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.

Inhibitory Effects of Shikonin Dispersion, an Extract of Lithospermum erythrorhizon Encapsulated in ß-1,3-1,6 Glucan, on Streptococcus mutans and Non-Mutans Streptococci.

Shikonin is extracted from the roots of Lithospermum erythrorhizon, and shikonin extracts have been shown to have inhibitory effects on several bacteria. However, shikonin extracts are difficult to formulate because of their poor water solubility. In the present study, we prepared a shikonin dispersion, which was solubilized by the inclusion of ß-1,3-1,6 glucan, and analysed the inhibitory effects of this dispersion on Streptococcus mutans and non-mutans streptococci. The shikonin dispersion showed pronounced anti-S. mutans activity, and inhibited growth of and biofilm formation by this bacterium. The shikonin dispersion also showed antimicrobial and antiproliferative effects against non-mutans streptococci. In addition, a clinical trial was conducted in which 20 subjects were asked to brush their teeth for 1 week using either shikonin dispersion-containing or non-containing toothpaste, respectively. The shikonin-containing toothpaste decreased the number of S. mutans in the oral cavity, while no such effect was observed after the use of the shikonin-free toothpaste. These results suggest that shikonin dispersion has an inhibitory effect on S. mutans and non-mutans streptococci, and toothpaste containing shikonin dispersion may be effective in preventing dental caries.

Managing oral biofilms to avoid enamel demineralization during fixed orthodontic treatment.

Enamel demineralization represents the most prevalent complication arising from fixed orthodontic treatment. Its main etiology is the development of cariogenic biofilms formed around orthodontic appliances. Ordinarily, oral biofilms exist in a dynamic equilibrium with the host's defense mechanisms. However, the equilibrium can be disrupted by environmental changes, such as the introduction of a fixed orthodontic appliance, resulting in a shift in the biofilm's microbial composition from non-pathogenic to pathogenic. This alteration leads to an increased prevalence of cariogenic bacteria, notably mutans streptococci, within the biofilm. This article examines the relationships between oral biofilms and orthodontic appliances, with a particular focus on strategies for effectively managing oral biofilms to mitigate enamel demineralization around orthodontic appliances.

Effect of Non-Nutritive Sweeteners on Antibacterial Activity of Black and Green Tea Aqueous Extracts against Salivary Mutans Streptococci (in-vitro Study).

Herbal medicines, such as plants and their constituents, have been used globally to treat and cure disorders since antiquity, long before the discovery of modern drugs. Some of these items require an addition to make them more appealing to consumers. This study is an in vitro evaluation of the antibacterial activity of tea (black and green tea aqueous extracts) against salivary Mutans streptococci, followed by an analysis of the effect of non-nutritive sweeteners on the antibacterial activity of these extracts against salivary Mutans streptococci. The examined bacteria were sensitive to various doses of black and green tea aqueous extract, with the inhibition zone expanding as the concentration of the extracts rose. At a dosage of 225mg/ml for black tea extracts and 200mg/ml for green tea extracts, all Mutans isolates were destroyed. In this trial, 1% stevia or sucralose did not inhibit the antibacterial activity of any tea extract, nor did 5% stevia inhibit the antimicrobial activity of black tea extract. In addition, this concentration inhibits the antimicrobial properties of green tea extracts. In this investigation, it found that increasing the content of nonnutritive sweeteners interfered with the antibacterial activity of black and green tea aqueous extract against salivary Mutans streptococci.

The Effect of Nonnutritive Sweeteners on the Antimicrobial Activity of Eucalyptus Extracts against Salivary Mutans Streptococci (in-vitro Study).

The eucalyptus tree is an excellent source of antimicrobial agents; it is used in many oral cure products. The bitter taste of these agents could compromise their usage. Therefore, fortifying the extracts with non-nutritive sweeteners could be a promising procedure for masking their unpleasant taste. This study was an in vitro evaluation of the antimicrobial activity of eucalyptus (alcoholic and aqueous) extracts against salivary Streptococci mutans. It aimed to investigate the effect of non-nutritive sweeteners on the antimicrobial activity of these extracts against salivary S. mutans. The test microbes were sensitive to different concentrations of eucalyptus alcoholic and aqueous extract, and the inhibition zone increased as the concentration of the extracts increased. All the Mutans isolates were killed at a concentration of 75 mg/ml for the alcoholic extract and 175 mg/ml for the aqueous extracts. In this experiment, the concentration of up to 15% stevia and up to 5% sucralose did not affect the antimicrobial activity of eucalyptus alcoholic extract. While the concentration of up to 1% of stevia and sucralose did not interfere with the antimicrobial activity of aqueous eucalyptus extract against salivary S. mutans. An increase in the concentration of non-nutritive sweeteners in this experiment appeared to interfere with the antimicrobial activity of eucalyptus extract against salivary S. mutans.

Role of mutans streptococci, acid tolerant bacteria and oral Candida species in predicting the onset of early childhood caries.

Aim: Early childhood caries is the most common chronic infectious disease in children in the United States. This study, which is part of a larger, longitudinal study exploring oral microbiological components of caries development in children, reports on the impact of total mutans streptococci (MS), total acid tolerant bacteria and Candida species on the development of dental caries in a subset of these children. Of particular interest was the relationship between caries development and co-colonization of mutans streptococci and Candida species. Methods: Children between the ages of 12 and 47 months displaying no evidence of dental caries were recruited for a longitudinal study (n = 130). Twelve age- and gender-matched pairs were selected. In each pair, one child developed caries during the study, and one did not. Whole mouth plaque samples were collected by swab at baseline and every 6 months thereafter for a duration of 18 months and spiral plated for microbial counts (CFU/ml). Cut-offs based on percent of total cultivable flora were designated for all microbial measures. A scoring system designated the Plaque Microbial Index (PMI) was developed for use in statistical analyses to assess potential predictive factors for caries risk assessment. Results: Children who developed caries were significantly more likely to harbor higher percentages of acid tolerant bacteria (p = 0.003), MS (p < 0.001) and have Candida species present (p < 0.001) at ≥1 visit leading up to caries onset. Mean PMI scores derived from the aforementioned microbial measures, were higher for caries active children than caries free children (p = 0.000147). Co-colonization of MS and Candida species was significantly associated with caries development (p < 0.001) and detection of both at the same visit had a 100% positive predictive value and 60% negative predictive value for caries development. Conclusion: In children who developed caries, there was a statistically significant association with the percent of total flora that was acid tolerant, the percent of MS, the presence of Candida and co-colonization of MS and Candida species. Combining these microbial measures into PMI scores further delineated children who developed caries from those who remained caries-free. These microbiological measures show potential as predictive factors and risk assessment tools for caries development.

Identification of a novel bacterium Scardovia wiggsiae in high caries risk adolescence: A metagenomic and melt curve analysis.

Background: Mutans streptococci which comprise only 2% have long been presumed to be the specific pathogen responsible for caries. A novel caries associated bacterium namely Scardovia wiggsiae is recognized to be ecologically competitive in active caries lesions. The actual pathogen needs to be identified, so as to specifically target and reduce the prevalence of caries in a given community. Aim: The aim of the study is to evaluate the presence of S. wiggsiae in combination with other bacteria in caries risk adolescence. Methods: Sixty adolescent subjects were screened. Phase I-to determine the prevalence of S. wiggsiae in saliva, plaque and dentinal caries samples of low and high caries risk individuals (n = 30 each) using polymerase chain reaction (PCR); Phase-II-to identify its presence by 16SrRNA metagenomic analysis and quantitatively evaluate the cariogenic pathogen using high-resolution melt curve analysis and real-time PCR. Results: Highest prevalence of S. wiggsiae was observed in dentinal caries followed by plaque and saliva samples of high caries risk individuals under PCR analysis. Metagenomic analysis showed two-fold statistically increased presence of Lactobacilli and Bifidobacteriaceae (S. wiggsiae) in dentinal samples compared to plaque samples (P = 0.05). Mutans streptococcus recorded the minimum. Conclusion: Scardovia wiggsiae is identified as one of the predominant microorganism.

Efficacy of Probiotic, Chlorhexidine, and Sodium Fluoride Mouthrinses on Mutans Streptococci in 8- to 12-Year-Old Children: A Crossover Randomized Trial.

INTRODUCTION: The oral cavity is home to a diverse and distinct microbiome. While the role of oral bacteria in cariogenic and other dental diseases is irrefutable, their beneficial effects in the form of probiotics (PB) has been less studied, especially pertaining to oral diseases in children. This study compares the efficacy of a PB mouthrinse with 0.12% chlorhexidine (CHX) and 0.05% sodium fluoride (NaF) mouthrinse on the colony counts of mutans streptococci (MS) in children. METHODS: A triple-blind crossover randomized trial between interventional groups was planned. Fifty-one children between 8 to 12 years of age were divided into three groups (I, II, and III) and were exposed to all three mouthrinses (A, B, and C) by randomized allocation for a period of two weeks with an inter-phase washout period of four weeks. Pre- and post-interventional MS counts (CFU/mL) were assessed, and the mean change was analysed using the t test (intragroup) and ANOVA (intergroup and crossover). RESULTS: The mean changes in the colony counts obtained with the use of PB, CHX, and NaF mouthrinses were -1.0223 (-1.2201 to -0.8246), -0.9564 (-1.1503 to -0.7626), and -0.9511 (-1.1554 to -0.7467), respectively, which were statistically significant (p < 0.0001). However, the intergroup comparison for the mean change in colony counts revealed no statistically significant differences (p > 0.05). CONCLUSION: The study concluded that the PB mouthrinse was equally efficacious as compared to CHX and NaF mouthrinses against MS in 8- to 12-year-old children. However, further studies are recommended to strengthen the evidence.

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.

The Association of Early Childhood Caries with Salivary Antimicrobial Peptide LL37 and Mutans Streptococci.

PURPOSE: This study aims to determine the relation of salivary LL37 level and mutans streptococci levels in early childhood caries (ECC). STUDY DESIGN: A case-control study was performed in children ≤71 months old. Unstimulated whole saliva was collected and the level of salivary LL37 was measured using an enzyme-linked immunosorbent assay kit. The mutans streptococci oral bacteria were isolated from saliva and identified using a modified SB-20 culture medium (SB-20M). Data were analyzed using descriptive statistics, bivariate, and Spearman's rank correlation analysis. RESULTS: The was a variability of salivary LL37 level among the children and the level was significantly associated with age and races. The median (IQR) value of salivary LL37 in caries-free (CF) children was significantly higher 393.50 (580.55) ng/mL compared to 172.50 (234.65) ng/mL in the ECC group. The ECC children exhibited a significantly higher count of S. mutans and S. sobrinus compared to the CF children. An inverse weak correlation between salivary LL37 and dmft was also observed. CONCLUSIONS: The low salivary LL37 level and higher S. mutans and S. sobrinus count in ECC supported the protective role of salivary LL37 against dental caries. Further studies are required to explore the definite relation between salivary LL37 levels and dental caries.

Green Tea-Derived Epigallocatechin Gallate Inhibits Acid Production and Promotes the Aggregation of Streptococcus mutans and Non-Mutans Streptococci.

It has been suggested that green tea-derived epigallocatechin gallate (EGCG), which has antimicrobial properties, might help prevent dental caries. However, the detailed properties of EGCG remain unclear. In this study, the antimicrobial properties of EGCG were evaluated by examining its bactericidal activity, its inhibitory effects against bacterial growth, acid production, acidic end-product formation, and sugar uptake (phosphoenolpyruvate-dependent phosphotransferase system, PEP-PTS activity), and its effects on bacterial aggregation, using monocultured planktonic cells of Streptococcus mutans and non-mutans streptococci. Coincubating S. mutans with EGCG (1 mg/mL) for 4 h had no bactericidal effects, while it decreased the growth and acid production of S. mutans by inhibiting the activity of the PEP-PTS. EGCG (2 mg/mL) caused rapid bacterial cell aggregation and had reduced the optical density of S. mutans cell suspension by 86.7% at pH 7.0 and 90.7% at pH 5.5 after 2 h. EGCG also reduced the acid production of non-mutans streptococci, including S. sanguinis, S. gordonii, and S. salivarius, and promoted the aggregation of these non-mutans streptococci. Furthermore, these antimicrobial effects of short-term EGCG treatment persisted in the presence of saliva. These results suggest that EGCG might have short-term antibacterial effects on caries-associated streptococci in the oral cavity.

Urethane Dimethacrylate Influences the Cariogenic Properties of Streptococcus Mutans.

Concerns regarding unbound monomers in dental composites have increased with the increased usage of these materials. This study assessed the biological effects of urethane dimethacrylate (UDMA), a common monomer component of dental composite resins, on the cariogenic properties of Streptococcus mutans. Changes in the growth rate, biofilm formation, interaction with saliva, surface hydrophobicity, adhesion, glucan synthesis, sugar transport, glycolytic profiles, and oxidative- and acid-stress tolerances of S. mutans were evaluated after growing the cells in the presence and absence of UDMA. The results indicated that UDMA promotes the adhesion of S. mutans to the underlying surfaces and extracellular polysaccharide synthesis, leading to enhanced biofilm formation. Furthermore, UDMA reduced the acid tolerance of S. mutans, but enhanced its tolerance to oxidative stress, thus favoring the early stage of biofilm development. UDMA did not significantly affect the viability or planktonic growth of cells, but diminished the ability of S. mutans to metabolize carbohydrates and thus maintain the level of intracellular polysaccharides, although the tendency for sugar transport increased. Notably, UDMA did not significantly alter the interactions of bacterial cells with saliva. This study suggests that UDMA may potentially contribute to the development of secondary caries around UDMA-containing dental materials by prompting biofilm formation, enhancing oxidative tolerance, and modulating carbon flow.

Remineralization potential and caries preventive efficacy of CPP-ACP/Xylitol/Ozone/Bioactive glass and topical fluoride combined therapy versus fluoride mono-therapy - a systematic review and meta-analysis.

OBJECTIVE: To compare the remineralization potential and caries preventive efficacy of CPP-ACP/bioactive glass/xylitol/ozone and topical fluoride (TF) combined therapy versus TF mono-therapy. MATERIAL AND METHODS: Embase, PubMed, Scopus, Web of Science and Cochrane databases were searched. 4457 records were screened and 26 trials were included. Data from 16 trials was pooled using Review Manager 5.4. Level of significance was p < .05. The certainty of the evidence was evaluated using GRADE. RESULTS: Pooled analysis of two trials for white spot lesions (WSLs) regression (SMD -0.6, 95% CI: [-1.07 to -0.14], p = .01) and three trials for post-intervention DIAGNOdent values (SMD -1.24, 95% CI: [-1.96 to -0.52], p = .0007) significantly favoured CPP-ACP-TF combined therapy over TF mono-therapy. The sub-group analysis for caries increment (SMD -0.14, 95% CI: [-0.21 to -0.07], p < .0001) and the post intervention S mutans count (SMD -0.42, 95% CI: [-0.62 to -0.23], p < .0001) significantly favours 'xylitol-TF' and 'CPP-ACP-TF' combined therapy respectively. The high/unclear risk of bias, imprecision and indirectness of the included trials presented a low certainty of evidence. CONCLUSION: CPP-ACP-TF exhibits superiority over TF monotherapy in remineralizing existing lesions and demonstrates better antibacterial effect, whereas it is not more effective for preventing caries incidence. However, Xylitol exerts an added benefit over fluoride alone in preventing caries increment. The low-certainty evidence highlights the need for more good quality trials.

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.

Establishment of microcosm biofilm models that reproduce a cariogenic diet intake.

Biofilms were developed from human saliva on bovine enamel discs in four experimental conditions to investigate dental caries development: feast and famine (M1), abundance and scarcity (M2), three meals daily (M3), and three meals plus two snacks daily (M4). The main difference between these models was the diet for microbial growth. The evaluations included verifying the pH of the spent culture media and analyzing the enamel discs for demineralization (microhardness and roughness) and biofilms (biomass, viable populations of mutans streptococci, and total microbiota). Two major behaviors were observed: M1 and M2 promoted an acidic environment, while M3 and M4 maintained pH values closer to neutral. The demineralization process was slower in the neutral groups but more pronounced in M3, while a greater increase in microbiota and biomass was observed over time for both neutral groups. Thus, the M3 model was better at mimicking the oral environment that leads to demineralization.

Effects of Caries Activity on Compositions of Mutans Streptococci in Saliva-Induced Biofilm Formed on Bracket Materials.

This study aimed to investigate effects of caries activity on composition of mutans streptococci in saliva-induced biofilms formed on bracket materials. Three bracket materials were used as specimens: ceramic, metal, and plastic. After saliva was collected using a spitting method from caries-active (CA, decayed, missing, filled teeth (DMFT) score ≥ 10) and caries-free (CF, DMFT score = 0) subjects, saliva was mixed with growth media in a proportion of 1:10. The saliva solution was then incubated with each bracket material. After a saliva-induced biofilm was developed on the surface of the bracket material, the amounts of total bacteria and mutans streptococci were determined using real-time polymerase chain reaction. The results showed that biofilms from CA saliva contained more mutans streptococci but less total bacteria than biofilms from CF saliva, regardless of material type. Adhesion of total bacteria to ceramic was higher than to plastic, regardless of caries activity. Mutans streptococci adhered more to ceramic than to metal and plastic in both biofilms from CA and CF saliva, but there was a difference in adhesion between Streptococcus mutans and Streptococcus sobrinus. The amount of S. mutans was higher than that of S. sobrinus in biofilms from CA saliva despite similar amounts of the two strains in biofilms from CF saliva. The stronger adhesion of S. mutans to ceramic than to metal and plastic was more evident in biofilms from CA saliva than in biofilms from CF saliva. This study suggests that caries activity and material type significantly influenced composition of mutans streptococci in biofilms formed on bracket materials.

Effect of divalent ions on cariogenic biofilm formation.

BACKGROUND: Divalent cations are able to interact with exopolysaccharides (EPS) and thus are capable to modify the structure and composition of dental biofilm. At the moment, little is known about the adsorption of metals by cariogenic EPS; thus, the aim of the present study was to evaluate the effect of divalent ions (calcium, magnesium, and zinc) on the growth and biofilm formation of mutans streptococci and on the dissolution of hydroxyapatite as well as to investigate their binding to the bacterial EPS. RESULTS: S. mutans strains used in this study show the highest tolerance towards calcium of the ions tested. Growth parameters showed no differences to control condition for both strains up to 100 mM; revealing natural tolerance to higher concentration of calcium in the surroundings. Although excessive levels of calcium did not impair the growth parameters, it also did not have a positive effect on biofilm formation or its binding affinity to EPS. Magnesium-saturated environment proved to be counterproductive as strains were able to dissolve more Ca2+ from the tooth surface in the presence of magnesium, therefore releasing excessive amounts of Ca2+ in the environment and leading to the progression of the disease. Thus, this supports the idea of self-regulation, when more Ca2+ is released, more calcium is bound to the biofilm strengthening its structure and however, also less is left for remineralization. Zinc inhibited bacterial adhesion already at low concentrations and had a strong antibacterial effect on the strains as well as on calcium dissolution; leading to less biofilm and less EPS. Additionally, Zn2+ had almost always the lowest affinity to all EPS; thus, the unbound zinc could also still remain in the surrounding environment and keep its antimicrobial properties. CONCLUSION: It is important to maintain a stable relationship between calcium, magnesium and zinc as excessive concentrations of one can easily destroy the balance between the three in cariogenic environment and lead to progression of the disease.

Long-Term Fluctuation of Oral Biofilm Microbiota following Different Dietary Phases.

Caries development is associated with shifts in the oral biofilm microbiota and primarily linked to frequent simple carbohydrate consumption. Different nutritional ingredients can either promote or prevent caries development. To investigate the effects of selected ingredients on the oral biofilm microbiota in situ, 11 study participants underwent 3-month-long dietary phases with intake of a regular diet (PI), additional frequent sucrose (PII), milk and yoghurt (PIII), and a diet rich in dietary fiber (PIV) and then returned to their regular diet (PV). Oral biofilm was sampled and analyzed applying 16S rRNA Illumina MiSeq sequencing. Additionally, the effect on the enamel was analyzed by measuring enamel surface roughness with laser scanning microscopy. The beta-diversity results showed that the microbiota in all the following phases differed significantly from PI and that the microbial community in PII was significantly different from all other phases. The abundance of the genus Streptococcus fluctuated over the course of the five phases, with a significant increase in PII (P = 0.01), decreasing in PIII and PIV (PIII and PIV versus PII: P < 0.00001) and increasing again toward PV. Other taxa showed various fluctuations of their abundances, with PV returning approximately to the levels of PI. In conclusion, while elevated sucrose consumption favored caries-promoting non-mutans streptococci, frequent milk and yoghurt intake caused a significant decrease in the abundance of these microbial taxa and in addition reduced enamel surface roughness. These results indicate that modulations of the oral biofilm microbiota can be attained even in adults through dietary changes and corresponding recommendations can be made for the prevention of caries development.IMPORTANCE Caries affects a large proportion of the population worldwide, resulting in high treatment costs. Its etiology can be ascribed to shifts of the microbiota in dental biofilms primarily driven by dietary factors. It is unclear how diet affects the microbial community of plaque biofilm in situ and whether it can be modulated to help prevent caries development. To address these issues, we analyzed changes of the in situ plaque microbiota following 3-month-long dietary changes involving elevated sucrose, dairy, and dietary fiber consumption over a period of 15 months. Applying high-throughput sequencing, we found non-mutans streptococci, a taxonomic group involved in the beginning stages toward microbial dysbiosis, in decreased abundance with elevated dairy and dietary fiber intake. Through analysis of the enamel surface roughness, these effects were confirmed. Therefore, correspondent dietary measures can be recommended for children as well as adults for caries prevention.

Effects of xylitol and erythritol consumption on mutans streptococci and the oral microbiota: a systematic review.

OBJECTIVE: A systematic review of published data was conducted with the aim of assessing effects of xylitol and erythritol consumption on levels of mutans streptococci (MS) and the oral microbiota. MATERIALS AND METHODS: Electronic and hand searches were performed to find clinical microbiological studies concerning the consumption of xylitol and erythritol chewing gum or candies, and published between 2000 and 2019. Prospective randomized controlled clinical trials conducted in healthy subjects were included in the review. RESULTS: The initial search identified 561 xylitol and 83 erythritol studies. After applying inclusion and exclusion criteria, 21 xylitol studies and one erythritol study were reviewed. The review identified nine xylitol studies with a fair or high quality, four conducted in children and five in adults, all demonstrating a decrease in MS levels in association with habitual consumption of xylitol. The three microbiota studies employing multispecies probe approaches revealed no effects for xylitol on the microbiota. The only erythritol study fulfilling the inclusion criteria showed no consistent effects on MS levels. CONCLUSIONS: Xylitol consumption is likely to decrease MS counts but it may not change the overall microbiota. Xylitol shows thus properties of an oral prebiotic. More studies are needed to demonstrate the effects of erythritol on MS.

The FT-IR and Raman Spectroscopies as Tools for Biofilm Characterization Created by Cariogenic Streptococci.

Fourier transform infrared (FT-IR) and Raman spectroscopy and mapping were applied to the analysis of biofilms produced by bacteria of the genus Streptococcus. Bacterial biofilm, also called dental plaque, is the main cause of periodontal disease and tooth decay. It consists of a complex microbial community embedded in an extracellular matrix composed of highly hydrated extracellular polymeric substances and is a combination of salivary and bacterial proteins, lipids, polysaccharides, nucleic acids, and inorganic ions. This study confirms the value of Raman and FT-IR spectroscopies in biology, medicine, and pharmacy as effective tools for bacterial product characterization.