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.

Objective: To 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 methods: A 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). Result: When 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). Conclusion: S 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.

In-vitro and In-silico evaluation of antimicrobial and antibiofilm effect of Neem oil and Calcium hydroxide nanoparticles against Mutans Streptococci and Enterococcus faecalis isolated from endodontic infections.

Different Streptococcal species including Streptococcus mutans, Streptococcus sobrinus and Enterococcus faecalis are commonly isolated in root canal infections including refractory, recurrent, and persistent cases. Calcium hydroxide (Ca (OH)2) has been widely used in endodontics as an intracanal medicament. However, using new antimicrobial herbal alternatives offers promising potentials which can be additionally enhanced by using nanoparticles (NPs). In this study, we evaluate the antimicrobial efficacy and antibiofilm effect of Neem oil including its NPs preparations and we compare the effect of conventional Ca (OH)2 to Ca (OH)2 NPs using standard disc diffusion method and quantitative microtitre dish biofilm formation assay against common pathogens isolated from root canal samples. Molecular docking was used to test the binding of 10 Streptococcal macromolecules to 5 candidate neem active constituents. Neem NPs 0.125 mg/ml showed better antibacterial effect than both Neem 15 mg/ml and Neem 0.15 mg/ml. Ca (OH)2 NPs 0.125 mg/ml also showed better antibacterial effect than each of Ca (OH)2 10 mg/ml and Ca (OH)2 0.1 mg/ml. Best biofilm mass inhibition was achieved by Neem oil 0.15 mg/ml at 74.55% ( IQ: 67.36-87.65) and Neem NPs 0.0125 mg/ml at 59.33% (IQ: 51--75.27). For Ca (OH)2, the best biofilm mass inhibition was observed with Ca (OH)2 NPs 0.125 mg/ml at 54.7% (IQ: 42.37- 77.25). Both neem oil and neem NPs show promising antibacterial and antibiofilm potential against Mutans Streptococci group at low concentrations and hence are good candidates for use as endodontic medications. In silico analysis shows that both Sitosterol and Gedunin appear to be important active constituents of neem and possible drug candidates. Additionally, Ca (OH)2 NPs showed significantly higher antimicrobial effect against Mutans streptococci group than conventional Ca (OH)2 preparations.

Multifunctional Temporary Dental Nanofillers Enhanced with Synergistically Active Chlorine-Containing Molecules against Streptococcus mutans and Its Effects on Oral Epithelial Cells.

Temporary dental fillers are critical for safeguarding teeth during the period between caries removal and permanent restoration. However, conventional fillers often lack sufficient antimicrobial properties to prevent bacterial colonization. To address this issue, the study researches on the development of antimicrobial Temporary Dental Nano-Fillers (TDNF) capable of targeting multiple cariogenic pathogens, including Streptococcus mutans, Lactobacillus casei, Candida albicans, and mixed-species planktonic cells/biofilms, which play a significant role in the progression of dental caries. The TDNF was formulated using a combination of Chloramine-T (CRT) and Cetylpyridinium Chloride (CPC), both known for their antimicrobial efficacy, and embedded in a nanoparticle matrix of hydroxyapatite (HAP) and silicon dioxide (SiO2). The synergistic antimicrobial effect of CRT and CPC, with MIC90 values of 12.5 and 6.25 ppm, respectively, displayed potent activity against S. mutans. Proteomic analysis, including gene ontology and protein-protein interaction network evaluations, further confirmed significant disruptions in S. mutans metabolic and stress response pathways, highlighting the bactericidal effectiveness of the formulation against S. mutans. Additionally, the formulation demonstrated sustained antimicrobial efficacy against other cariogenic pathogens such as L. casei, C. albicans and mixed-species planktonic cells and biofilms over a 16-day period. The TDNF (HAP+SiO2+CRT+CPC matrix) exhibited superior mechanical properties with a compressive strength of 237.7 MPa, flexural strength of 124.3 MPa, and shear bond strength of 52 MPa. Biocompatibility tests conducted on human oral squamous carcinoma cells (OECM-1) indicated over 95% cell viability, affirming its safety for preclinical or clinical applications. The multifunctional TDNF developed in this study successfully combines mechanical reinforcement with broad-spectrum antimicrobial efficacy, offering a promising interim solution in dental restorations. Its ability to protect against microbial colonization, while maintaining structural stability, positions it as an effective temporary material that enhances patient outcomes during the period before permanent restoration.

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.

Early oral colonization of streptococcus mutans and lactobacilli species in infants: Investigating the relationship with maternal and environmental factors, from birth through the sixth month.

Objective: To assess the presence of Streptococcus Mutans (S.mutans) and Lactobacillus species (LB) of newborn-mother pairs using the real time polymerase chain reaction (qRT-PCR). Method: Subjects were selected from the patients followed in the Neonatology Clinic of Akdeniz University's Faculty of Medicine between the years 2017-2018. First samples collected within 48 hours after birth, and second samples were at six months. The samples were analyzed for the presence of S.mutans and LB using qRT-PCR. Mothers' smoking habits, education level, occupation, oral hygiene habits, DMFT scores and dietary history; Babies' delivery type, birth weight, feeding type, oral hygiene practices, feeding habits, bottle usage, pacifier usage, consumption of sugary foods, were also recorded. The effect of factors related to both mothers and infants was examined comparatively. Results: S.mutans DNA was detectable in 87% and LB DNA was detected in 37% mothers, while it was undetected in 63% mothers at the first sampling. S.mutans was detected in 37% and, while LB was detected in 5% of the newborns in the first 48 hours of their life. At the second sampling, the S.mutans and LB levels in infants have increased, while there has been no significant change in mothers. A significant relationship was found only between the increase in S.mutans in infants and the presence of erupted teeth. Conclusion: S.mutans and LB were able to colonize on the oral mucosal surfaces of edentulous newborns, with the counts of both bacteria increasing significantly with tooth eruption.

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.

Comparison of the Antimicrobial Efficacy of Conventional Versus Chitosan Re-inforced Heat-Polymerized Polymethylmethacrylate Dental Material: An In Vitro Study.

INTRODUCTION:  Polymethylmethacrylate (PMMA) is widely used in the fabrication of dentures due to its aesthetic appeal and mechanical strength. However, PMMA's susceptibility to microbial colonization often leads to oral infections such as denture stomatitis. Enhancing the antimicrobial properties of denture materials is crucial for improving patient outcomes. Chitosan, a natural biopolymer, possesses inherent antimicrobial properties and could potentially enhance the microbial resistance of PMMA. This study has investigated the potential of chitosan-reinforced heat-polymerized PMMA denture material to reduce microbial colonization. AIM:  The aim of the study was to evaluate and assess the anti-bacterial and antifungal properties of chitosan-reinforced heat-polymerized PMMA with conventional heat-polymerized PMMA Materials and methods: Chitosan-reinforced PMMA samples were fabricated with varying chitosan concentrations (0% control, 5%, 10%, and 15% by weight). The fabrication involved mixing chitosan powder with PMMA powder, adding monomer liquid, followed by mixing, packing, and curing using the conventional heat polymerization technique. The antimicrobial efficacy was assessed in vitro using two common oral pathogens: Streptococcus mutans and Candida albicans. Blood agar plates were used for S. mutans and Sabouraud agar plates were used for C. albicans. Each sample was placed on the respective agar plates inoculated with a standardized microbial suspension and incubated at 37°C for 24 hours. The number of colony-forming units (CFUs) was counted to quantify microbial growth. Statistical analyses, including linear regression analysis, one-way ANOVA test, and Pearson correlation were performed to evaluate the relationship between chitosan concentration and antimicrobial efficacy. The p-value was calculated to determine the statistical significance of the results. RESULTS:  The chitosan-reinforced PMMA samples showed significantly greater antimicrobial efficacy compared to the conventional PMMA samples. The CFU counts for both S. mutans and C. albicans decreased with increasing chitosan concentration. Linear regression analysis indicated a strong negative correlation between chitosan concentration and CFU counts, with Pearson correlation coefficients of -0.97 for S. mutans and -0.98 for C. albicans. ANOVA analysis revealed a statistically significant difference in antimicrobial efficacy across different chitosan concentrations (p < 0.001). CONCLUSION:  Incorporating chitosan into heat-polymerized PMMA significantly enhances its antimicrobial properties against S. mutans and C. albicans. The antimicrobial efficacy improves with higher concentrations of chitosan, with the 15% chitosan-reinforced samples showing the most substantial reduction in microbial growth. These results suggest that chitosan-reinforced PMMA dentures could be a superior alternative to conventional PMMA dentures, potentially reducing denture-related infections and improving oral health outcomes for denture wearers.

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.

Immunoinformatics Design of a Multiepitope Vaccine (MEV) Targeting Streptococcus mutans: A Novel Computational Approach.

Dental caries, a persistent oral health challenge primarily linked to Streptococcus mutans, extends its implications beyond dental decay, affecting over 4 billion individuals globally. Despite its historical association with childhood, dental caries often persists into adulthood with prevalence rates ranging from 60 to 90% in children and 26 to 85% in adults. Currently, there is a dearth of multiepitope vaccines (MEVs) specifically designed to combat S. mutans. To address this gap, we employed an immunoinformatics approach for MEV design, identifying five promising vaccine candidates (PBP2X, PBP2b, MurG, ATP-F, and AGPAT) based on antigenicity and conservation using several tools including CELLO v.2.5, Vaxign, v2.0, ANTIGENpro, and AllerTop v2.0 tools. Subsequent identification of linear B-cell and T-cell epitopes by SVMTrip and NetCTL/NetMHC II tools, respectively, guided the construction of a MEV comprising 10 Cytotoxic T Lymphocyte (CTL) epitopes, 5 Helper T Lymphocyte (HTL) epitopes, and 5 linear B-cell epitopes, interconnected by suitable linkers. The resultant MEV demonstrated high antigenicity, solubility, and structural stability. In silico immune simulations showcased the MEV's potential to elicit robust humoral and cell-mediated immune responses. Molecular docking studies revealed strong interactions between the MEV construct and Toll-Like Receptors (TLRs) and Major Histocompatibility Complex (MHC) molecules. Remarkably, the MEV-TLR-4 complexes exhibited a low energy score, high binding affinity, and a low dissociation constant. The Molecular Dynamic (MD) simulation analysis suggested that MEV-TLR-4 complexes had the highest stability and minimal conformational changes indicating equilibrium within 40 nanosecond time frames. Comprehensive computational analyses strongly support the potential of the proposed MEV to combat dental caries and associated infections. The study's computational assays yielded promising results, but further validation through in vitro and in vivo experiments is needed to assess its efficacy and safety.

Surface characteristics and bacterial adhesion on single-shade composite resins: A comparative in vitro study of one-step versus multi-step polishing techniques.

This study evaluated the effects of two polishing systems, OptraGloss (G; one-step) and OptiDisc (D; multi-step), on surface roughness (SR), contact angle (CA), surface free energy (SFE), and bacterial adhesion on three single-shade composite resins: Omnichroma (O), ZenChroma (Z), and Charisma Diamond One (C). Data for SR, CA, SFE, and adhesion of Streptococcus mutans (S. mutans) and Streptococcus mitis (S. mitis) were analyzed using one-way ANOVA, Tukey post-hoc tests, and Pearson correlation (α=0.05). Multi-step polishing groups (OD, ZD, and CD) exhibited significantly lower SR (0.18, 0.18, and 0.29 µm, respectively) compared to OG (0.46 µm), ZG (0.30 µm), and CG (0.44 µm) (p<0.05). The highest CA was observed in ZG (91.6º). S. mitis adhesion was greater than S. mutans in all groups except OG. A significant correlation was observed between SR and the adhesion of S. mutans (r=0.693, p<0.001). Polishing systems applied to single-shade composite resins did not impact the SFE but affected SR, and bacterial adhesion.

Effect of medicated toothpastes and Tooth Mousse on cariogenic microbes of the oral cavity: An in vitro study.

Background: Dental caries, commonly known as tooth decay is a widespread oral health problem mainly attributed to the activity of cariogenic bacteria, such as Streptococcus mutans and Lactobacillus species. Tooth Mousse, containing remineralizing agents, herbal and fluoride containing toothpaste with antimicrobial agents have been developed to target cariogenic bacteria. Herbal, fluoride toothpaste, and Tooth Mousse are commonly prescribed to prevent, reduce, and control dental caries. Aim: This study aims to analyze the effect of Tooth Mousse and medicated toothpastes on S. mutans and Lactobacillus acidophilus using direct contact test. Methodology: L. acidophilus and S. mutans were cultured on Mueller-Hinton agar (MHA-Hi media) using sterile cotton swabs and plates were dried for 15 min. Toothpastes (Dabur Red, Pepsodent) and Tooth Mousse were used at 1:1 dilution using sterile pyrogen-free distilled water. Fifty microliter of toothpastes and Tooth Mousse were introduced into each well. The plates were incubated at 37°C for 24 h. Results and Discussion: The antimicrobial activity was evaluated by measuring the diameter of zones of inhibition (mm). The toothpaste containing fluoride (A) showed greater zone of inhibition compared to herbal toothpaste (B) whereas Tooth Mousse (C) did not show any zone of inhibition. Conclusion: Among herbal and fluoride toothpaste, fluoride containing toothpaste showed more zone of inhibition thereby attributing to its increased antimicrobial property on S. mutans and L. acidophilus.

An Assay on the Antibactericidal Functionality of Synthesized Mg-Doped ZnO Nanoparticles on the Dental Microbes.

We succeeded in producing pure and magnesium-doped zinc oxide nanoparticles (Mg-Zn NPs) by making use of a Prosopis farcta leaf extract and subsequently distinguished the quality of our NPs with the use of field energy scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), powder X-ray diffraction (PXRD), and UV-vis. In correlation to our observations, the particulates were spherically produced at a size of 20 nm with the ability to cause antimicrobial impacts on Streptococcus mutans bacteria and Candida albicans fungi. Inhibition zones of 18 ± 0.3 and 24 ± 0.3 mm were obtained for 5% Mg-Zn NPs against bacteria and fungi, respectively. Based on these results, our work suggests a practicable proposition for our synthesized product to be considered as a worthy alternative for dental and oral utilizations.

The impact of a-tomatine on shear bonding strength in different dentin types and on cariogenic microorganisms: an in vitro and in silico study.

INTRODUCTION: The objective of this study is to investigate the shear bonding strength of a glycoalkaloid, also a novel matrix metalloproteinase enzyme known as α-tomatine, on two different surfaces of dentin (sound & caries-affected) and its efficacy against cariogenic microorganisms using in vitro and in silico methods. METHODS: The effect of a-tomatine at different concentrations (0.75 / 1 / 1.5 µM) on shear bonding strength in caries-affected and sound dentin was also investigated (n = 10; each per subgroup). The analysis of shear bonding and failure tests was conducted after a 24-hour storage period. Fracture surfaces were examined under a scanning electron microscope. A stock solution 3 mM of a-tomatine was prepared for antimicrobial evaluation. Antimicrobial activities of the agents against Streptococcus mutans ATCC 25175, Lactobacillus casei ATCC 4646, and Candida albicans ATCC 10231 standard strains were investigated by microdilution method. In addition, through the method of molecular docking and dynamic analysis, the affinity of a-tomatine for certain enzymes of these microorganisms was examined. RESULTS: The pretreatment agent and dentin type significantly influenced shear bonding strength values (p < 0.05). As the molarity of a-tomatine increased, the bonding value decreased in sound dentin, while the opposite was true in caries-affected dentin. According to molecular docking and dynamic analysis, the highest affinity was observed in L. casei's signaling protein. Microdilution assays revealed a-tomatine to exhibit fungicidal activity against C. albicans and bacteriostatic effects against S. mutans. No antimicrobial effect was observed on L. casei. CONCLUSION: a-tomatine demonstrates a positive impact by serving as both a pretreatment agent for bonding strength and an inhibitor against certain cariogenic microorganisms.

YkuR functions as a protein deacetylase in Streptococcus mutans.

Protein acetylation is a common and reversible posttranslational modification tightly governed by protein acetyltransferases and deacetylases crucial for various biological processes in both eukaryotes and prokaryotes. Although recent studies have characterized many acetyltransferases in diverse bacterial species, only a few protein deacetylases have been identified in prokaryotes, perhaps in part due to their limited sequence homology. In this study, we identified YkuR, encoded by smu_318, as a unique protein deacetylase in Streptococcus mutans. Through protein acetylome analysis, we demonstrated that the deletion of ykuR significantly upregulated protein acetylation levels, affecting key enzymes in translation processes and metabolic pathways, including starch and sucrose metabolism, glycolysis/gluconeogenesis, and biofilm formation. In particular, YkuR modulated extracellular polysaccharide synthesis and biofilm formation through the direct deacetylation of glucosyltransferases (Gtfs) in the presence of NAD+. Intriguingly, YkuR can be acetylated in a nonenzymatic manner, which then negatively regulated its deacetylase activity, suggesting the presence of a self-regulatory mechanism. Moreover, in vivo studies further demonstrated that the deletion of ykuR attenuated the cariogenicity of S. mutans in the rat caries model, substantiating its involvement in the pathogenesis of dental caries. Therefore, our study revealed a unique regulatory mechanism mediated by YkuR through protein deacetylation that regulates the physiology and pathogenicity of S. mutans.

Monomelittoside and Dichotomoside D from bark extract of Alstonia scholaris (L.) R. Br. inhibits dental caries pathogen Streptococcus mutans.

Dental caries advances to be a significant global health concern, primarily attributed to the virulent actions of Streptococcus mutans. The antibacterial property of the bark extract of Alstonia scholaris was assessed using standard disc diffusion assays, which revealed significant inhibition of S. mutans. Subsequently, we determined the Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) revealed potent antibacterial activity of bark extract against S. mutans, at MIC and MBC values 62.5 and 125 µg/mL, respectively and antibiofilm activity at 125 µg/mL. Furthermore, cytotoxicity assays showed no adverse effects on mammalian cells. Moreover, we employed liquid chromatography-mass spectrometry to identify bioactive compounds in the bark extract and revealed the presence of major active compounds as Monomelittoside and Dichotomoside D effective in targeting the S. mutans. These findings showed that, the promising antibacterial efficacy of Monomelittoside and Dichotomoside D, highlighting their potential as natural therapeutics for combating dental caries.

Optimizing Desmostachya bipinnata-derived platinum nanoparticles for enhanced antibacterial and biofilm reduction.

This study presents the green synthesis and comprehensive characterization of platinum nanoparticles (PtNPs) using Desmostachya bipinnata (Db) extract, incorporated into two innovative mouthwash formulations (MW1 and MW2). UV-Vis spectroscopy confirmed the successful synthesis of PtNPs, with distinct absorption peaks between 250 and 600 nm. Fourier-transform infrared (FTIR) spectroscopy identified hydroxyl and carbonyl functional groups, critical for the bioreduction and stabilization of PtNPs. High-resolution transmission electron microscopy (HR-TEM) revealed uniformly dispersed, spherical nanoparticles with a size range of 10-20 nm, while dynamic light scattering (DLS) confirmed a hydrodynamic diameter of 10-30 nm and a low polydispersity index (PDI) of 0.238, indicating excellent stability. Both formulations exhibited robust antimicrobial, antibiofilm, and anti-plaque properties, with MW2 showing superior efficacy, particularly against Staphylococcus aureus and Escherichia coli, as well as a notable 70 % reduction in biofilm formation and a 60 % plaque reduction within 2 h of treatment. The study underscores the potential of Desmostachya bipinnata-derived PtNPs as a promising alternative to conventional mouthwash, offering enhanced antimicrobial efficacy, biofilm disruption, and plaque prevention, alongside excellent stability and biocompatibility for oral healthcare applications.

Influence of Polymerization Protocol on Adhesion and Proliferation of Streptococcus mutans on Three Dental Composite Resins.

Background/Objectives: The aim of this in vitro study was to analyze and compare the Streptococcus mutans ability to adhere and form biofilm on the surface of light-cured VS heat-cured dental composite resins; Methods: Three composite resins with different chemical formulations were selected: GrandioSO (GR), Venus Diamond (VD) and Enamel Plus Hri Biofunction (BF). Disk-shaped specimens were manufactured by light-curing the composite resins (light-cured subgroups) and subjecting them to a further heat-curing cycle at 80° for 10 min (heat-cured subgroups). Specimens were analyzed for planktonic CFU count (CFU/mL), sessile CFU count (CFU/mL) and for biomass quantification (OD570nm); Results: The planktonic CFU count was higher in all the light-cured subgroups than in the heat-cured subgroups (light-cured: GR = 7.23 × 106, VD = 2.14 × 107, BF = 4.40 × 107; heat-cured: GR = 4.89 × 106, VD = 4.95 × 106, BF = 2.80 × 107), with a statistically significant increase for BF and VD. Focusing on the sessile CFUs, both GR (light-cured = 7.49 × 106; heat-cured = 3.97 × 106) and VD (light-cured = 2.93 × 107; heat-cured = 6.07 × 106) showed a significantly increased number of colonies in the light-cured subgroups. The OD570nm values recorded for the light-cured BF subgroup (0.4280) were significantly increased compared to the heat-cured BF subgroup (0.1931); Conclusions: A more complete polymerization protocol seems to lead to a potential reduction in the risk of secondary caries.

Deciphering the killing mechanisms of potassium iodide in combination with antimicrobial photodynamic therapy against cross-kingdom biofilm.

Introduction: The co-existence of S. mutans and C. albicans is frequently detected in root caries and early child caries and is reported to be associated with recurrent caries. The aim of this study was to investigate the effects of potassium iodide (KI) in combination with toluidine blue O-mediated antimicrobial photodynamic therapy (aPDT) on S. mutans and C. albicans mixed-species biofilm, as well as the antibiofilm mechanisms involved. Methods: Mixed-species biofilm was constructed of S. mutans and C. albicans on dentin blocks. The antibiofilm efficacy, cytotoxicity and antibiofilm mechanism of KI in combination with aPDT were determined and evaluated. Results: KI+TBO-aPDT treatment caused reduction in microorganism counts, metabolic activity, and biofilm biomass of mixed-species biofilm without inducing cytotoxicity to hDPCs (human dental pulp cells). Observations such increased ROS (reactive oxygen species) levels, impaired cell membrane function, cell apoptosis and reduced expression in several genes seem to be artifacts of reduced growth and general killing by KI+TBO-aPDT treatment. Discussion: These data suggested that KI in combination with aPDT as an innovative approach to combat S. mutans and C. albicans biofilm, and thus as an optional treatment for caries.

High release of Candida albicans eDNA as protection for the scaffolding of polymicrobial biofilm formed with Staphylococcus aureus and Streptococcus mutans against the enzymatic activity of DNase I.

This study aimed to determine the protective role of the high release of C. albicans extracellular DNA (eDNA) in a polymicrobial biofilm formed by S. aureus and S. mutans in the course of DNase I treatment. A tube-flow biofilm bioreactor was developed to mimic biofilm formation in the oral cavity. eDNA release was quantified by real-time PCR (qPCR) and confocal microscopy analysis were used to determine the concentration and distribution of eDNA and intracellular DNA (iDNA). The mean amount of eDNA released by each species in the polymicrobial was higher than that in monospecies biofilms (S. aureus: 3.1 × 10-2 ng/µl polymicrobial versus 5.1 × 10-4 ng/µl monospecies; S. mutans: 3 × 10-1 ng/µl polymicrobial versus 2.97 × 10-2 ng/µl monospecies; C. albicans: 8.35 ng/µl polymicrobial versus 4.85 ng/µl monospecies). The large amounts of eDNA released by C. albicans (96%) in polymicrobial biofilms protects the S. aureus and S. mutans cells against the degradation by DNase I and dampens the effect of clindamycin.

Comparative evaluation of surface roughness and bacterial adhesion on two bioactive cements: an in-vitro study.

BACKGROUND: Dental restorative materials are recognized as artificial niches that facilitate the adherence and accumulation of oral microorganisms. To mitigate oral diseases and extend the lifespan of restorations, it is advantageous to use dental materials that exhibit low susceptibility to bacterial adhesion. OBJECTIVE: To evaluate and compare bacterial adhesion on two bioactive restorative materials, a glass hybrid restorative, and an alkasite with a nanohybrid resin composite as a positive control. The secondary objectives were to compare the surface roughness (SR) of the materials and determine the correlation between the bacterial adhesion and the SR. MATERIALS AND METHODS: The samples consisted of 33 polished discs of each material: Group A: Tetric® N-Ceram (nanohybrid resin composite), Group B: Equia Forte™ HT Fil (glass hybrid restorative) and Group C: Cention N® (alkasite). Streptococcus mutans cultures were inoculated and after 24-hours of incubation, bacterial adhesion was measured by measuring optical density (OD) and number of colony forming units (CFUs). After 96-hours incubation, the bacterial cell count was determined using scanning electron microscopy (SEM). SR was assessed using surface profilometer. RESULTS: Alkasite had significantly lower OD and CFUs (p < 0.001 and p = 0.015 respectively). According to the SEM analysis, the glass hybrid restorative had lower mean bacterial cell count with no significant difference between the groups. The nanohybrid composite had the smoothest surface that was significantly lower than the alkasite and glass hybrid restorative (p = 0.002). None of the groups demonstrated a correlation between bacterial adhesion and SR. CONCLUSION: Alkasite impedes bacterial adhesion better than the glass hybrid restorative and nanohybrid composite, while smoother surfaces are achieved with the nanohybrid composite.