Streptococcus Mutans Biofilm Research Articles

Small cyclic dipeptide produced by Lactobacillus rhamnosus with anti-biofilm properties against Streptococcus mutans biofilm

The human oral cavity harbors many bacterial species collectively termed the oral microbiome and is integral for maintaining oral health. Dysbiosis of oral microbiota leads to common oral diseases, including dental caries, gingivitis, and periodontitis. Streptococcus mutans is the primary causative agent of dental caries. Studies have explored the use of probiotic Lactobacillus spp. to mitigate S. mutans biofilms. In the present study, we have tested the use of Lactobacillus rhamnosus extracts/metabolites for anti-biofilm properties. A small organic compound/metabolite was isolated from the cell-free supernatant of L. rhamnosus, and this metabolite resulted in a dose-dependent inhibition of S. mutans biofilms. Confocal microscopy revealed that the thickness of S. mutans biofilms was severely reduced upon metabolite treatment. With the help of FTIR spectra and mass spectrometry analysis, the molecular formula (C11H19O2N2) was deduced. The inhibitor compound was further identified as a small cyclic peptide, cyclo (-L-Leu-L-Pro). Our data also revealed that isolated metabolite impedes S. mutans biofilms by modulating gene expression of several essential genes involved in biofilm establishment.

The anti-caries effects of copper tetraamine fluoride on enamel: An in vitro study

ObjectiveTo investigate the antibacterial, remineralising, and discolouring effects of copper tetraamine fluoride (CTF) on artificial enamel caries. MethodHuman enamel blocks with artificial caries were treated with CTF, silver diamine fluoride (SDF, positive control) and water (negative control) before being challenged with Streptococcus mutans. The morphology, viability, and growth kinetics of biofilm were evaluated using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony-forming unit (CFU) counting. The lesion depths, mineral loss, micro-hardness, and crystal characteristics were assessed using micro-computed tomography, Knoop Hardness Tester, and X-ray diffraction (XRD), respectively. The discolouring property was assessed by spectrophotometry. ResultsSEM showed that bacteria completely covered the enamel surface treated with water, but not the enamel surface treated with CTF and SDF. CLSM showed dead-to-live ratio of biofilm treated with CTF, SDF and water were 0.8 ± 0.1, 0.9 ± 0.2 and 0.5 ± 0.1 (p < 0.001, CTF, SDF>Water). Log10 CFU values of biofilm treated with CTF, SDF and water were 7.7 ± 0.2, 7.7 ± 0.1 and 8.1 ± 0.1 (p < 0.001, CTF, SDF<Water). Lesion-depths (μm) of the CTF, SDF and water groups were 93 ± 6, 92 ± 7 and 152 ± 29 (p < 0.001, CTF, SDF<Water). Mineral loss (gHApcm−3) of the CTF, SDF and water groups were 0.4 ± 0.1, 0.4 ± 0.2 and 1.0 ± 0.2 (p < 0.001, CTF, SDF<Water). Knoop hardness of the CTF, SDF and water groups were 70 ± 23, 68 ± 16 and 21 ± 10 (p < 0.05, CTF, SDF>Water). XRD revealed well-crystallised hydroxyapatite in enamel treated with CTF and SDF, but not water. Spectrophotometry showed ΔE values of the CTF, SDF and water groups were 5 ± 3, 54 ± 6 and 6 ± 2 (p < 0.001, CTF, water<SDF). ConclusionCTF inhibited Streptococcus mutans biofilm and remineralised artificial enamel caries without discolouration. Clinical significanceIf CTF is successfully translated into clinical use, it can be a simple agent for clinicians to arrest enamel caries.

Effect of glycerol monolaurate nanocapsules on Streptococcus mutans biofilm in vitro

This study aimed to prepare and apply nanocapsules containing glycerol monolaurate for eradicating Streptococcus mutans biofilms. The interfacial deposition method of the preformed polymer synthesized the nanocapsules characterized for mean diameter, polydispersity index, zeta potential, pH, and morphology by transmission electron microscopy. The microdilution method investigated antimicrobial activity. Crystal violet staining determined biomass quantification and the ability to inhibit biofilm formation. The study also measured exopolysaccharide production and the number of viable colonies. The characterization outcomes indicated acceptable values for the mean diameter 198.1 ± 2, a polydispersity index of 0.087 ± 0.018, a zeta potential of -21.30 ± 2.00 mV, a pH of 6.19 ± 0.12, and typical nanostructure morphology. The evaluations of minimum inhibitory and bactericidal concentrations of glycerol monolaurate (free and nanoencapsulated) revealed their ineffectiveness in inhibiting microorganisms. Only free glycerol monolaurate inhibits S. mutans growth with 125 µg/mL. Biomass, exopolysaccharide content, and viable colonies in the biofilm were analyzed to assess the compounds' ability to inhibit biofilm formation. The tested compounds did not significantly reduce the formed biofilm. Despite unfavorable outcomes of the formulated preparation, further experimentation with a new formulation is encouraged to explore alternative strategies and potential improvements.

Novel Antibacterial Resin Coating for Dental Provisional Crowns to Suppress Biofilms and Inhibit Secondary Caries

Provisional crowns are often used in dentistry for prolonged periods, but bacterial attachment and dental plaque often lead to gingival inflammation and secondary caries. The aims of this research were to develop a novel resin-based antibacterial provisional crown coating to prevent secondary caries and investigate the physical properties and antibacterial efficacy. The resin-based coating was prepared by addition of triethylene glycoldivinylbenzyl ether and urethane dimethacrylate, with the antibacterial monomer dimethylaminododecyl methacrylate (DMADDM) incorporated at different mass fractions. Surface characteristics including surface roughness and contact angle were assessed. The antibacterial effects were evaluated by 48 h biofilms of Streptococcus mutans (S. mutans) on provisional crowns coated with the resin-based coating. No statistically significant difference was observed in surface roughness across all groups (p &gt; 0.05), showing that adding DMADDM did not have a negative impact on surface roughness. The contact angle results revealed a significant difference in hydrophilicity between different concentrations of DMADDM (p &lt; 0.01), but overall hydrophilicity did not negatively affect the performance of the coating. The incorporation of 5% DMADDM demonstrated a significant antibiofilm effect on S. mutans biofilm CFU with a 4-log reduction compared to controls (p &lt; 0.01). Significant reductions of 4–5 folds were observed in biofilm metabolic activity and lactic acid production (p &lt; 0.01). The findings suggest that the novel coating material could enhance the long-term performance and clinical outcomes of provisional crowns, contributing to better patient oral health.

Cryptocarya moschata fractions decrease planktonic cells and biofilms of Candida albicans and Streptococcus mutans.

Extracts of Cryptocarya species have been shown to reduce biofilms, demonstrating their antimicrobial effects. The extracts can be fractionated to optimize their potential. In this study, we evaluated the antimicrobial activity of Cryptocarya moschata fractions against planktonic cells and biofilms of Candida albicans and Streptococcus mutans. Four fractions were prepared: 100% hexane, acetate/hexane 1:1, 100% ethyl acetate, and water. The effect of the fractions on planktonic cells was assessed by counting the colony-forming units per milliliter (CFU/mL). Biofilm tests included CFU/mL, cell metabolic activity, and qualitative analysis using confocal laser scanning microscopy (CLSM). Results were analyzed by the Mann-Whitney U test (α = 0.05). The fractions contained lipophilic constituents, styrylpyrones, glycosylated flavonoids, and alkaloids. Acetate/hexane (1:1) and 100% ethyl acetate fractions reduced the CFU/mL of planktonic C. albicans. C. moschata fractions did not affect planktonic S. mutans. For biofilms, the fractions reduced the CFU/mL (from 2-5 logs) and cell metabolic activity (approximately 80% reduction in a single-species biofilm). CLSM showed the fractions reduced microorganism viability and damaged the extracellular matrix of biofilms. We conclude that the acetate/hexane 1:1 and 100% ethyl acetate C. moschata fractions exhibit antimicrobial effects against biofilms.

A comparative evaluation of the antimicrobial efficacy of Chlorhexidine and Chlorine dioxide on self-ligating brackets contaminated with Streptococcus mutans biofilm- An In vitro study

ObjectiveTo evaluate and compare antimicrobial efficacy of Chlorhexidine and Chlorine dioxide mouthwashes on S.mutans biofilm created on metal and ceramic self-ligating brackets. Materials and methodsA total of 162 metal and ceramic self-ligating brackets (3M™ SmartClip™ & Clarity SL™) were randomly divided into 3 groups and 2 subgroups. Standard procedures were followed to coat all brackets with S.mutans biofilm. The biofilms were cultivated which were then subjected to the effects of the mouthwashes. Quantitative assessment was carried out by comparing the number of viable colonies of S.mutans. A Mann-Whitney U test was used to compare the data between the experimental and control groups. (p < 0.05). ResultWhen compared to untreated controls the antimicrobial efficacy of Chlorhexidine Digluconate and Chlorine Dioxide mouthwashes was found to be statistically significant (p = 0.00). The comparison between Chlorhexidine digluconate and Chlorine dioxide mouthwashes was not statistically significant in Ceramic self-ligating group (p = 0.502) and statistically significant in Metal self-ligating group (p = 0.001) ConclusionS mutans colonies on metal and ceramic self-ligating brackets can be reduced effectively by Chlorhexidine digluconate and Chlorine dioxide mouthwashes. Chlorhexidine digluconate more effective for metal bracket group. Both mouthwashes had comparable antimicrobial effectiveness, with the difference in the number of viable colonies following exposure for ceramic bracket groups.

Effects of Tooth Desensitizers on Streptococcus mutans Biofilm Formation Using a Modified Robbins Device Flow Cell System.

This study aimed to assess the antibiofilm effects of dentin desensitizers using a modified Robbins device flow cell system. The test desensitizers were Saforide, Caredyne Shield, and Clinpro White Varnish. Standardized dentin specimens were prepared from human single-rooted premolars, treated with one of the materials, and mounted on the modified Robbins device flow cell system. Streptococcus mutans biofilms were developed for 24 h at 37 °C under anaerobic conditions. Scanning electron microscopy, fluorescence confocal laser scanning microscopy, viable and total cell counts, acid production, and gene expression analyses were performed. A wavelength-dispersive X-ray spectroscopy electron probe microanalyzer was used to analyze the ion incorporations. Clinpro White Varnish showed the greatest inhibition, suggesting its suppression of bacterial adherence and transcription of genes related to biofilm formation. Saforide reduced only the number of viable bacteria, but other results showed no significant difference. The antibiofilm effects of Caredyne Shield were limited. The uptake of ions released from a material into dentin varies depending on the element. Clinpro White Varnish is effective for the short-term treatment of tooth sensitivity due to dentin demineralization. It prioritizes remineralization by supplying calcium and fluoride ions while resisting biofilm formation.

Efficacy of silver diamine fluoride (SDF) in arresting dentin caries against inter-kingdom biofilms of Streptococcus mutans and Candida albicans.

To compare, in vitro, the efficacy of three proprietary silver diamine fluoride (SDF) products in mitigating progression of dentinal caries induced by an inter-kingdom, dual-species, bacterial-yeast biofilm. Human dentin blocks were demineralized to create artificial caries lesions and randomized into three SDF test groups: Saforide, Topamine, T-SDF, and an aqueous control (n = 26 per group). After application of foregoing SDF variants, the blocks were incubated with Streptococcus mutans and Candida albicans for 24 h for biofilm development, and subsequently subjected to a microbe-induced, pH-cycling process for 7 days, to mimic the oral eco-system. The biofilm cell viability and surface topography were assessed by colony-forming units (CFUs) and scanning electron microscopy respectively. The lesion depth and mineral density were evaluated by micro-computer tomography. SDF precipitate and matrix-to-mineral ratio were evaluated by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. Standard, accepted methodology was used for all these evaluations and procedures. After pH cycling, the SDF groups demonstrated comparable inhibition of the biofilm relative to the control. the log CFU of S. mutans for Saforide, Topamine, T-SDF, and control were 6.69±0.73, 6.48±0.56, 6.63±0.66, and 8.01±0.45, respectively. For C. albicans, the log CFU were 4.86±0.44, 4.72±0.53, 4.92±0.29, and 5.60±0.27, respectively. The log CFU of S. mutans and C. albicans in the SDF groups were significantly lower than the control group (p<0.001). Further, the lesion depth decreased by approximately 14.79±7.00% in the SDF groups, while it increased by 11.07±8.61% in the control (p<0.001), and the mineral density increased by 16.36±4.58% in the SDF group, as opposed to a 5.59±2.64% reduction in the control (p<0.001) implying their caries mitigating effect. These findings were corroborated by SEM images of the lesions. SDF significantly mitigated dentin caries due to an assault by a polymicrobial plaque biofilm whilst arresting mineral loss and lesion growth. There was no difference in the caries-arresting efficacy of the compared SDF variants.

Enhancing Removable Partial Dentures Hygiene: Investigating Mucolytic Agents and Biocides for Disrupting Biofilms and Improving Antimicrobial Efficacy.

This study evaluates the antibiofilm action of 2.5 mg/mL peracetic acid (PA), 0.5 mg/mL cetylpyridinium chloride (CPC), and 160 mg/mL N-Acetylcysteine (NAC) against multispecies biofilm of Streptococcus mutans, Staphylococcus aureus, Candida albicans, and Candida glabrata, developed on surfaces of heat-polymerizing acrylic resin (AR) and cobaltchromium (Co-Cr) alloy. A multispecies biofilm was grown on the surface of AR and Co-Cr specimens (Ø 12×3mm). After biofilm maturation, the specimens were immersed in experimental solutions and evaluated through biofilm viability (CFU) (n&#61;9), biofilm metabolic activity (XTT) (n&#61;9), biofilm-covered areas (Live/Dead) (n&#61;2), effects on the extracellular polymeric substance (EPS) (n&#61;2) and biofilm morphology (n&#61;1). Data were analyzed by ANOVA and the Tukey post-test or Kruskal-Wallis followed by the Dunn post-test (α&#61;.05). Overall, all evaluated solutions impacted biofilm viability. PA presented wider activity by reducing CFU of all microorganisms on both surfaces, XTT (P<.001) and Live/Dead (P<.001). NAC had a notorious effect in reducing the viability of bacteria without affecting the yeasts. NAC reduced XTT on AR (P&#61;.006) and Co-Cr (P&#61;.003) but did not reduce the aggregated biofilm layer. CPC had distinct effect according to the surface, being most effective in reducing CFU on AR than the Co-Cr surface. However, it did not influence XTT, and the amount of residual aggregated biofilm. PA provided the greatest antibiofilm action, while CPC and NAC showed intermediate action. Nonetheless, no solution was able to completely remove the biofilm adhered to the surfaces of heat-polymerizing AR and Co-Cr alloy.

Comparing The Antibacterial Effectiveness Of Indigenously Derived Propolis In Various Vehicles Against Streptococcus Mutans Biofilm Formation: A Study With Contemporary Pulp Capping Agents

Comparing The Antibacterial Effectiveness Of Indigenously Derived Propolis In Various Vehicles Against Streptococcus Mutans Biofilm Formation: A Study With Contemporary Pulp Capping Agents

Comparative Evaluation of Biofilm Formation on Temporization Crown Materials Used in the Rehabilitation of Primary Dentition With Different Polishing Materials: An In Vitro Study.

Introduction Advancements in dental materials have enhanced aesthetic treatments for managing dental caries and injuries in primary dentition. Bis-acryl composite-based temporization materials are now preferred for restoring primary crowns due to their superior properties. However, prolonged exposure to dietary and hygienic factors can lead to discoloration and roughness, making efficient polishing essential to prevent plaque buildup. Objective This study aims to evaluate Streptococcus mutans biofilm formation on temporization material polished with different polishing systems. Methods This study tested bis-acryl methacrylate temporization material. Thirty disk-shaped specimens were prepared and divided into three groups according to the polishing system used (n = 10 per group): Shofu Super Snap mini kit (Shofu, San Marcos, CA), aluminum oxide polishing paste, and propol polishing paste. Each group's specimens were polished according to the manufacturer's instructions. Surface roughness (SR), scanning electron microscopy (SEM) morphological analysis, and Streptococcus mutans biofilm formation were assessed for each group. Results The results showed significant differences in roughness average (Ra) values among the polishing materials, with the Shofu Super Snap mini kit having the highest roughness (Ra = 2.04), followed by propol polishing paste (Ra = 1.30)and aluminum oxide paste (Ra = 0.75). Additionally, polishing methods significantly affected mean colony-forming unit (CFU) levels, with the first group having the highest mean CFU value (0.24), with SEM images showing substantial biofilm formation by Streptococcus mutans. Conclusion Bacterial biofilm formation on the aluminum oxide paste group's surface differed from that on the propol polishing paste and aluminum oxide disc groups. The polishing techniques that we tested significantly influenced surface properties and biofilm formation. These findings suggest that selecting an appropriate polishing system can reduce the risk of gingival inflammation associated with temporization materials.

Psidium guajav-mediated zinc oxide nanoparticles as a multifunctional, microbicidal, antioxidant and antiproliferative agent against destructive pathogens.

Bio-inspired zinc oxide nanoparticles are gaining immense interest due to their safety, low cost, biocompatibility, and broad biological properties. In recent years, much research has been focused on plant-based nanoparticles, mainly for their eco-friendly, facile, and non-toxic character. Hence, the current study emphasized a bottom-up synthesis of zinc oxide nanoparticles (ZnO NPs) from Psidium guajava aqueous leaf extract and evaluation of its biological properties. The structural characteristic features of biosynthesized ZnO NPs were confirmed using various analytical methods, such as UV-Vis spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). The synthesized ZnO NPs exhibited ahydrodynamic shape with an average particle size of 11.6-80.2nm. A significant antimicrobial efficiency with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 40 and 27µg/ml for Enterococcus faecalis, followed by 30 and 40µg/ml for Staphylococcus aureus, 20 and 30µg/ml for Staphylococcus mutans, 30µg/ml for Candida albicans was observed by ZnO NPs. Additionally, they showed significant breakdown of biofilms of Streptococcus mutans and Candida albicans indicating their future value in drug-resistance research. Furthermore, an excellent dose-dependent activity of antioxidant property was noticed with an IC50 of 9.89µg/ml. The antiproliferative potential of the ZnO NPs was indicated by the viability of MDA MB 231 cells, which showed adrastic decrease in response to increased concentrations of biosynthesized ZnO NPs. Thus, the present results open up vistas to explore their pharmaceutical potential for the development of targeted anticancer drugs in the future.

Effects of a Novel Magnetic Nanomaterial on Oral Biofilms

Dental caries is one of the most common oral chronic infectious diseases, and novel antibacterial materials must be developed to control plaque and inhibit formation of dental caries. Combining magnetic nanomaterials with antibacterial agents to decrease the formation of bacterial biofilm has been a hot topic in the biomedical field. The present study developed a novel magnetic nanomaterial chemically combined with dimethylaminododecyl methacrylate (DMADDM) and initially investigated its inhibiting effects on biofilms by using traditional caries-related bacteria and saliva flora models. The novel magnetic nanomaterials successfully loaded DMADDM according to thermogravimetric analysis, Fourier transform infrared spectroscopy, x-ray diffraction, vibrating sample magnetometry, scanning electron microscopy, and transmission electron microscopy results. Further, the novel nanoparticle Fe3O4@SiO2@DMADDM with concentration of 8 mg/mL could effectively reduce Streptococcus mutans biofilm and decrease the production of lactic acid. The 16S rDNA sequencing revealed that Fe3O4@SiO2@DMADDM could depress the proportion of caries-related bacteria in saliva-derived biofilm, such as Streptococcus, Veillonella, and Neisseria. Therefore, Fe3O4@SiO2@DMADDM is a novel effective antibacterial magnetic nanomaterial and has clinical potential in plaque control and dental caries prevention.

The impact of Streptococcus mutans biofilms on the color stability and topographical features of three lithium disilicate ceramics.

Secondary caries around ceramic restorations is the most common reason for the replacement of fixed dental prostheses (FDPs). Therefore, it is important to examine the susceptibility of different ceramic materials to biofilm formation. This study aimed to evaluate biofilm development and associated roughness and color alterations in three lithium disilicate ceramics: Emax CAD (EC), Emax Press (EP), and LiSi Press (LP). Streptococcus mutans biofilms were grown on the three ceramics (n = 10 per group) for 7 days. Surface roughness values and color alteration were assessed before and after the biofilm using a non-contact profilometer and spectrophotometer, respectively. Biofilm growth was evaluated using colony-forming units (CFUs) and scanning electron microscope (SEM) images. The data were analyzed using one-way ANOVA and Tukey tests. There was a significant (p≤0.001) growth of S. mutans colonies on EC (6.75 ± 0.56) and EP (6.72 ± 0.54) specimens compared to LP, which showed no biofilm growth. The change in average surface roughness (∆Ra, nm) was significantly lower (p < 0.001) in the EC specimens (0.029 ± 0.003) compared to the EP (0.055 ± 0.012) and LP (0.041 ± 0.010). When the changes in the Rv and Rt values were investigated, no significant difference was observed among the groups. Following the biofilm challenge, the change in color (∆E00) was significantly lower (p = 0.005) in the LP group (1.68 ± 1.45) compared to the EC group (3.89 ± 1.50) and no significant difference was observed between the EP group (2.74±1.01) and the other two ceramics (p ≥ 0.05). LP ceramics exhibited superior resistance to S. mutans biofilm formation and associated changes in surface roughness and color compared to the Emax CAD and Emax Press ceramics. These findings suggest that the LiSi Press material may be more favorable to mitigate the risk of secondary caries.

Cocktail Approach with Polyserotonin Nanoparticles and Peptides for Treatment of Streptococcus mutans.

Dental plaque, formed by a Streptococcus mutans biofilm, is a major contributor to cavity formation. While antimicrobial strategies exist, the growing risk of antibiotic resistance necessitates alternative therapeutic solutions. Polyserotonin nanoparticles (PSeNPs), recently recognized for their photothermal property and promising biomedical applications, open up a new avenue for antimicrobial use. Here, we introduced a UV-initiated synthetic route for PSeNPs with improved yield. Using these PSeNPs, a cocktail treatment to reduce the viability of this cavity-causing bacteria was developed. This cocktail comprises an S. mutans-targeting antimicrobial peptide (GH12), an intraspecies competence-stimulating peptide that triggers altruistic cell death in S. mutans, and laser-activated heating of PSeNPs. The "peptide + PSeNP + laser" combination effectively inhibits S. mutans growth in both planktonic and biofilm states. Moreover, the cocktail approach remains effective in reducing the viability of S. mutans in a more virulent dual-species biofilm with Candida albicans. Overall, our results reinforce the utility of a multipronged therapeutic strategy to reduce cariogenic bacteria in the complex model oral biofilm.

Preventing proximal enamel caries in neighboring tooth with glass ionomer cement restoration and silver diamine fluoride pretreatment

ObjectiveTo investigate caries preventive effects of 38 % silver diamine fluoride (SDF) pretreatment on neighboring tooth proximal to glass ionomer cement (GIC), including conventional GIC (CGIC) and resin-modified GIC (RMGIC) restorations in an in vitro model. Methods: Human tooth blocks were restored withSDF+CGIC (Group 1), CGIC (Group 2), SDF+RMGIC (Group 3) or RMGIC (Group 4). Enamel specimen simulating proximal surface of neighboring tooth was placed in proximity to the restorations. The specimen underwent cariogenic challenge with cross-kingdom biofilm of Streptococcus mutans, Lacticaseibacillus casei and Candida albicans. After cariogenic challenge, the biofilm's growth kinetics, viability, and morphology were evaluated by propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), respectively. The enamel lesion depth, surface morphology and crystal characteristics were determined by micro-computed tomography (micro-CT), SEM and X-ray diffraction (XRD), respectively. ResultsPMA-qPCR demonstrated lower microbial growth in Group 1 and 3 compared with Group 2 and 4 (p < 0.05). CLSM showed the dead−to-live ratio in Groups 1–4 were 1.15±0.12, 0.53±0.13, 1.10±0.24 and 0.63±0.10, respectively (Group 1,3 > 2,4, p < 0.05). SEM revealed Groups 1 and 3 had scattered biofilm whereas Group 2 and 4 had confluent biofilm. Micro-CT showed the enamel lesion depths (µm) were 98±9, 126±7, 103±6 and 128±7 for Group 1 to 4, respectively (Group 1,3 < 2,4, p < 0.05). SEM revealed oriented and ordered enamel prismatic patterns in Group 1 and 3, not in Group 2 and 4. XRD showed the reflections of hydroxyapatite in Groups 1 and 3 were sharper than Groups 2 and 4. ConclusionSDF pretreatment enhances the preventive effect of GIC on proximal enamel surface on neighboring tooth through inhibiting cariogenic biofilm, reducing enamel demineralization and promoting enamel remineralization. Clinical significanceSDF pretreatment of GIC restorations can help prevent caries on neighboring teeth, particular for patients with high caries risk.

Postbiotic mediators derived from Lactobacillus species enhance riboflavin-mediated antimicrobial photodynamic therapy for eradication of Streptococcus mutans planktonic and biofilm growth

BackgroundStreptococcus mutans has been implicated as a primary causative agent of dental caries and one of its important virulence properties is an ability to form biofilm on tooth surfaces. Thus, strategies to prevent and control S. mutans biofilms are requested. The present study aimed to examine the eradication of S. mutans planktonic and biofilm cells using riboflavin (Rib)-mediated antimicrobial photodynamic therapy (aPDT) enhanced by postbiotic mediators derived from Lactobacillus species.Materials and methodsMinimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of Rib and postbiotic mediators were determined. The antimicrobial and anti-biofilm effects of Rib-mediated aPDT (Rib plus blue light), Rib-mediated aPDT in combination with postbiotic mediators derived from Lactobacillus casei (LC) (aPDT+ LC), and Rib-mediated aPDT in combination with postbiotic mediators derived from Lactobacillus plantarum (LP) (aPDT+ LP) were evaluated. The anti-virulence potential of Rib-mediated aPDT, aPDT+ LC, and aPDT+ LP were assessed by measuring the expression of the gtfB gene using quantitative real-time polymerase chain reaction (qRT-PCR) at the highest concentrations of Rib, LC, and LP, at which the S. mutans had proliferation as the same as in the control (non-treated) group.ResultsAccording to the results, the MIC doses of LC, LP, and Rib were 64 µg/mL, 128 µg/mL, and 128 µg/mL, respectively, while the MBC values of LC, LP, and Rib were 128 µg/mL, 256 µg/mL, and 256 µg/mL, respectively. Rib-mediated aPDT, aPDT+ LP, and aPDT+ LC showed a significant reduction in Log10 CFU/mL of S. mutans compared to the control group (4.2, 4.9, and 5.2 Log10 CFU/mL, respectively; all P < 0.05). The most destruction of S. mutans biofilms was observed after treatment with aPDT+ LC followed by aPDT+ LP and Rib-mediated aPDT (77.5%, 73.3%, and 67.6%, respectively; all P < 0.05). The concentrations of 31.2 µg/mL, 62.5 µg/mL, and 62.5 µg/mL were considered as the highest concentrations of LC, LP, and Rib, respectively, at which S. mutans replicates as same as the control group and were used for gtfB gene expression assay using qRT-PCR during Rib-mediated aPDT, aPDT+ LP, and aPDT+ LC treatments. Gene expression results revealed that aPDT+ LP and aPDT+ LC could decrease the gene expression level of gtfB by 6.3- and 5.7-fold, respectively (P < 0.05), while only 5.1-fold reduction was observed after Rib-mediated aPDT (P < 0.05).ConclusionOur findings indicate that aPDT+ LP and aPDT+ LC hold promise for use as a treatment to combat S. mutans planktonic and biofilms growth as well as anti-virulence as a preventive strategy to inhibit biofilms development via reduction of gtfB gene expression.

Fluoride release and antibiofilm of Alkasite restorative materials

This invitro study assessed fluoride ion release and antibiofilm activity of Alkasite materials against two types of bacterial spp. (Streptococcus mutans and Lactobacillus plantarum). Three different ion-releasing materials (Cention N, Cention Forte and Fuji IX GP) were used to make four groups. A total of 96 disc-shaped samples were prepared in polyethene mould, 32 samples (n=8) were used for evaluating fluoride ion release the samples were placed in vial containing 5ml of deionized water, and the measurements were recorded in four periods (1,7,21 and 28) days by utilizing an ion-selective electrode (ISE). 64 samples were used to evaluate the anti-biofilm activity of the materials groups against (S. mutans and L.plantarum), by using crystal violet assay for quantitative biofilm assessment (n=5 of each group for each bacterial spp.) and by SEM for the qualitative evaluation (n=3 of each group for each bacterial spp). Fuji IX GP registered the highest amount of fluoride release on 1st day of the observation period than Cention N and No primer was added to Cention Forte. On the 28th day, Primer added Cention Forte recorded the highest mean value of fluoride release among all of the groups. Primer-added Cention Forte has significantly more biofilm accumulation of both (Streptococcus mutans and Lactobacillus plantarum) than Cention N and No primer-added Cention Forte. Fuji IX showed significantly higher Streptococcus mutans biofilm accumulation compared to Cention N. Alkasite restorative materials showed a low potential for biofilm accumulation regarding both Streptococcus mutans and Lactobacillus plantarum.

Efficiency of the photodynamic therapy on viability of Streptococcus mutans in the oral cavity using chitosan nanoparticles: an in vitro study.

This study aimed to investigate the efficiency of antimicrobial photodynamic therapy (aPDT) on Streptococcus mutans biofilm in the oral cavity using the photosensitizer chloroaluminum phthalocyanine encapsulated in chitosan nanoparticles (ClAlPc/Ch) at three preirradiation times. Biofilms of Streptococcus mutans strains (ATCC 25,175) were cultivated on bovine tooth blocks and exposed to a 10% sucrose solution three times a day for 1min over three consecutive days. The samples were randomly distributed into five treatment groups (n = 5): (I) aPDT with ClAlPc/Ch with a preirradiation time of 5min (F5), (II) aPDT with ClAlPc/Ch with a preirradiation time of 15min (F15), (III) aPDT with ClAlPc/Ch with a preirradiation time of 30min (F30), (IV) 0.12% chlorhexidine digluconate (CHX), and (V) 0.9% saline solution (NaCl). After treatment, the S. mutans biofilms formed on each specimen were collected to determine the number of viable bacteria (colony-forming units (CFU)/mL). Data were analyzed for normality using the Shapiro-Wilk test and the analysis of variance (ANOVA) and Tukey HSD tests to analyze the number of viable bacteria (α = 0.05). The one-way ANOVA showed a difference between the groups (p = 0.0003), and the Tukey HSD posttest showed that CHX had the highest microbial reduction of S. mutans, not statistically different from the F5 and F15 groups, whereas the NaCl group had the lowest microbial reduction statistically similar to the F30 group. The results demonstrate that aPDT mediated by ClAlPc/Ch when used at preirradiation times of 5-15min can be an effective approach in controlling cariogenic biofilm of S. mutans, being an alternative to 0.12% CHX.

Antibacterial assessment of Ziziphus mauritiana Lam on inhibition of the growth and biofilm of Streptococcus mutans

Antibacterial assessment of Ziziphus mauritiana Lam on inhibition of the growth and biofilm of Streptococcus mutans