significant reduction in the mean S. mutans and Lactobacillus colony counts at the 30^th day of follow-up. Among all the preventive modalities, Group III (CHX dentifrice) showed better results compared to other groups.